DON'T INSULATE YOUR BASEMENT until you watch this...

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In this video we will show you how to insulate your basement properly, including the often overlooked under-slab insulation (Did you get the pun over/under...). Anyhow, huge thanks to Architect Steve Baczek for showing off his work and details for the Build Show
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[@mdbohica]

Mr. Rissinger, I am not a builder, I have been thoroughly geeking out on your channel for the last 6 months trying to absorb everything you share with modern building science. I am curious, since the walls are poured before the slab, how do you moisture/thermal-insulate the foundation walls at the bottom and exterior so they aren't a heat loss/moisture-wick?

[@joe4324]

You can wrap the whole foundation in XPS, They should have insulated the exterior, but for some reason they wanted to spend the extra money and time for a less temp stable room...

[@jamesrussell8964]

SunRa l

[@mdbohica]

What?

[@davetaylor8614]

Josh Herzberger , Check out Matt's video on Icf waterproofing.

[@CompCrasher86]

I know you're from down south but I'm loving these segments about building strategies in the Northern climates, they really apply to me.

[@JoniAntonio]

same here...

[@StephanieBacks]

me too, minimum code is R-10 for basements here, and they've already beat it!

[@jamesm.2802]

Ditto. So helpful!

[@ambroulard]

Yeah, Steves awesome BUtT that system is EXPENSIVE.

[@donnievick3076]

So is tearing up old work to do it again.

[@itruck1]

@@donnievick3076 Here's a thought, if your over 30 and you build something that will be trouble free for 70 years you will never really care when someone complains about your work. "Build and live in a house you can afford".

[@chrishuyler3580]

@@itruck1 I own a house built in 1910. The funny part is the only craftsmanship that requires attention is work done in the 70s and 80s.

[@daydatecomplicate9026]

Matt looks like the kid from Toy Story here 😂

[@larrypadilla8706]

Sickest. Outro. Ever.

[@larrymaloney877]

What is the fire rating for the foam? In a foam insulated home, more folks die from deadly foam gassing during a fire than smoke or flames. Again, what is the published fire rating? Also, does that particular foam have a published test showing how it ages? On a personal note, I had a fire in my home recently, and fortunately, came home just as it started burning from a shorted extension cord in my dining room. I had one piece of 2'x2'x1" rigid foam board in the dining room along with two sticks of foam trim, all against the wall. (The product that simulated wood baseboard trim.) The fire was still small so I drew buckets of water from the bathtub to put the fire out. That bathroom is just across the hall from the fire but I had to step outside and BREATH, before re-entering because of all the gassing from that little bit of foam. A houseful of foam would be deadly in an instant! Even my little fire was terrifying. I can't imagine being in a foam home & having a fire. I was lucky to come home and catch it in time. There was little damage from the fire, just my carpet, and sooty walls. But the gasses almost killed my kitty and me. Again, what is the fire rating? Some products claim "will not burn." And truly, the foam doesn't burn. But it melts and off-gasses deadly fumes. What is the brand of foam? And please share brand's fire rating? It's been tested by a third-party testing organization. Where is their report? Please don't be shy!

[@InfernosReaper]

Even fireblocking foam will eventually fail in the heat, so anyone who says "will not burn" is definitely spouting stuff that's misleading at best and an all-out lie at worst

[@Regolith86]

You used buckets of water to put out an electrical fire? Forget the gasses, you're lucky you didn't electrocute yourself...

[@larrymaloney877]

@@Regolith86 , good point, Rego...electricity and water don't mix. My fire was a carpet fire, caused by an electrical short in an extension cord. When I walked in the front door, the house was full of dark smoke. I couldn't even see the flames so I worked the light switch and the power was off. The short had finally tripped the circuit breakers so no electrical current could flow. Besides, I unplugged the defective cord. Again, the only issues were the fires burning is several spots on my carpet and the fumes from the melting burning plastic. I tend to get windy when writing but did my honest best to keep this one short. I hope these details rest your mind. I even used an IR camera to find a hotspot inside the wall. But when I drilled into it I found a was a kitty on the basement ceiling girder below. The camera was showing her body heat not more fire. It was a valuable lesson. I won't ever use trim boards made of foam again. It shouldn't even be available..too hazardous. And I'll finally get around to adding a few wall receptacles to accommodate the new service I installed...no more extension cords. Several years ago I upgraded my electrical service to 200 amps. At that time I relocated the outside masthead and while installing the new meter I added an outside circuit breaker. I have a healthy respect for electricity. I once taught electrical safety as part of an electrical course I taught to electricians, maintenance personnel, and electrical engineers. My next personal upgrade will be replacing the conventional circuit breakers in my panel with the latest electronic versions. Some detect flash, arc, and leakage.

