Building a BETTER attic - Unvented + Conditioned attics 101

[@BrightAngel007]

We so need some videos on taking an attic like you had at the beginning and having it converted to a conditioned attic.

[@LukasEragon]

yeah this would be helpful to me also (doing a renovation not a new build)

[@CertifiedMailSignatureRequired]

try this old house - they've been rocking it before youtube

[@handleuponit]

Good idea. I’ll post one on a conditioned attic.

[@OmarReyes-pm3fr]

Im a HVAC TECH in south Texas and those conditioned attic spaces are lovely

[@AD-1138]

Maybe you can answer this! I cant find the video....yet....of the installation of that conditioned attic....whats with all those smaller white ducts?

[@SBC97281]

@@AD-1138 The small white ducting is for fresh air, it is in the video, but the go over it pretty quick.

[@handleuponit]

@@AD-1138 small white vents are bathroom vent fans.

[@literalsweatequity]

Amen to the importance of a sealed attic, Matt. When I insulated mine, nobody wanted to believe me that it was going to be 75 degrees in side with 100 outside. Got the proof today! 101 outside, 71 inside. During the manual J calculations I had to argue with the engineer that I wasn't going to have 40% energy loss in the attic because all my ducts were in the conditioned space. And because the attic is my return air "duct" that saves even more energy. My A/C guy and I decided to downgrade from a 5 ton unit to a 3 ton after he saw the results. Thanks for the great videos. Amazing what one can learn!

[@andrewmckinlay2964]

What do you mean your attic is your return duct? You have vents between the attic and house?

[@literalsweatequity]

@@andrewmckinlay2964 The problem with sealed attics is that you get stagnant (and humid) air in them while your return air is passing through it through return air ducts. A truely "conditioned attic would require supply and return ducts to cool/heat the attic. We opted to passively condition the attic by running all return ducts with terminations in different attic locations. Since the attic is sealed it operates like a giant return plenum, concentrating and mixing the return air from the house. The air handler then pulls the air from the attic and recirculates it throughout the house where needed. In addition, this gives us the opportunity to manage the humidity with a whole house dehumidifier and let the dry air in the attic mix with the return air from the house. We have several thermometers with hygrometers throughout the house to verify that this principle works consistently. Hope this answers your question. - Wolf.

[@fwaynedavis]

Having lived in a Texas home with a conditioned attic I can confirm it is an order of magnitude better than conventional. It was proven as my neighbors had conventional with Identical builder. I opted to spring for the initial $$ up front. Result? My heating/cooling costs were 1/3 my neighbors with same size homes (2500 sq. ft). No Dust, no bugs, super quiet, and no dread when handling things in attic. I can verify also the cost upfront was easily offset by energy savings, and no doubt made my home sell at a higher price than comparables due to my ability to prove energy costs based upon actual bills. I will never live without a conditioned attic ever again.

[@williameldridge9382]

Last I checked, doing a conditioned attic increases the cost of your build by like 20-30k. Spray-foaming alone will run you like 10k on a house that size, then add in all the extra building materials to make an attic like that. It costs about $133 on average to cool per month at 2500 square feet (the median house size in the us actually). It's great if your bills are a third of your neighbors, but to make up for that much money you'd have to own that house for DECADES and that is just to break even. To actually start seeing a benefit you'd essentially have your house paid off (with an average 30 year loan). The person that didn't spend that extra 20k-30k will have their house paid off that much sooner as well. You have to think long term here. Yes, that house is more efficient overall, and is in fact an energy saver. But it's gonna need multiple owners and decades to really pull ahead of a traditional attic, and those building the home will have to be able to afford said house. Meaning they either need to put off building longer so they can save up more money and potentially get a better career to afford the higher payments, or they'll be struggling to pay for the house and likely never pay it off before they die/retire. It's all about costs, really. And with the housing market right now, and the cost of building materials, you can double or even triple those extra costs. So suddenly that 20-30k is an added 40-60k, or even a 60k-90k extra cost (depending on many factors including house size). It's all about costs vs benefit and for a lot of people it won't be worth it.

[@fwaynedavis]

@@williameldridge9382 I agree, costs today aren't a direct cost savings. But there a huge thing to ponder. It is the running and lifetime costs. The cost in in today's dollars. 20 years from now the initial amount will be beans, and energy costs will be massive in comparison. Actually it can become a reality much sooner with current political pressures. It adds more than energy efficiany it creates strength, seals moister prone areas (we live i black mold country) and creates a storage area where you valuable dont get ruined by 150+ degree summer heat BTW.. where are you getting those costs for materials and labor? You must live in a non-right to work state where unions rule. Here in TX My neighbor just foamed his place at $2 Sq/ft. Its about 2.5X conventional fiberglass, But nowhere near those numbers you are getting.

[@marcrcbally]

Remodeled a 3 apartment house using only rock wool as insulation for both temperature and sound. Worked wonders, afterwards you could not hear a sound between the apartments while before you could understand any conversation that was above a whisper. Not only is rock wool wonderful to work with, it's not itchy in the least. And as a bonus, it also acts as a fire barrier.

[@VanHalen2TheTop]

We call it the green itch when we use it framing lol

[@johnlee7085]

I loved working with the rockwool on some of our remodeling. Just couldn’t find it consistently. Definitely chose it when I could.

[@bigredwag]

Consider maybe a vid on how to convert a vented attic into an unvented conditioned attic?? If that even makes sense 😆

[@seannewton93]

Yes please my house was built in the twenties and I would love to see what it takes to do the conversion

[@RobyWanKenobi]

That would be great!

[@danielbuckner2167]

You will have to wait until a vendor will sponsor that video.

[@patrickknapp5867]

Yes I agree. I know how but there still are tricks and questions I have

[@cinaibur]

Absolutely this! I installed a new 30 year roof with a ridge vent several years ago, and now I'd love to seal it without needing exterior roof work. Can I seal the soffits and the ridge vent from the interior before insulating?

[@hvfd5956]

I really like what I saw in this video. Very neat technology. I also like that you thought about the fresh air needs. I would not have thought of that need, but should have since I grew up in the days of the gas space heaters. As a former volunteer fire fighter, no or at least less smoke is a big deal. Current trends are to cut a bunch of holes in the roof to let the smoke and heat out so you can see where the fire is. In a house fire with someone trapped, the firefighters had to back out when the FLIR camera showed the temperature at 742 degrees, roughly 4 feet off of the floor. The trapped person didn't make it. As the fire captain said, "no one survives that kind of heat". The open core bedroom doors just went whoosh and only the frame was left. This was a 50 year old brick 3-sides house with typical shingle roofing. That was the problem. With the room temperature that high, the tar on the bottom of the shingles melted and dripped through the sheeting, then burst into flame in the attic - making the temperature that much higher. Once they got the attic temperature down a little, they were able to go in and pull ceiling to finish the lowering of the temperature. The whole thing was out in about 5 minutes after that. As a result of the SMOKE, the city inspector required that the left overs be taken to a special hazardous materials dump. The smoke alone caused everything to be classified as hazardous. If your house catches on fire, please remember what we taught you in elementary school, get flat on your belly and pretend you are an alligator then crawl out. Don't stand up! Your lungs can't handle the heat or the smoke.

[@handleuponit]

Wow. Incredible story

[@юриймаслихов]

This is a valuable addition to my woodwork collection kzbin.infoUgkxbnOKZBE4evMO5V2vroHeCjq6d_MV6wJO I still will rate this woodwork plan as the best in my reference library. It always seem to stand out from the rest whenever you go through the library. This is a masterpiece.

[@staugustinebackwater]

Here’s the issue with unvented attics. The home will self destruct in the absence of electricity (unvented attics REQUIRE air conditioning underneath constantly). Many homes in Florida that either went without power due to hurricane or foreclosure filled up with black mold. Most had to be stripped to the framing to repair. A vented attic is self-drying without power so for our off-grid ready home an unvented attic would have been a horrible choice. I like your videos but when you omit all the cons while touting the pros it seems like a sales pitch.

[@MrSloika]

Yup, in a high humidity, high temp area, this requires continuous AC. Even a short interruption of AC will end in disaster.

[@bigd7355]

I'd rather deal with that by having a backup generator than deal with the nasty vented attic which will definitely have mold anyway. Vented attics are disgusting.

[@staugustinebackwater]

I have been in construction for over 30 years and have never seen a vented attic full of mold in Florida, which by the way is probably the most humid state in the nation. A vented attic is designed to be self drying, and has worked for centuries. Unvented attic’s are new, and require all of your modern conveniences to be functioning perfectly in order to keep your home from self-destructing. Unvented attic’s have their benefits, but people need to be aware that they also require maintenance. We have a back up generator. But even with our 1000 gallon tank, it is not an unlimited supply. Just during the last hurricane we were without power for over two weeks. We have solar as well and are prepared to go for extended period of time, but air conditioners are too power-hungry to use if you were going to be off of the grid for more than a couple of weeks.

[@MrSloika]

@@staugustinebackwater Yup. I live in New Jersey, which has summers that are as humid as Florida. I live in a one hundred year old house. No mold in the attic.

[@kevinlopezobrien5366]

@@bigd7355 seems like your attic venting is insufficient then. Might be blocked up with insulation. Does your attic have insulation vent baffles installed?

[@atlantasailor1]

My attic used to go to 130F in summer. I had spay foam installed and it rarely reaches 90F. The electric bill has been reduced by about one third. But the more important thing is that the AC cools the house much easier. From Atlanta… the other benefit is that the attic is much more usable because you don’t temperature extremes. My attic is floored so it’s like adding extra rooms to the house.

[@leroyconley5647]

having been raised in Florida all my life I would have to say this is the best idea I ever saw on building an attic the right way

[@user-xl9pm4tx4p]

i had 2 new homes 1 in Pa 1 sw FL dumb thing in FL is the ductwork in attic and water pipes in attic summer takes gallons of water which is expensive her to not burn your hand it wash them and the efficiency loss on a/c saves builders a fortune but cost extra every month

[@duelette]

Old time builder here. With the USB roof boards if there is any leaks your roof is shot and it's hard to tell with foam sprayed on your Attic ceiling. Another thing is the cost in residence your homes 1800 to 2,000 square feet the cost increases so much that people cannot afford to buy the home. In most cases houses that small do not have much storage in the Attic anyway. Pros and cons to everything.

[@danielhoughtelling9721]

The biggest practice change is trusses vs rafters. Newer houses use trusses because they are faster to install. Most people who can afford on site cut rafters do so for the extra attic storage space.

[@reaperthemad8731]

Also, if you're in an area where high winds can be an issue (tornadoes/hurricanes) check what happens to the prefab truss roofs.

[@mitchjohnson4714]

Maybe they can do it with attic trusses.

[@johnlee7085]

There are a variety of truss designs. Some easily allow for use of the attic space.

[@mistyjackson8766]

We have an unvented attic and it has its ups and downs. live in california and out attic never gets above 85 degrees even if its 110 outside. Now this is great during the winter cause it really insulates our house and inside will never drop below 65. However during the summer after the long hot day and when it really cools down outside it takes forever for the inside of our house to cool down even if we have a lot of windows open. Its like a greenhouse effect and the house doesnt cool down until the attic finally cools down.

[@johnlee7085]

We love our whole house fan on those hot days when it gets below 80 by 9 pm. We’re good without ac til late mornings. Maybe that’s where Matt is talking about the fresh air resupply?

[@brayanmartinez5434]

Keeping it 100% real, I’ve been doing contracting for years now and I can’t even imagine customers wanting to spend all that money. 4” of close cell your looking around $5-$6 per sqft depending on the area and each bucket of costing is $300 each. In Texas you do not need 4” of close cell at all. In Canada we’re temperature goes under 0 use 3”. It’s amazing what their doing but way out of the budget of average Americans.

[@robbiewahl9860]

We do need the 4” (and more) in the south and southeast except for opposite reasons as you. We want to control heat and keep the a/c where it belongs. Building code in my part of Alabama requires R-30 or better. Biggest problem with this conversion idea is roofing material and warranty. Most materials except membranes and some metal roofs require backside ventilation (especially shingles) to prevent excessive ware on the asphalt plys and melting of the roof products and coatings. It’s also a problem with water vapor (depending on the roof type). We’ve done exactly this type of thing but have to use a ventilated nail base or put metal on furring strips.

[@27photogger]

Robbie Wahl roofing membranes as in the peel and stick membranes?

[@hailexiao2770]

3 inches of the best spray foam is maybe R-22.5, which is terrible for a roof in Texas, much less Canada.

[@hailexiao2770]

@@drlava641 Put a layer of cedar breather between the deck and the asphalt shingles, in effect venting above the deck instead of below it.

[@robbiewahl9860]

@@27photogger no, I refer to commercial membranes such as TPO, EPDM or PVC. The only peal-and-stick that, I think, is appropriate would be a Modified Bitumen type and you’d have to check with the manufacturer.

[@k55f5r]

I used radiant foil OSB when I built my house in SoCal, the attic was 20° cooler than the outside in 100°+ days. Well worth the additional cost.

[@MrWiseinheart]

Can only imagine the price of that today considering the price of normal OSB..

[@V3VoVo]

@@MrWiseinheart thanks to the liberal policies

[@butch8792]

@@V3VoVo exactly every cost increase in the world is directly related to liberal policies

[@Jonasty00]

@@butch8792 yes! I’m glad we’re on the same page

[@Moondoggy1941]

@@butch8792 No, just 75% of them.

[@rustedoutwrench]

Up in the nothern states at least near me its called a hot attic because it's heated in the winter

[@falfield]

In England, a 'conditioned roof' is referred to as a 'warm roof'. In colder climates (colder than Texas is most of the time - but maybe not MUCH colder) it's vital to have a vapour control layer (VCL - usually a membrane) on the warm (inside) side of the insulation so that moisture-laden warm air cannot move from the living space towards the colder outside, which would result in interstitial condensation. This is ruinously damaging for out of sight woodwork. What we learnt as householders doing a retrofit conditioned roof was that most roofers knew less about this new constructional method than we (who had taken an interest) did. They, being used to loft spaces being ventilated, just did not 'get' the importance of the VCL....which is very tricky to implement properly at abutments and penetrations. A warm roof, as Matt says, is brilliant - but it has to be done right.

[@DirkTeucher]

Here in the UK with our wet climate that spray foam 4:56 is deadly to wood beams in the roof. Do not use spray foam like this in a wet climate. We bought a house which had it done 5 years prior and I could crumble the wood under the foam with my bare hands. We were lucky the roof did not cave in on us and we had to replace most of the roof in the end. What happens in a wet climate is the water soaks into the wood throughout the year but especially during the winter but does not get time even during our "3 month summer" to dry out fully. This is because the spray foam first of all allows the water to pool and collect in between the spray foam and the wood but also prevents the heat from the house from getting to the wood at all which helps dry the wood. In a wet climate stick to rock wool or glass wool insulation if you want your wood to last. I think I would even be hesitant to use spray foam insulation in Texas without creating space for the wood to breath. Let me know if 5 years how it held up.

[@chadleach6009]

Huh, that's odd because it's been used extensively here in Florida for years now with absolutely stellar performance. Sounds to me like there were underlying issues with that property.