[@refusoagaino6824]

I remember when some wall to wall carpet products were pulled off the market, performing like Napalm in a fire before some insurance company flagged it. That was last century. Polysiocyanurate is the "go to" insulating product now, due to it's high (R 6.6) insulating value and it's ready availability and inexpensiveness. But it off gasses over decades (70 years?) to where it eventually has a low R value. So what is the design life of a building? In my book, they should last hundreds of years, so polysio-based products are out. The only substitute I know of is compressed rock wool. Being organic, it never changes and being compressed, it can be applied in some places where fiberglass can't, like onto concrete and I think, under footings. R 4 per inch means you need 33% more of it. But now we have a crisis; If we re-build all the houses in America properly, not using polysiso products (they are also a petroleum by-product), we have no chance of enough beneficial effect to help with the onslaught of Global Warming. If we use them, we contribute to Global Warming but will at least have some shelters that can weather whats coming. Obviously, we'll do what we have to so Polyiso products will be used predominantly. But the rest of the house is concrete and the design life of other parts is hundreds of years, so why add critical insulation that will fail after 70 years? Stick frame house yes, concrete houses, no way. Food for thought, we'll all be in tents before the end of the next century anyway.

[@larrymaloney877]

@@refusoagaino6824 , With your prodding, I remember the foam carpet that poisoned the homeowners who used it. Foam itself was removed from the market in 70's because of formaldehyde. Today, it's still found in small amounts. But when we mention "foam" it has several meanings because there are so many different kinds. The weak foams, like pump foam, rides on the coattails of the better foams pretending to have similar qualities. Trusting homeowners, who want to believe they are doing the right thing, pay double for an inferior product. They don't see the shrinkage going on inside. High-pressure salesmen have to lie in order to keep the product on the market. Global warming isn't the consequences of poor insulating practices in the USA. IT's the direct result of gluttonous consumption of energy. Besides, there are very adequate, and affordable techniques and materials to retrofit existing homes with excellent insulation. It's just not foam. So don't use global warming as an excuse to burn more petroleum. We have the technology but the profit in foam drives marketing which is contrary to what planet earth needs. Politicians are about creating/maintaining jobs, not doing the socially right thing.

[@kingofl337]

So how do insulate an existing without tearing it out?

[@AbbreviatedReviews]

It's wild how Steve seems like he's not going to do well on camera until he starts talking and then is just awesome.

[@justinclark216]

Its the sign of a guy who's in his environment, and knows his shit.

[@moki7685]

@@justinclark216right on. He is a professional

[@AriOjala]

Good building practice in Finland is to insulate the basement from the outside. We don't have many basements nowadays because it's cheaper to insulate the perimeter of the house with EPS or XPS rather than to build the basement below the frost line. Also post WW2 basements had inadequate drainage so there were a lot of issues with flooding so basements have bad reputation.

[@vickzin]

What if you cannot insulate a cold celler from outside? Any possibility to insulate from inside without risks of mould or moisture?

[@AriOjala]

@@vickzin If I had to insulate from the inside I would leave a vented gap between the wall and insulation.

[@HotNoob]

this. plus... doing a building with eps around the peremiter now. it's like -10*C for a month now... was sprayed -5*C. no heating what so ever, and it's been a constant 5*C inside. i imagine if it was underslab insulation, none of that free geo thermal heat would come through and it would be -10*C inside right now.

[@dongibson189]

Save so many hours of extra labour and material if you use ICF walls!

[@randomstuffwithjoe]

I'm building a new house now. We just finished the foundation. My wife's uncle is doing the site work and he's pushing hard for me to insulate under the slab before we pour in 2 weeks. I've been fighting against it thinking its a waste of a few thousand dollars. This video has me re-thinking my position.