[@DirkTeucher]

@@chadleach6009 Our roof was 100+ years old so the damp proof sheet between the wood and the tiles was not exactly performing well. This meant moisture could get into the wood and collect over years between the foam and the wood as i said. The wood beams which were not fully covered in foam were able to breath just fine and dryed out in the summers nicely. The others covered in foam were wet and crumbled in my hands. Wood does rot in water especially old wood and our houses here in the uk are 100 - 200 years old easy so i think that + the temperature + how it is installed + roof type/angle are all factors. I imagine this stuff works great in many scenarios but I will be sticking with glass wool insulation which breathes nicely. Also removing that foam is a major pain too. Took all day to scrape it off the wood when we replaced 90% of the roof. Lots of landfill. Glass wool could have been put back in place after repairs so i think of foam as "fast food roofing" now. Not for me. I will also assume the owners are trying to hide problems with the roof in any future properties i purchase which luckily we also did when we viewed this property 5 years ago. We asked for 8000 off as we thought the roof might need repairs which it did.

[@AnN-py2em]

The thing I appreciate most about this video is how serious this man takes his foam, his job, and the willingness to spread his knowledge. It feels like it’s getting harder to find people that take so much pride in their livelihood.

[@billclinton6040]

Building a conditioned attic is essentially adding more square footage to your house. I can tell you right now, if I was going to spend the money to finish my attic like his, it better be livable like a second or third story, not just a comfy space for duct work.

[@trex2092]

Enjoy your high cooling bills while you are at it.

[@trex2092]

Some people just don't get it. What is fun about having your ductwork bake in an oven?

[@NoBody-ro3xj]

Comfy space for your storage, and for the future workers that have to do repairs instead of sweating head to toe.

[@fraidykat]

Do you enjoy paying higher taxes too? Because a finished attic space that is not part of the square footage is storage space that isn't counting against your property taxes.

[@bigd7355]

I'd rather deal with higher cooling bills than the dust, pollen, and mold that comes into your house through a traditional vented attic. Those have major health effects that most people are too stupid to notice.

[@rayc7720]

I unvented my vented attic 10 years ago with 4" of hi density foam. It has been great. I don't get blast of hot air when the A/C comes on or freezer air in the winter. I do not use my attic as storage so no paint needed, To convert, I fashioned solid foam blocks to stuff over the outside walls to spray against. Just sprayed the bottom of the ridge vent as the opening wasn't very wide. I would have used something like zip tape if I did it now. I can work up there any day of the year. It is only a couple of degrees from the living space below. The leaky roof is not an issue. I have a metal roof and even if I didn't and I let the roof go for 40 years, I could just resheathed the roof over the existing plywood. I live in upstate NY and did this when the old experts said it was a mistake, and now today it is the preferred method.

[@mikepeek5655]

Ray C , great job but you may leaks since all metal roofs will eventually leak. Them yiu have a mold issue. Just saying

[@imitane]

If the roof leaks and sheathing needs replaced, is it a huge pain to have it “glued” on with closed cell foam? I guess it’s no match for a reciprocating saw, but then it would need to be re-sprayed afterwards?

[@neverknow69]

Nope you just sheet over the old stuff.

[@redfirekla]

Yeah same channel proves this is the worst product for a roof kzbin.info/www/bejne/fmfNmnqBhLh0eNE

[@Mostviews111]

I've always hated the idea of a spray foam roof by the time you would notice a leak the entire roof and trusses would be mush

[@gallamine]

@@Mostviews111 in NC, climate zone 4, most ppl recommend open cell for attics. Spotting leaks is one benefit.

[@srt4b]

@@neverknow69 You sheet over rotted sheathing?

[@dhutch71]

During a week of measurements in Mid-June, 2021, my 'traditional' attic in Spring, TX (North Houston) averaged 4 degrees hotter than the outside temperature (measured in the shade). The max differential was 9 degrees at 7 PM. The temperatures were measured from 7 AM to 11 PM. Mid-afternoon outside temps were 95-96 degrees. There is radiant barrier sheathing, ridge vents, continuous soffit vents and one solar powered Attic Breeze exhaust fan in the attic space.

[@ashinch0r]

BS

[@jayworley1583]

Matt, love you videos, but for most people / builders, spray foam insulation will remain a pie in the sky scenario due to its high price. However, I do think LP Techshield + R13 or R19 in your roof rafters with a 2" air gap would be sufficient for an "upgraded" home in terms of its attic insulation, IMO. Then, get your ducts sealed /& stretched out really well over your ceiling joists with blown-in insulation over them. Finally, make sure your HVAC unit is in an insulated room / closet and add a QuietCool attic fan that operates at 70 to 110 watts to remove any excess heat. Good ventilation is also key, of course.

[@1ronhall]

As a non-trades person, but an enthusiastic home owner, I’ve always thought our traditional attic build methods was very underwhelming and both the sheathing materials and roof insulation always just made more sense. Thanks Matt!

[@djoflaeyjan]

By rerouting some of the vents and piping you could make extra bedrooms or a large hobby room in the attic. This has become quite popular in Scandinavia with attics and basements, often making enough space for a studio apartment.

[@msheart2]

That's very normals in most of the northeast.

[@CaedenV]

A few years ago I re-did my attic in probably the largest home improvement project I will ever do lol 1950s house, and the attic was finished in the 1970s, and the thin drywall and cheap wood panneling was falling apart, and it was always hot/cold up stairs. Gutted everything except the framing, then added a spacer on the roof line, then a radiant barrier, then batt insulation, and then thick drywall. It changed so much! Still need AC units in the summer, but much smaller units keep up well even on medium where we used to have much larger units on high all summer. Things are quieter, cleaner, less humid, and everything is working really well. Next step is figuring out something for the AC/heat up there. Heat rises, and that is the only place to escape to, so it stays comfortable in winter, but there is a lack of air flow/exchange, and during the summer AC is absolutely required. The rooms all have HVAC supply vents... but no returns. Our HVAC is from the late 80s, and it is kind of a miricle that we havent had any issues with it yet, so we are saving up to replace it as the next big home project... that that will be a doosey, but I wont do that one myself. Hoping to move the HVAC to a different location in the basement (what use to be a garage that is walled off), and re-route all of the supply and return vents in the whole house to make more sense and work better. Should be the last step of 'functional' changes to the home before we go nuts with purely aesthetic changes to finally make our old 1950s wrecker look as nice as it feels to live in since I have done so much work on the electrical, insulation, and water management aspects of it. We have the biggest home on the street, and the lowest power bill, but we keep the house at 70* year round while most neighbors keep things at 75 in summer, and 60-65 in winter. Been a lot of work, and it is nice to feel results. Cant wait to make it look nice and 'see' the results.

[@NICKRITZER]

Thought about doimg spray foam for my tiny home...pretty sure after needing to spray paint...i think i'll just do traditional insulation.

[@brad7358]

one usually does the spray foam for a few reasons....and one is to lower the electric bill. we did this to our first house along with other things and our bill dropped from $300 to $150. other things that were done were new windows and ac....but having an attic that doesnt reach high temperatures is going to save you money each month. we recently sold that house and bought another one and we are going to do the same thing again with the spray foam.

[@chad3076]

Yea, stick with fiberglass. Spray foam is fast and easy but you're paying WAY more for it.

[@brad7358]

@@chad3076 define WAY to much ?

[@davidbartoo1658]

I converted my attic from poorly insulated & vented To a fully insulated at the decking. Vacuumed out all the cellulose and fluffy white. HVAC and ductwork all inside conditioned space. I included a dehumidifier into the air plenum. Very comfortable easily keeping relative humidity 48-55%. 1600sq ft with a two ton 2stage split system easily keeps house at temp settings of 72-74. Even when temps are well above 100degrees. North east Texas area near Tyler.

[@trevor61396]

You should definitely cover the importance of having ERV in a sealed up house. I’ve heard a few stories of people sealing up their house and ending up with unsafe accumulation of carbon dioxide because there is no fresh air coming in, which can have serious side effects.

[@swingset1969]

Radon is an issue in homes like this too in some areas.

[@bob11xx]

I did an addition in 2008 in upstate NY and wanted foam in the walls and roof deck. I never understood having outside air flowing thru the attic. I spent numerous hours talking to manufacturers, vendors, contractors, and installers. No one could/would give an answer. I went with a closed cell foam and have been quite happy with the results. One thing I worried about was the closed cell being non-porous and would hide any roof leaks but so far I haven't seen any signs of damage. I had the contractor run ice/water shield on the whole roof for peace of mind. I do find that carpenter ants love the stuff. I do not believe it is moisture related as I poked around the area and see no signs of water infiltration anywhere around or below the former ant home. One regret is I didn't have the knowledge at the time to use a radiant barrier on the roof.

[@SlooFoot]

I think what would be even better would be to build a house around this house and then condition that house as well as the original house so that the power bill on the original house is lower

[@rockjockchick]

Lol

[@DonTruman]

Nope, too expensive. Better to build a smaller house inside the existing house.

[@McTwistedTwisties]

@@DonTruman yo dog I heard you like houses

[@davidtyndall8880]

Why aren't you using "saddles" on the flex duct strapping? You know that over time the web strapping will crush in on the flex ducting and restrict the air flow.

[@RevolverOcelot79]

Agreed

[@HandlesAreDumb_111]

Guessing it's not the flex that you think it is? They make insulated rigid duct that looks identical to flex until you press in on it.

[@terryherrera5252]

BUT !!!!!!! This attic !!! I never above 80* !!! My problem is COST !!🥵

[@joejohnsonvt]

Matt, a cost comparison would be very helpful for you to include in this video, the cost to do the older type of vented attic vs this new type of conditioned attic you showed us in these 2 houses.

[@scottielewis5136]

Alot. That's why he doesn't mention it.

[@Engineer10211]

More expensive, yes, but you gain conditioned storage and your power bills will be much, much lower.

[@Kevin-ib4gv]

@@Engineer10211 That has to cost $$$$ to construct. You still have to heat and cool the attic which is an additional space and cost money to do it. I don't know how much you save 6 months (3 summer 3 winter) when the bills are the highest, maybe 500.00 a year? I'd say 6 to 8 grand for the work maybe? 10 to 15 year break even? I'd love to know the figures.

[@Engineer10211]

@@Kevin-ib4gv very quickly: The savings can be a LOT more than $500/year, depending on how well the attic was already insulated. Ours was. You can have a smaller HVAC system, again saving money. The system will last longer, too, because it runs a lot less. You gain a lot of usable conditioned space. I even store my comic book collection in our attic, which would otherwise be a big no-no. Resale value is increased. It's a good bit less expensive to do as a new build. If you're handy, it can be done DIY, taking your time.

[@kfk256]

@@Engineer10211 Isn't conditioned space directly related to tax assessed? Will this type of attic fall under such category?

[@chrisedward18]

Looks great. Here in South Texas we look at all things depending on budget. So we use radiant barrier sheathing with a combo of poly to keep attic cooler while staying in a decent budget.

[@ddbear8786]

I just got a new roof and changed to a conditioned attic since I have a lot of AC ducts in the attic. Night and day difference, so glad I did it. Now it's 78 degrees in the attic (same as house temp) instead of 120F on hot summer days. I went with 3" polyiso insulation and lightweight concrete tile mounted on battens. The air gap between the tile and battens allows hot air to rise and cool the underside of the tiles -- that serves the same function as a vented attic. I was originally going to put mineral wool between the rafters in the attic as well, but because of the good performance I will probably skip that step. With modern insulating materials (polyiso) I think it's crazy to design attics the old fashioned vented way. Another benefit I didn't think about originally - closing off all the vents will prevent termites and insects from flying into the attic.

[@MommaARA]

and mice, birds, bats, lizards from nesting.

[@troykinnison4575]

@@MommaARA rats an mice an birds need a safe warm protective place to live slso dont they??

[@OregonOutdoorsChris]

I'm glad you mentioned that zender thingie at the end because I was really wondering about how air exchange is handled. Because otherwise a really tightly closed up building is going to have a build up of CO2 and get uncomfortable fast.

[@fepeerreview3150]

One of the ideas that Matt is promoting and which you find with systems like Passivhaus is to build the house really tight, and then design in a very good ventilation system. This will keep the air in the house healthier than outdoor air because the ventilation can filter out pollens, dust and pollutants, and maintain a good humidity level. Also the ventilation should include heat exchange. This kind of ventilation is becoming more and more common in good quality newly built homes. And of course, weather permitting, we can still open the windows.

[@chrisgriffith1573]

These building methods are going to be really nice for high ceilings in open living spaces, giving the R value it needs while making the interior a georgous space to look at... I really like the idea of having a conditioned attic for storage too!

[@jonathanlanglois2742]

That's what my attic looks like, but I'm further up north, and my ducts are in the basement. We had a water leak with our roof and if anything, the fact that the attic is properly vented is what prevented further problems (by allowing everything to dry properly).

[@finalf137]

If you're looking for any existing houses to do a conversion to unvented attic on, I'm in Round Rock and would gladly volunteer as tribute.

[@finalf137]

Thanks Matt for the like! Really serious, I have a 4500sq house, built in 01’, super leaky/drafty, all three 3 old r22 ACs (1, 2, 2.5 Tons) in the attic. Upstairs attic access through ladder & walk in door. Upstairs gets way too much heat gain from the attic, you can just feel the difference walking up the stairs. Both up and downstairs have high humidity in spring/summer, ~60-65%. The solution I’m looking at is spray foam/seal the attic (suck up all the fiberglass, bug, droppings), but then all the appliances will need to be swapped out for sealed combustion or maybe switch everything to heat pumps instead. If going to heat pumps I wonder if I could replace the 2 of the AC for the 1st floor into 1 heat pump zoned. Both handlers, supply and returns are right next to each other in the open attic, add a whole house dehumidifier in there as well. Totally willing to shoulder the burden on the costs, the savings on my electric bill alone would quickly recoup the project costs I’m sure. It would make a great retrofit home before and after results video. p.s. If I was going to spray foam an attic with vented soffits (Two 4 inch wide Hardie boards with a plastic perforated hole channel down the middle). Would you recommend replacing those existing “vented” soffits with solid soffits, or leave in place and just put foam boards behind it in the attic so the spray foam doesn’t ooze out the vent holes?

[@ronwalsh]

I have a house built in 94, and has zero insulation in the attic space. I was all set up to have a guy do it, but he got hurt and closed down his company. I have been in a search for a company to do it. I would really like to get my attic space sealed up. If you need a house to do this on for a show, mine is available. Thanks for posting this.

[@tylersmith293]

That’s great if you’re building a house with a high budget. But what about everyone else?

[@xcyron]

Rockwool is cheap, you will probably make the money back in saved energie. Insulating the roof is the most effective way of saving energie you can do in a house.

[@agoniaXdunya]

What are you even doing here, pheasant.

[@richardroy61]

I used spray foam insulation when I built my house 14 years ago. At that time the cost was about 3x the cost of traditional insulation. However, in real world numbers, I got the difference back in the first 7 years.

[@sw3604]

Get a 3d printed house then.