[@nbansal4732]

Always worth insulating

[@dct100100]

I’m a spray foam contractor in Canada and we usually spray foam on top of the grave with closed cell foam it acts as the vapour barrier as well as the insulating factor. The big benefit of spray foaming rather than using insulation board is if there’s any voids it fills them in rather than spanning over

[@robertgregory2618]

But can't it get into the gravel and stop the movement of any water.

[@minutemandefense3935]

@@robertgregory2618 I would think it would only makes its way into the gravel by an inch or two before it sets up.

[@zzzzzzzzzzzzzzzz8635]

I can't imagine that you would ever recoup the additional cost in energy savings over board insulation.

[@MrSprintcat]

@@zzzzzzzzzzzzzzzz8635 think about it your right.the company's get the spray foam in large quantities at a discount then stiff the customers because they can.

[@tableshaper4076]

What happens when the foam starts to degrade????? I don't get it, a foundation should last 150 years at least, that foam is good for 15-20 years... then what. Your foundation will either be floating and weak or completely collapsed... no?

[@WAJK2030]

German Architect/Construction Engineer/Prefab Construction Contractor here. Your videos are very informative about the US construction scene. But surely we wouldn’t ever do, what u guys are praising here. I advice anybody to check out the Eurocode Building Code on theese issues (available in Eng!). They are mostly created by German universities and Institutes, so they are pretty sound. For example interior insulation is something, everybody try’s to avoid for good reasons. U have literally no active Thermal mass and u will always have a dependency on artificial ventilation/dehydration methods, since there will always be a humidity problem as well. Also nobody is using oil based Foaminsulations in the interiors, for health reasons (except for slabs without possible connection to the air). IF u realy need to have a interior insulation, you always go here for a mineral based insulation like foamglass, which can be plastered with lime-cement plaster (natural desinfection of the wallsurface) and is beeing able to „breath“ humidity in‘n‘out to a certain degree. But if u build new, always try to avoid this stuff by using perimeter insulation on the outside of the basement, incl. a drainage plate and geotextile against the refill.

[@AnthonySmith]

I've never built anything more complicated than a dresser, no idea why I watch this but I enjoy it so much!

[@briancnc]

Steve seems to be a humble and very knowledgeable architect, thanks for sharing!

[@LongLiveOurBuildings]

Extremely lol!!!

[@studioGEEZ]

Matt, love the videos. Q: Is there a separate radon barrier that turns down at footing in addition to that 10 mil turning up the wall? Or does the CCF keep the gasses from infiltrating the basement?

[@nononsenseBennett]

What about off-gassing? Long term air quality studies?

[@Mrbfgray]

I suspect that's in God's hands. ;-)

[@chrishuyler3580]

Many homes in New England have issues with radon. It's easily solved with a mitigation system that could have been installed in the basement and home walls before this project was wrapped up. it's basically just a vent tube with an air pump.

[@nononsenseBennett]

@@chrishuyler3580 Thanks. Good info

[@alanbarnhill930]

From up north, too bad more builders don't insulate properly. Why not insulate on the outside of the basement concrete walls? Provides a thermal block and keeps the basement and main level floors way warmer...

[@rasi9845]

Also, imagine all the extra SPACE you get to have! [1:30 > super space hog]

[@chad6504]

That’s where my 2” rigid insulation is on my basement!

[@nb-eq6rw]

I assume it is. Under the slab is insulated, so why wouldn't the walls be? This is just a mega house

[@drxpfn9009]

What do you insulate the outside basement walls with?

[@mrmadame28]

Yeah its the vest way, but cost more. People just see the price tag unfortunately

[@bryandjen107]

Matt you jsut get it man. Love your info and tutorials. Im a DYI'er and your info helps tremendously. .

[@Patrick_Cashman]

I'm confused about the closed cell on the basement walls. In the floor you have EPS then poly then the slab. Why not have EPS and poly on the outside of the walls to decouple the foundation walls from the earth outside, insulate the walls, and keep the moisture barrier on the outside of the walls instead of the inside. Aside from the thermal issues, it seems that hydraulic pressure from moisture coming through the foundation walls is eventually going to push the closed cell away from the walls, and pool water between the walls and the foam. Looks like the right idea in the floor, but backwards in the walls.

[@flexiblebirdchannel]

Patrick It's a terrible construction, but the US can't build concrete housings. Look how it's done in Germany, they know how to build massive. Never use sprayed PU foam on the inside. It contains harmful substances. Keep the concrete on the inside, it will hold the temperature and moisture constant for good room climate.

[@mojomaze]

I agree you have to keep the moisture out. With that design the concrete walls will be constantly damp.

[@paulnovak833]

My guess is the outside foundation walls were also waterproofed. The issue with eps on outside is in cool climates the earth expands and contracts and eventually will destroy the foam. This is why it is now required in many areas to have a 6 mil Poly between earth and eps to act as a slip but this never works in reality. The technique they are using is a very good and cost effective solution if building this way. I only build with icf which solves all these issues with ease

[@jamesbloom1439]

@@paulnovak833 How is the foam exterior of an ICF block any more resistant to those foam-destroying forces than sheetfoam or sprayfoam applied to a block or form-poured basement wall?

[@paulnovak833]

@James Bloom icf block isn't going to move, nor would spray foam fornthat matter

[@johnbecich9540]

Awesome educational material, here given by two guys who are "national treasures" in my opinion. So no disrespect intended by my following comments. I am deeply grateful for EVERYTHING you do, and publish, so the rest of us can WATCH and LEARN. Especially, thank you for the warning of the "iceberg" moment that will wreak havoc if layering of building materials is mindlessly wrong! Meanwhile: 1) There is no mention of how deeply placed, below grade, this basement lies. 2) There is no quantification of the hydrostatic pressure exerted upon anything. 3) Is this on hilly, or flat, terrain? I've seen another of Steve+Matt videos, shot in Texas, where the surrounding land was shown, while a huge ground-water remediation project was poured. Egad that was awesome and mindboggling, to see that such countermeasures even exist. So many people (here in SoCal) just ignore geological issues. Not to mention all the SF-Bay people who live atop a powder keg... the San Andreas Fault. 4) I love the 10 inches of gravel, and the mention of French drains etc., in other words, this is a comprehensive solution; but: 5) If that gravel ever gets silted up, by any means over the next century or two, then really nasty things are gonna happen; so 6) Anyone who believes in, or uses, dry-well-type methods of sub-foundation water removal must contemplate the importance of all those air gaps between the gravel pieces. The gravel might hold up the building, but it's those air gaps that fill with water and allow an underground river to flow. Thank you for considering my comments.

[@randomrazr]

sot he house if fucked?

[@MaverickandStuff]

From what i have seen and heard it is best to not have the foam directly to the concrete. They make a special drain mat you are supposed to attach to the wall behind the foam to allow the concrete to breath. The same style drain mat is attached to the outside of the foundation to direct moisture to the drain tile at the footings.

[@paulsp6371]

That "interior weeping tile" solution is designed for basement walls that still have some water leakage from outside. In such situations it is better to permanently fix the water infiltration problem on the outside of the wall. When you can't dig up the outside on a cost effective basis, e.g. due to a shared driveway with a nearby neighbor, then the interior weeping system can be used with a connection to a sump pump pit.

[@gaylehiner9511]

@@paulsp6371 I have done a lot of remodeling on houses that have open cell and closed-cell they have been holding water and rotting box plates sill plates top plates and is a climate for post beetles and termites what's on paper is one thing what's going on in the field is completely 100% true Owens Corning opening letterhead stated they will not get involved with spray Foams because they feel that it's the next asbestos material and we don't have enough technology to understand it at this point

[@1goblingreen404]

@@gaylehiner9511 I could not find that letter. Do you have a link? I have seen another video where the foam needed to be removed/replaced due to poor application and serious air quality issues. Risky when you see some of the people that are installing this stuff. Not all are quality people.

[@kevinmccune682]

@@gaylehiner9511 The next "asbestos" is already here it is called "fiberglass"

[@rsmith02]

Owens Corning makes foamboard...

[@metror3]

keep in mind, a closed cell insulation, below grade, on an exterior wall is illegal in the Midwest which is why it is also illegal to use a vapor barrier or in some cases, not even faced insulation under those circumstances. The moisture needs to be able to evaporate vs. being trapped.