[@AD-1138]

Think of it this way, would you rather pay more up front or A LOT more over the life of your house? I mean AC systems are expensive! Why spend the extra $$ on a central AC and not just do cheaper window units?....that you will have to replace a lot sooner than a central system plus you now have more of them to replace... It all boils down to where you want to spend the money.

[@jeffreymcdowell3024]

Hi Matt, I am a Dallas resident in a 1980s home. We will be having our existing insulation removed, air gaps sealed, and new 17" of insulation blown in. One thing I have not seen from you is how to convert an existing Vented attic into an Unvented one, including cost comparisons with just adding new insulation. Feel free to reach out and use my house as a demo :)

[@JimMcGuigan]

Ken is great. He really knows his stuff.

[@trex2092]

Love my ICF house with my sprayed attic, cool enough to keep Christmas candles in the walk-in storage up there, and I don't get that initial blast of HOT air when the HVAC unit kicks on.

[@AD-1138]

Yeah, saw this and hoping to use this IF I am ever able to build a new home. I will def save up for the initial up-front cost of this.

[@imolazhp11]

Love the idea of a conditioned attic, I just wish there were companies out there that would convert existing attics to conditioned attics. Building a new house isn’t a solution for most of us.

[@Engineer10211]

There are. Get the roof deck and gables sprayed with HDPU foam up to the r-value needed for your region. It's called "encapsulation." I retrofitted the attic in my 1950 house in Texas and it is glorious.

[@imolazhp11]

@@Engineer10211, that’s great. But it seems like a retrofit these days requires the owner to act as the contractor, and manage subs. Spray foaming the attic is only one step. Then an HVAC company needs to come in for ducting fresh air, general laborers need to come in and remove blown in insulation and deck the attic. A one-call, turn-key company would be nice. It’s a business opportunity/idea for sure.

[@Engineer10211]

@@imolazhp11 The fresh-air ducting isn't needed after encapsulation unless the rest of your house is extremely tight already. That said, if you have a gas furnace or water heater they will need to be swapped for direct-vent models but you can probably re-use the roof penetrations for those. I know that insulation companies in Dallas will remove old insulation. And oh yes, I modified my gas dryer to be direct vent (don't tell the inspector) with coaxial venting and a plenum on the back of the dryer. But if you want a sweet setup with a floor, yes, you'll either need to DIY it (or at least a lot of it - I recommend getting a sub for the spray) or hire several contractors. My wiring was running on top of the ceiling joists, so I drilled through the joists and re-located it (I'm a structural engineer, so no problem getting it right). So that's an electrician. Decking would be by carpenter (I did my own). If your ducts are all over the place like most are you could hire hvac to tidy things up or do it yourself. It may sound like a good business idea to provide a turn-key project, but it's hard enough to sell people on the idea of investing maybe $7 or more per sf to just spray their attic. Doing all the other stuff would probably push it to $15. There aren't going to be many takers.

[@KN-jr6tx]

@@Engineer10211 Is your estimate of $15/sqft inclusive of all costs for the conversion? Also, is that calculated by the floor area or the surface area of the inside of the roof and walls? Thanks!

[@Engineer10211]

@@KN-jr6tx I'm totally spitballing that number, but it would be based on the square footage of the attic and yes for the total conversion. So converting the attic of a 2000 sf (one story) home would cost $30,000. That is just a really rough guess. An attic floor isn't going to serve much purpose where there isn't enough height to use that space so the floored area would be smaller than the house footprint. The spray foam would have to be on the entire roof deck and that particular cost would be calculated from the sloping area of the roof, not the horizontal projection.

[@Bob_Adkins]

Back in the day, insulation in direct contact with roof sheeting was a no-no because the shingles get too hot. A space for passive venting kept the shingles a little cooler.

[@3beltwesty]

The shingle roofing literature mentioned one had to have a vented attic so the shingles say cooler or the shingle warranty was void. The buidling codes too also had plans reviewed to check the number of soffit vents and top vents so the attic was vented.

[@fepeerreview3150]

It depends on the shingle manufacturer. GAF provides warranties even for unvented roofs. Tamko doesn't.

[@toddcunningham3213]

Our local codes require it. Plus, I don't think the way the attics in this video are framed would pass snow load requirements with 2 x 6 rafters on 24" centers and no strongbacks. We typically use 12" TGI engineered rafters for applications like this, but the joist space is still vented.

[@thomaslamb3119]

From an energy savings perspective it’s great. From a termite perspective it’s awful! Currently we have been advised not to fumigate houses that do not have ventilated attics. Additionally I’ve seen homes where termites get in between the foam and the sheeting and do tens of thousands in damage before you know.

[@TheMax13542]

energy savings on these houses isn't a real thing. If you add the attic to the conditioned space your increasing the cubic volume to cool and need to increase the size of the hvac system.

[@MariuszChr]

@@TheMax13542 it's getting balanced by overall much more superior insulation.

[@Goldarr1900]

It’s like reinventing the wheel. Some things are better left alone.

[@sunriseshell]

@@Goldarr1900 And some times NOT leaving things alone brings innovation. I don't like the "If it ain't broke don't fix it mentality". This stifles progress and innovation. With that mentality we'd still be walking and riding horses everywhere.

[@hailexiao2770]

@@TheMax13542 It is a real thing if you have HVAC equipment and ducts in the attic, which is admittedly a stupid thing to do.

[@mwgrc]

I'm not going to give it a thumbs down, and will give you Kuddos for thinking outside the box but off the top of my head its adding more tonnage to the HVAC system, more to heat/cool, ceiling joists now need to be load rated as floor joists, a remodel to make this happen would be a nightmare of MEP"s to rework with bracing issues throughout on anything over a 6/12 pitch, and not that you would necessarily get caught, but these Texas Property Tax folks would place a pretty penny on that mostly unused yet conditioned space. But I did find the idea interesting, and liked the Pro's you mentioned, I just don't see how this could possibly be cost effective outside of new construction and I'm iffy on that.

[@bradlyfkennedy]

Hello Matt! Thank you for the videos! My house was built in 1997 -- I live in Dallas -- and would like to use Rockwool in-between the attic ceiling rafters like you did in the above video. My question is, did you do a vapor barrier between the Rockwool and the inside attic roof?

[@johnlee7085]

On Matt’s house, he used zip sheathing and a double layer of insulation board and more on the outside so his vapor barrier is outside.

[@dumbdumber1885]

Which would you rather have for a roof, engineered trusses or rafters ? Engineered trusses allow you to open the area below. Rafters allow you to open the attic which you can convert to a living space or "condition" it which is what they are doing here. As for the foam I wouldn't bother, no way it's less expensive than dry wall and you can't tell if there's enough or if it's covered properly etc. You can see drywall and you can vary the thickness and you can add metal fairing channel for a little more sound proofing etc. If you have trusses and your attic is hot in summer consider adding insulation between each truss at the roof line. I think I might try that.

[@adambert3042]

I’ve done the same thing with batts and I only use spray foam if it’s the only way to insulate the particular job or if the client insists. The jury is still out on what happens to the plywood that’s above the insulation if it has no air flow or if it’s sealed on the cool side as with spray foam. That’s why I prefer batts up against the roof deck but with fluted baffles connected on the down side by a vented soffit and on the upside by a ridge vent. This allows some air movement between the insulation and roof deck thereby reducing a little bit of the heat build up. Great video but I might add too that the depth of the trusses will determine the depth of your insulation in turn the R value of the insulation. The video shows R30 therefore you’d need a minimum depth of 10” to allow for R30. This would be a special order truss if you’re building new or you’d have to fur down the trusses. Great video Matt. Keep em coming!