[@Shad0wC0mpany2]

Rob Fischer I noticed that they mentioned NOTHING about moisture barriers in this video...

[@MW-gh1mo]

Yep, that wall has 2 sides, and there is no way to guarantee that they can keep moisture out of the concrete wall, thus it has to be able to dry to the inside.

[@Mfgguy]

I wondered about this...check some of the articles Building Science Corp and Fine Homebuilding about why this works. According to Joe Lstibirek, PhD, 3.5” of closed cell still has enough vapor transmission to allow it to dry to the inside. Anything over that could be an issue.

[@stevenbaczekarchitect9431]

Why is moisture in a concrete wall a bad thing? do you think it is going to rot?

[@stevenbaczekarchitect9431]

@@Shad0wC0mpany2 That's because I believe in airtightness, water management, and surface temps of condensing surfaces - with that vapor doesn't scare me at all

[@christopherbranscum7402]

Why not just use ICF for your Foundation Walls? Thermal Breaks/ Wall studs all in one.

[@timberwolf9363]

Christopher, my thoughts exactly.. In the white north I don't know why would anyone build basement out of anything else but ICF... beats me.. O hold a second, I think I know.. TIME.. :) :) Everyone is builder these days and quality doesn't matter anymore.. Just this past January I saw a builder doing following: Day 1. - temp outside = -25 deg. C - dig a hole for basement Day 2. - 4 - temp outside= -25 deg. C - forming company doing forms Day 5 - temp outside = -25 deg. C - cistern and pump on site pumping concrete Day 6 - temp outside = -25 deg. C - forms are off by the way, no heating whatsoever was done... Now that concrete doesn't have even 10% of bearing capacity and then people are surprised that basements crack. That concrete froze the minute it hit those cold forms. I'm in the process of building my own house and it's ICF all the way to the roof. I'm not saying that everyone has to do that but for sake of insulation/thermal breaks, stable foundation etc. etc. use ICF... Building in Ontario these days is a big joke and consumers have no idea, they just keep buying..

[@DanielRichards644]

cost is the biggest factor, cheaper and easier to just spray the wall later. also tighter this way since the spray foam wraps into the floor band

That's what I did, (use ICFs) 18 years ago. I also used form-a-drain to pour the footings, and french drained the footings, inside and out. In western Washington we have very little radon, but that would also drain away any radon, as radon is 7x as heavy as air. The idea of insulating the slab is, at best, controversial, as the slab is a heat sink. If the heat can't escape sideways, it will just come back up into your house. My foundation walls are 4' deep, as I am in a wet location. With insulation 4' foundation walls, sideways movement of heat very unlikely.

[@davetaylor8614]

BenjaminFranklin99 You built a good system, best is to insulate below slab because heat always goes to cold, i.e.. interior temps 68 f and grade 4' down 60-58f thus constant drain of heat to grade. The biggest factor is wet soils providing better conductivity to concrete and greater losses.

[@markjohnson6498]

@ Yes that is the exact same system i use as well. The difference between regular forms and ICF and form a drain is that ICF can be done by anybody. In my personal home I had such a hard time with local ordinances that i just raised a 2x4 wall all the way around my basement. My spray foam guy went ahead and foamed it with rest of house so my basement is super insulated. I would never do it any other way.

[@spaken2768]

I didn't insulate my basement until I watched this

[@blazeharding574]

Keep these northern climate videos coming! I love what you do, but I have been dying for some videos that pertain to the "other half" of the country. I think you will really expand your audience.

[@DeepakBhat]

we cant use thos eps in India because of mouse :(

[@justanotherguy9664]

1:30 - holy cow.... what is the costing for this room; and, is it ever going to be "worth" the money put into it...?

[@williammitchell8247]

When its new construction it is less expensive to do these projects. Also, when your electricity bill for a 2000sqft house in New England is less than $200 in the winter it will be well worth it.

[@suijinnoname6412]

How much is it worth to have the room downstairs in your basement not cold if you actually want use it. I know from experience it is a real drag to have it cold. I did the math with some quotes and it would never "pay" to insulate the room from savings but it would make the room pleasurable to use versus having it virtually unusable. Of course in the summer that room is the best in the house, always nice and cool.

[@USNERDOC]

Excellent! Love to see these details and hear the the discussion of why and how it integrates into the system. 👍

[@paperwait9611]

i would suggest that you watch the whole video. baczek discussed the details and how it integrates into the building envelope system in the video.

[@USNERDOC]

I did watch the whole video

[@online_screen_name]

Getting some tricks for your property additions?

[@buildshow]

Thanks David! Hope you are well sir. Enjoy your IG feed and KZbin channel! Your travels are my daydreams of retirement someday. Best, Matt

[@USNERDOC]

Absolutely!

[@boedillard8807]

Any exterior foundation wall installation?

[@kmattar]

Concrete plus framing then closed cell = additional labor of framing, high cost and huge loss of real estate! ICF wins in all 3. Then the issue of close cell environmental impact and fumes.

[@daversj]

You dont get an air seal or the continuous thermal break completely up to the top of the rim board with ICF. ICF is very good but this is better at a higher cost. This architect does very high end work so budgets aren’t the main consideration.

[@AdeptHomeInspections]

How do you know where the moisture is condensing in between the closed-cell foam and the foundation wall? Seems like trapping moisture in there might cause degradation of the foundation wall over time.

[@Eger7law011]

Always seal the outside of your concrete walls from water penetrating down to drainage system and sleve drainage piping from sediment buildup.

[@myscorpions]

@@Eger7law011 Doesn't answer the question

[@zyxwvutsrqponmlkh]

The bugs will eat that Styrofoam, it won't age well.

[@silentcaos]

good vid Matt, glad this wasn't another infomercial....stay real , stay unique ..

[@joshuasmith1215]

Was the exterior basement wall insulated? That seems to me like the place to start.

[@loktom4068]

How many people bulldozer their house after this video ????😵😭😤

[@machone7580]

I insulated my basement floor with 1" of XPS foam, 5/8" OSB on top secured with concrete screws. Works well and much, much cheaper than those insulated basement floor tiles. Losing an inch and 5/8 headroom is not that big of a deal.

[@davec.3198]

Yup..and XPS is a nice vapor barrier!

[@BornInTheCreek]

Steve looks like an old time retired WWF wrestler.

[@stevenbaczekarchitect9431]

@the shop OOH RAH!!!

[@stevenbaczekarchitect9431]

I have done some wrestling in my time - just not professional

[@geofffelsing1283]

Why is there a gap between the gravel and foam?

[@dshepherd6085]

From what I could gather was to make sure moisture never came in contact. That gap provides an escape for any water through the gravel before it can reach the foam or slab. Not an expert and only speculating.

[@landonlandon5533]

So the entire 4” slab is floating in the air lol?

[@dshepherd6085]

@@landonlandon5533 So, you also don't know.

[@Prorex1911]

Hey Matt, can you address any questions or issues people may have with their insulated slab cracking? Apparently many people doing this are having problems with their slab cracking all over. Any info would be great. Thanks.

[@jaba512]

The concrete cures too fast from the surface and shrinks faster than on the bottom. The plastic underneath the slab slows down the curing, since the water can evaporate only upwards from the concrete. Cover the surface with a tarp to slow down the curing.

[@jamesharder5643]

The most common concern I had when I was in redi-mix was concrete being placed too wet. Contractors were known to ask for more water added on the job. While it makes it easier to work in the moment, the loss of cured strength and shrinkage cracks are high prices to pay. The above comment about the poly seal below requiring all of the moisture to migrate upwards bears true. Keeping the surface of concrete damp as it cures is never a bad idea.

[@Mad.Man.Marine]

@@jamesharder5643 so it would prob be prudent to wet cure a slab that is poured over foam and plastic?

[@eugenementz3195]

Tell me about the cross section of 2x material under the floor joists above. Where I live, most contractors insulate between the floor joists and drywall directly to the floor joists above (uusing blocking to stabilize the floor joists.). What is the benefit of the 2x lumber attached and running perpendicular to the floor joists I see in most of your videos? I live in NE Pennsylvania.

[@jguyis]

Now I'm going to ask a layman's question. You have compacted dirt, then the rock bed, the under slab insulation and then the vapor barrier. The video clearly shows that none of that is compacted. How do you pour a basement foundation that does not compress the under slab insulation and keep an air gap?