[@AlexRamos-nz6dj]

As a telecom worker, if there's no conduit/ surf tube that goes from the outside utilizes to the attic and/or smart panel, the chance of drilling the ductwork and tubes is really high and not good. The foam makes it difficult as well to see where the line is without completely destroying the insulation. I highly recommend a conduit, especially in fiber neighborhoods. The floor boards make wall drops difficult as well. Love the attic though, I would make sure to run all the cat6 and coax lines to each room where the TV, gaming console, and computers would go.

[@nholt]

So there is a vent up there with cold air coming out? And heat in the winter?

[@amyschwebke4007]

Purchased our retirement home (built in 1947) - roof is currently a mix of normal pitched roof and some flat roofed areas. Will be installing a brand new metal pitched roof where trusses will be built onto the flat roofed locations so that all the roof angles are same-same (rain gutters to water barrels for gardening needs). I'm thinking the DC315 spray foam would be the best option for the new roof trussed areas. Would love to see a retro-fit video of an older house being updated with these new insulation techniques.

[@froissart1]

Is it possible to move from a vented attic like the one you were in at the beginning to an unvented? How does one remove the trusses?

[@Egleu1]

Trusses are structural you can't remove them without changing the roof joists to 2x8s or something.

[@jaxturner7288]

@@Egleu1 nah shucks, just sawzall the old trusses out of the way. Totally not needed anyway. Easily a DIY weekend project.

[@kipwilson3771]

You start by using real trusses and never using pre-fab pixie styx.

[@jaxturner7288]

@@blaydCA that’s brilliant! Well, obviously a professional has entered the chat. Quite please, I want to hear this.

[@jaxturner7288]

@@blaydCA does that mean I was fooled? Are you not a real pro builder guy? Because I don’t think we can set this guy as the standard to meet as a pro can we? Maybe as a standard for a professional from California?

[@mahamasamataman3087]

Greetings, I have recently acquired a new home with a detached garage. The garage is 2x4, OSB, and vinyl siding (not tyvac -- yet). The "attic space" is open engineered "A" frame. Soffit vents, ridge vent and a gable vent on each end. I have temporarily closed off the gable vents and installed a portable AC to try to drop the humidity (which seems to be working). I figure that I will need to remove the ridge vent; but not sure what to construct in its place. I have yet to figure out what to do with the soffit vents. I have plowed ahead and purchased enough R13 faced fiberglass batts to put up between the roof rafters (24" spacing). I would like to spray in some mold/mildew inhibitor before putting up any insulation because the garage has been sitting at ~80% humidity for years... Lastly, I am considering having solar panels installed which I figure will also reduce the heat in the garage as it will shade the roof (I used a FLIR heat imager and found that the roof is BY FAR the greatest heat contributor). The ultimate purpose would be to serve as all of my shops: woodworking, auto working, electronic, metal working, and the like. Thoughts?

[@NoBody-ro3xj]

Install big ass fans in your shops they work well with humid places :p

[@tobiasnachname6358]

Nice to see that the US is slowly adopting the standard we have had in Germany for 20 years :>

[@dryfly2000]

I agree the typical American home builder doesn't"t give crap about efficiency. Nothing here has changed much. I wrapped my house with Tyvek 5 years before builders began doing it here in Salt Lake City.

[@mfam2371]

Yea glad to see Germany adopted the standard we had back in the 40s

[@seanbouker]

In the north where I live we have lots of "Cape" style homes... for the un initiated; a cape is a ranch or salt box 1 bed 1 bath home on the main level that has stairs to the attic which is pitched as an upside down V more or less... Not leaving much in the way of useable headroom... Most of these get Dormered out or expanded to create more space and add a bathroom... Slap up some sheetrock & fiber batt. Call it a day.... Toss the kids bedrooms up there and call it a 3 bedroom house..... In the summer the space is near un liveable. The added moisture from an extra bathroom and the fact that most people don't understand how thermodynamics works.... Mold and saggy sheetrock is common. When it's conditioned since it's not a sealed space you can imagine the outcome.

[@conquerordie230]

Have building codes been updated to include these kinds of attics? I would imagine that there would be a substantive amount of pushback from inspectors as soon as they don't see something they immediately recognize or are otherwise use to.

[@thomaslbane]

It’s permitted in the code. Has been for a long time.

[@MariuszChr]

Yeah, "I never seen something like that. Redo it the right way" lol

[@hailexiao2770]

It's been in the building codes for at least 25 years. No inspector is so backwards as to reject spray foamed roofs.

[@steelyspielbergo]

it's basically a story-and-a-half house.

[@TheCraftsmanBlog]

What do recommend for retrofitting insulation in an older home. Like 1920s when you don’t have a sealed attic but want better thermal performance.

[@zilfondel]

Look into air sealing and then adding cellulose insulation. It's dumb, but it works. Blow in cellulose is better than pink batts.

[@kswas2784]

I understand you have a metal roof but if your roof is standard shingles, the shingles need to permit some heat to pass through. If you insulate right against the plywood roofing sub-straight, that heat will be forced back to the shingles and cause them to dry, crack and edge curl greatly reducing their lifespan.

[@dfhgj1022]

9:13 - what connectors do you have on the tank and the torch? any regulators at all?

[@onjofilms]

I knew someone that did a commercial install of closed cell. I asked how do you know when there is a leak? They said they had one, it built up water until it busted like a balloon onto the floor space.

[@safffff1000]

Flat roof or sloped? Failure of roofing, was the wood all rotted ?

[@drewcipher896]

Even a small leak has no chance to dry out stuck between the roofing and foam. It's just going to rot the wood between.

[@safffff1000]

@@drewcipher896 spray Jones has been doing for 30 yr successfully.

[@repetitivemotion]

I build in the suburban Chicago market. We are doing foam insulation exclusively and of course the foam is blown onto the underside of the roof sheathing and in between the rafters. It’s expensive though.

[@DuncSargent]

You need to be able to put your model railroad up there too!

[@redactedinformation2813]

Non vented roofing system is Florida is a disaster of epic proportions. The USDA attempted this in tampa on several residential new construction sites. Less than a year and the homes are unlivable due to mold.. great job reinventing the tried and true vented system..

[@davethompson16]

You are forgetting the reason for vented roofs is air flow to eliminate condensation. While you may get away with this in warm temperatures you still risk shingle life and rotted sheeting. This would work fine if you incorporated a dry deck roof system. I have personally repaired several roofs from the rot of an incomplete system as you are showing. It is a fantastic system if you take care of the condensation.

[@douglasberger2425]

Vapor permeable membrane under ridge vent allows moisture to escape. Plus the air is constantly being cycled using HRV equipment. Your dining, or bedrooms don’t have vents. The crawl space and attics being treated as conditioned space are working at being more energy efficient. But they will need electricity.

[@ChiBr33zy]

I would hate to be the roof that might have to replace bad roof sheeting if a leak forms. That spray foam seems like a good idea, but its makes changing out bad wood a complete bear to replace.

[@aintquitewright1480]

Show us some FLIR video of these attics on a hot sunny day.

[@davidhoover2446]

I have a flir. Pretty cool product. On a hot sunny day in FL with radiant barrier my attic runs 100 degrees. A lot better than our last houses.

[@aintquitewright1480]

@@davidhoover2446 Yes. I got the FLIR attachment for android. Texas 110 outside 129 in attic before radiant barrier, now the attic is about 3-4 degrees warmer than outside ambient. Keeps my duct work in the attic much cooler.

[@xanthanx]

@@davidhoover2446 100 degrees is still way too hot.

[@lucphinney]

Just to clarify ... Are you maintaining a vent space between rockwool and roof sheathing? I'd worry about dew point condensation migrating to the underside of your sheathing and causing rot.

[@chrismartindale7118]

Mike recently addressed this issue using a venting/moisture barrier at the ridge vent. I found this video very interesting as well: "7 Keys To A Better Metal Roof Install"

[@huntermac8970]

What's the cost difference though? I'm guessing it's substantial.

[@ironDsteele]

This is not in your average working class family's buget. Spray foam on the bottom of a vented attic but not the roof sheathing is always an effective and economical option.

[@mattfrick8038]

This is done when budget is secondary to wants.

[@CaroAbebe]

In my country, it’s obligatory to build attics so that they keep out both the cold and the heat. The cost? Of course it’s substantial, but in the long run, you save on air conditioning and heating.

[@oHITMAN14o]

In my home we did spray foam on all exterior walls and the ceiling and the attic in Texas stays at around 80 degrees when it’s like 100+ outside

[@huntermac8970]

Where I live, all of the mechanicals go in the basement. Without all those penetrations into the living space from above, it's really easy to get fantastic insulation numbers in a vented attic. Only reason we build a hot roof is if we are using it as living space.

[@tha073926]

Could you convert a non conditioned attic to a conditioned one? I would love to see a video about that or even better an actual example of one being converted.

[@dustinschmelzle7326]

you can but the thing it if the were built not intending to be contained the roof structure may need to be redone to make the space navigable

[@KpxUrz5745]

Would be nice to explain approximate costs of this attic construction (with that very complex air handling with vast numbers of flexible venting pipes) versus the typical loosely insulated attic. I suspect it is prohibitively expensive for most people. I also suspect that in many areas it would be difficult to find a contractor capable of this more advanced type of attic insulation.

[@Moondoggy1941]

If they do not talk about price then it is way to expensive for most people. They could easily do this in So> Cal in the fire areas, most of the fire insurance is going up 900 percent.

[@williamw2529]

Thats a thing of beauty. It's like theres a right way and a wrong way of doing things, and most of the industry does it the wrong cheapest way possible.

[@kenyonstewart7120]

Hey Matt, It would be nice if you could cover a framing, insulation, and barrier package for a vaulted ceiling build with no attic. In CA, many homes are pier and beam, so ducts are under the floor instead of in the attic. Vaulting a ceiling is a common home renovation request.

[@mikedandar1171]

I think that would be good for CA, especially with the fires you have out there. An unconditioned, vented attic could easily draw in embers from a fire, whereas, if the attic is conditioned and sealed off, there is no way for the embers to get in the attic. 👍🏻

[@johnlee7085]

The only difference between a vaulted ceiling and the attics shown is the extra framing for the ceiling and the location of the wall finish. Ooops, ductwork too. The insulation is the same.

[@davidmiller716]

I've seen good designs where the HVAC is in a closet in the conditioned space, ducts in lowered ceilings in hallways, and fake beams, or between floors. All of the benefits of a conditioned attic without the concerns of needing power to dehumidify that space.

[@xnavynuc]

This is great if you have a tile or steel roof, but if you have asphalt shingles you better check your warranty because many shingle companies won’t cover damage or reduced lifespan caused by excessive heat the shingles experience if the under side is insulated instead of open to air where the heat can dissipate.

[@1bottlefed]

Hello Matt, The name of the property that coating is exploiting to reduce heat transmission to the foam is "ablation" . An interesting fact is this same technology is used on spacecraft to protect the craft and passengers on re-entry.

[@paulo7200]

The rockwool just looks nicer.

[@thomaslbane]

Costs more, though…. So does the framing…. Especially if you use SPF (double-so if using intumescent coating)…. Oh, and the roofing won’t last as long because it gets hotter with insulation beneath it… And SPF prevents drying to the interior so small leaks in the roof are a MUCH bigger issue because the water gets trapped between the impermeable roofing and the SPF. So, yeah, it’s “better”…

[@jakebredthauer5100]

@@thomaslbane Maybe Matt "needed" to publish a video and didn't have time to think it through. What about cost to build, cost to maintain and cost to operate? More flooring, more stairs, bigger door, difficult insulation installation, more difficult shingling a high-pitched roof.. He should do another video addressing the issues you identified.

[@27photogger]

Thomas Bane does it really have heat issues causing roof leaks sooner since the roof can’t breath as well with the spray foam ?

[@jakebredthauer5100]

@@27photogger Asphalt shingles are sensitive to heat, steel not so much.

[@harryclark5108]

Where can the code requirements for the foam insulation thermal barrier be found for South Carolina. My county subscribes to the ICC codes, but they are only available if you pay for a subscription or PDF. Seems like that kind of information ought to be publicly available. Many thanks for the video! Nice job.

[@68Jaguar420G]

And how does all of this affect the roof finish, be it asphalt shingles or metal panels?

[@RobertTorres27]

As long as proper air gaps are accounted for when installing the roofing material, the finish would be the same.

[@68Jaguar420G]

@@RobertTorres27 And that is exactly my point! Nothing has been said in this video about an air gap under the roof sheathing allowing venting from the soffit to the ridgeline. If anything certainly the spray foam has been represented as adhering directly to the underside of the roof sheathing and it seems the batting was also directly in contact with the roof sheathing. And if that is the case then you can expect the roof finish to degrade pretty quickly, especially asphalt based products. I like a lot of the videos Matt puts out but but this one seems quite incomplete by not addressing the roof deck ventilation issue. And not everything he presents is gospel truth. For instance he came out quite strong in favour of "flash and bat" insulation which has now been quite soundly debunked by a lot of people in the insulation business. I'm reserving judgment on this video until more information is forthcoming

[@pcno2832]

@@68Jaguar420G At 3:18 he mentions that the space between the metal roofing and the roof decking is vented. That's not a full explanation of the issue involved, but it's at least an acknowledgement that they exist. This really calls for a video on the pros and cons of this kind of venting verses a "hot roof", if anyone is still building those.

[@thispandaispurple]

Metal panels don't give a damn about anything, venting or otherwise. Shingles although need enough ventilation otherwise the furnace effect can bake and make them crumbly.

[@RobertTorres27]

@@thispandaispurple Not necessarily true. Without a proper air gap, moisture from condensation on the underside of a metal roof or driving rain won't be able to fully dry out, resulting in premature degradation of both the metal panels and the underlayment/sheathing.

[@carrtb]

I had my house built in 1993. The attic was exactly as shown in the beginning of the video, vented and unconditioned. I quarreled with the logic of having the HVAC suspended from the roof in the attic every time I went into it in the dead of winter (-6 Deg F or more outside, hence frigid attic) and the heat of summer (over 100 typical outside, hence unbearable attic). Plastics (automated duct equipment housings, motor gears, etc) aged and failed quickly. For years I looked for solutions to avoid operating the furnace in the worst possible environment in winter and the air cooling operating in the worst possible environment in the summer. I began looking in earnest after 19 years when I knew I was very close to needing total HVAC and condenser replacement. I did with a company which vacuumed out all the blown-in insulation and spray-foamed (closed cell) under the roof. They also sealed the attic with the exception of two vents. Apparently this was a requirement (at least in 2010) since my heating is accomplished with a gas furnace. It cost $10,000 for the re characterization but I’m very happy with it. My winter heating bill cratered from the previous years highs. I replaced the HVAC system after this when I knew the system would be in a much better environment. Now my worst month’s heating bill is 1/4 of what it used to be and the worst month AC is almost half. I have a question, since my attic has no living space and is now “passively” conditioned, are the remaining two vents still required? The furnace has a coaxial venting system, the combustion air is drawn down through the outside corridor and the exhaust is expelled through the inner corridor.