[@Eger7law011]

Foam board insulation under a bering wall will not compress more than 10%, under 4" of concrete floor not at all.

[@leoads]

Closed cell foam in a basement? If there is a leakage how it’s gonna dry? Elaborate please...

[@Eger7law011]

Closed cell foam is impermeable to water, um unless there is a earthquake that might fracture or tear it apart just not likely up here in New England.

[@Cotronixco]

In northern climates, insulate the basement slab in a first home, and do NOT insulate the basement slab in a home that is not occupied consistently such as a second home.

[@stevenbaczekarchitect9431]

I use the rule of insulate anywhere I buy energy

[@Cotronixco]

@@stevenbaczekarchitect9431 It would cost more to heat a second home if the basement slab were insulated in northern climates such as here in Minnesota.

[@jonpaton4449]

New build? Why not insulate the outside of the wall?

[@stevenbaczekarchitect9431]

Don't agree with that practice

[@jonpaton4449]

@@stevenbaczekarchitect9431 What do your engineer buddies say?

[@KenPaulsenArchitect]

Our code requires the "EDGE of slab" to be insulated. This video doesn't seem to address that area.

[@randomvideosn0where]

He said they turned the insulation under the slab up at the walls 18"

[@danquestnorth768]

@@randomvideosn0where That was the vapor barrier and that would be on the inside of the basement. I would bet they insulated the exterior of the the slab as well.

[@juliem632]

Curious if you wanted a cold cellar in the basement would you do this or would you not do the section of the cold cellar?

[@10tenman10]

I think it is more important to have insulation on the outside of basement walls and underneath the basement than on the inside.

[@justinianoamado276]

Agree 100%.

[@stevenbaczekarchitect9431]

Been doing it for 30 years - and totally don't agree

[@andyh8239]

Doing this in a northern climate: Wouldn't this increase the risk of cracking the wall? Block ground heat, thus freezing, and swelling from ground water.

[@firemanj35]

Generally below 4 feet the ground stays pretty close to the 55 degrees Steve mentioned. So there is no risk of water freezing. Now that should be true throughout the US except for Alaska. I have no idea about Canada. So ask Mike Homes about up there.

[@andyh8239]

@@firemanj35 Thats fine for the portion of the basement 4 feet below grade, but your going to have that 4 feet freezing. Better have really good drainage.

[@ArneJohanssonMpls]

Steve doesn't like the Outro? Come on that is the best part! I am getting ready to install insulation before my slab goes down. Doing that same technique.

[@khaleefax9553]

*NEVER EVER EVER EVER use foam insulation in your basement ESPECIALLY in the floor joists. You are talking about a NIGHTMARE with mold and humidity issues.* *I removed padded insulation and got the sprayed foam insulation, and DESTROYED my basement. There are many videos on that on youtube.*

[@MovadoDaSaint]

Steve at the end made this my favorite episode!!!

[@stevenbaczekarchitect9431]

Thank you!!!

[@larrymaloney877]

You are wrong, Steve! The closed-cell foam DOES NOT "warm" the surface of the concrete. It does stop heat flow. In winter the foundation wall will be colder, not warmer. And I don't know which is worse, the damage done by foam to our environment or to the buyer's wallet.

[@BjorckBengt]

Sure it would be better to have the foam on the outside of the walls but since that is not an option this would be the next best thing to do. There shouldn't be any problem with a concrete wall at surrounding temperature and moisture levels. Foam under the slab is a fantastic design and the most common foundation around here combined with water based floor heating, though we use 300mm thick foam layers.

[@larrymaloney877]

@@BjorckBengt , agreed, foam sheets under the concrete floor is a suitable thermal barrier. But what thickness?

[@BjorckBengt]

@@larrymaloney877 It all depends on your heating cost. In Sweden the standard was 100mm for a garage at 10C and 200 for living space. Now it is 200mm for a garage and 300mm for living space. Anything above 100mm is good, above 200mm is great!

[@BjorckBengt]

s.skbv.se/static/images/uterum-grunder-grundpaket-78359/503800

[@larrymaloney877]

@@BjorckBengt, is there a point or purpose to your photo link?