[@craigmellott6339]

When I hit the lotto Matt will be building my next home

[@RemmikRotus]

Hopefully it would not take over 2 years :)

[@judefuselier]

When I hit the lotto I'll be building my own house

[@phlg]

I do HVAC for a living in Texas, I wish attics looked like that, they are the bane of my job.

[@kenmaira]

I'm amazed at the condition of the way the stretch duct has been done, those are some beautiful bends, instead of the atrocious corners I see when people hang it down.

[@ArthurDentZaphodBeeb]

Well, when you know your work is being seen by hundreds of thousands of people, you can bet best workmanship is at play.

[@kenmaira]

@@ArthurDentZaphodBeeb Very true, but at the same time, I'm happy when at least one customer gets to have a properly installed AC system.

[@ThePurplePupUwU]

One day, when I have a good paying job, and am ready to own a house in 10 or 20 years, I want to have the home built brand new, according to the specifications I want, I'm going to hire you for that project, I've loved all of your projects!

[@pastmasterdan4080]

I’ve seen some SIP construction that didn’t require any vents and a small hole allowed for environmental exchange between upper & lower. Fantastic insulation by the by.

[@MrPhatties]

Looks like a good option but how does it hold up in -40 degrees with 5 month winters?

[@countryironforge4275]

Right, wouldn't fly in manitoba. The frost build up under the roof would be horrendous

[@MrPhatties]

@@countryironforge4275 yeah I don't know if it's even code compliant here since you need vents under the roof decking to prevent ice damming and condensation build up inside the roof structure. I've only seen it on steel frame roofs like in industrial. Not to mention you're almost doubling the surface area (and heat loss potential) by insulating the entire roof vs the attic footprint.

[@hailexiao2770]

You'd probably want at least 6 inches of spray, and definitely encapsulate all the rafters. Once you do that there won't be enough heat reaching the roof to cause ice dams, and since 6 inches of spray foam is a Class I vapor barrier no moisture will each the roof deck either.

[@michaelmansour6326]

What happens when the roof, flashing etc. starts to leak after so many years? It just rots the heck out of the osb roof sheathing and no one notices it? I understand it wont drip through. Sounds like a recipe for disaster??

[@justinlassiter7671]

he most likely has an impermeable layer on the roof decking between the metal roof and sheathing. it can only leak where fasteners penetrate. from there you just give the water a place to go.

[@fepeerreview3150]

Probably shouldn't be waiting for leaks to rot through your sheathing and start staining ceilings. It would be better to inspect the roof yearly and replace/repair flashing before the flashing fails. In short, routine maintenance can save a lot of cost and headache down the road.

[@benjamindobalina7493]

@@fepeerreview3150 Explain how if you have to do "Preventative yearly inspection" on your wood deck, sandwiched between plastic foam from underneath, and you shingle or metal, (especially the latter) on top, without ripping one or the other off? just curious

[@fepeerreview3150]

@@benjamindobalina7493 If you'd like to know more about how to inspect roofs and flashing you can learn far more about it from studying the material available a NACHI, which is the Association for Certified Home Inspectors. They've got lots of good material there. I'll link to one of their articles. There is plenty more. In my previous comment I had in mind all the visible flashing elements, gutters, roof-to-chimney, vent penetrations, etc. Those are always the most likely spots and the first to go. Look for signs of corroded GSM, poorly done caulking, things like that. If those visible elements are checked regularly, that will prevent a lot of common problems. Most people don't even bother to clean their gutters often enough, let alone pay attention to the roof. "Out of sight, out of mind" is very easy with a roof, and sure to lead to costly problems that could have been caught and dealt with much earlier and more cheaply.

[@ernieforrest7218]

Well Matt conventional roof rafters have been the standard method in many parts of the country since the founding of the country. Difference is however it takes more skill to layout and cut rafters on site than it does to order engineered trusses from a factory. As for the insulation, contractors can only use what is available, and that has changed over time.

[@schtinerbock4570]

unfortunately that will NEVER become standard with our current builders unless it is mandated which it never will be.

[@xythiera7255]

American hows building yikes .

[@alfredhermansen4787]

He never mentioned the cost. The average American can no longer afford to build a house as it is, much less one built with a new mandate requiring an attic like either of these.

[@ffbuilders8139]

Never say “never”. Energy/building code is constantly changing. 10 years ago most people would say the same thing about requiring solar. Yet here we are. California mandated solar on new residential construction in 2020.

[@jolandafrijlink6103]

As a dutch person and daughter af a builder i think americans houses are flimsy and not durable.

[@jeffraber9110]

@@jolandafrijlink6103 I'm sure as a Dutch person and the daughter of a builder you know all about tumescence

[@Aepek]

0:24 Hot, that’s an understatement if ever Matt. Live in Central FL and gotta say, when doing a project and time to get into “attic” crawl space…..we do rock, paper, scissors….or draw straws; no joke. Last thing we wanna do during the wonderful “summer” season here in Florida (or what we call it, “Hurricanes, hot, & hell season”) is have to go into the attic/crawl space and do work. Even makes it worse if gotta gear up with PPE🥵🥵, it’s so bad. The pic here is pretty much the typical style, but so much worse for most houses around “us”. We do get lucky once in while and find an attic area where can actually “stand” a little, and move some what around; compared to the normal slithering on stomach and crawling below rafters/framing, NAILS, ducting, and so on. 1:29 [We] all need to start building houses LIKE THIS; as it’s SO Much better, imo. Can actually have access for repairs, running a wire or something etc…, walking and standing up, and not dying of heat exhaustion…. This is such a beautiful attic 😢, so Beautiful, that wish it was My House. Great Vid, and can’t wait for your hidden door vid of your “real remodel”, as love all your hidden door vids; and b/c if your channel, started using Sugatsune and Soss hinges for doing our own “hidden doors”👍🏻

[@JRMoritz]

Every time our AC comes on we get a blast of super hot air… we are in Central Florida.

[@DTWCT]

Not the best option, but a cheaper one is to spray foam the ducts

[@joannavaldez]

I didn't even come to KZbin for this. But this was one of the most amazing videos I've ever watched!

[@cybermanne]

Great video as always. One thing I'd be interested in when it comes to spray foam is those horror stories of foam that never "cured" and are off-gasing some horrible fumes that makes the kids allergic and sick. It would be interesting to know what has been going on in those cases, and what they did wrong there, and how to avoid it.

[@hsantillo864]

I'm in that mess now with open cell on the walls and roof, plus the contractor sprayed the heck out of everything, the attic vents in the gable, the roof ventilation fan. He claims it's a non venting attic, of course he turned it into one and created a sauna!!! The off gassing when it's hot out is horrible. It stopped my kitchen reno now that we had to pull off the damp drywall and ceiling. Not sure how to best remediate this mess! Need advice.

[@cybermanne]

@@hsantillo864 I have no advice unfortunately. Only condolances. Hope you get it fixed.

[@LawnD4rt]

In Texas, what is a per sq ft est to convert the "Old Style" to the newer setups? Also, the foam directly on the roof decking? What if that decking needs replacing on a future roof install?

[@ronmullen8690]

Good video; what if a bushfire was active; what would happen to the incoming fresh air inlet, would it go into safety mode?

[@marcinkwapisz7752]

It is incredible thing to watch that kind of video in 2021. I am really confused. I thought such insulation technologies are wide spread all along the world. My house was built that way 25 years ago! One additional advice: put second layer of rock wool cross the wooden construction (rafters) to remove thermal bridges. There is 15cm+15cm rockwool under my roof for example (heat conductance parameter lambda=0,033W/mK ), and this insulation thickness is treated as a reasonable minimum now. You can cover wool with drywall and arrange additional space for living.