[@Arminas666]

Loosing heat through slab, LOL . Do you know earth temperature is 61 F ? Assume you 8' below grade how much heat you loosing? Assume you know warm air is rising , cold falling? Maybe you want insulate slab because you don't want moisture?

[@erickessler6094]

Matt, Steve, Brilliant video. Sorry but I'm still the dummy... Let me make sure I understand this correctly... 👍 the "green-line" as you called it, is the continuous foam insulation boundry which is a "foam - touching - foam - touching - foam..." from basement floor to foundation wall, to band joist and sill plate foam to house walls up to roof? A big igloo cooler. Ok ... Now does this mean ... the below basement slab "floats on & between" the closed-cell Type-9 EPS foam under the slab and between the foam basement 2"+ sprayfoam touching lower basement wall foam??? So foam touches foam...? Or do we actually have a slight breach where the basement concrete slab is poured atop the type-9 foam... and THEN the 2" basement wall is spray foamed, meaning the wall spray foam really sits atop of the concrete perimeter and really doesn't touch the 2 layers of the Type-9 foam boards below the slab? Thanks so much men! Eric

[@Mfgguy]

This was great, good to see more about cold climates and more about basements.

[@metro484444]

The poly is also required for radon underslab control. Mass Code requires piping installed under slab

[@Had22s]

If doing new construction why not ICF?

[@neckofthewoods24]

I am. Screw all the extra work in insulation. Run the floor foam on top Stone and on top of the footers budding up next to the ICF foam walls then pour the slab. Now it’s all thermo broken.

[@GoPappy419]

Matt, Can you comment on the concerns on off gassing of closed cell foam and is there anything that can be done to reduce this concern

[@wojciechpestkowski8714]

I don't agree with this at all. You are causing the EPS styro to get wet by this and hence it is non-vapour blocking material it will be wet on and off and finally degrade, which in this scenario will make it useless for thermal insulation. You should have used XPS. Or, better is to put polyethylane foil on a first slab, kinda thin (10 cm, 4 inch) - thats what we do, we dont put rocks. Beneath that first thin slab is SAND. Then on the thin slab you put the polyfoil, on top the hard EPS, and finally the concrete slab - the finishing one. Therefore, it there is moisture on top it will go right do the foil and evaporte, and from bottom i will not go though the foil to the eps I have also posted a message about your R values, because i was amazed of R value i.e. 60 until i figoured it out - it is for a square inch. So to be short, we use insualtion of >100 R value in your terms in here, Europe, Poland.

[@hybridamerica]

Now, a few years ago a contractor friend of mine was telling me a horror story about a family that had foam insulation sprayed in their attic - very similar to this - the family kept getting sick and it was determined that the outgassing of the foam was making them sick. Do any new products address this issue?

[@imzjustplayin]

The outgassing is only an issue if the chemicals aren't mixed properly.

[@stonebody]

Matt I see vapor barrier down first then insulation board then a pour in a lot of videos coming out of NE area. Steve shows it opposite. I am in the mist of a frost wall slab build with 2” EXP R 10 board up the walls and then capping with 2” EXP so placing the vapor barrier is crucial What is the correct science Thanks D Stone

[@alchemistTi]

How much heat really works it’s way down through the slab? Heat rises, so it can’t be THAT much, right? And in the winter, 55* earth temps are warmer than the outside air and actually help warm your house, right? That’s the whole point of geothermal. I’m not trying to be a cynic - I genuinely don’t understand the logic here.

[@flinch622]

"Green line..."? Wrong thinking - leave that mush for mba's, who know little to nothing about most matters. How about... does it work? A home is a box controlling air, moisture and temperature factors. And as common sense dictates, if you tried shipping something in a box with a side missing... it's not going to go well.

[@joemommma6573]

steve knows his shit. thanks Matt

[@drummerboy6178]

Here I mostly see 4 inches of gravel (stone), 2 inches of foundation plus styrofoam, heavy duty poly, then 4 x 4 sheets of wire mesh then 4 to 5 inches of concrete...

[@KunjanChauhan]

never understood why Americans and Canadians are so keen on using foam inside buildings. It's sourced from an oil industry byproduct and off gases gases for years after and this would be in an air-tight dwelling...! One can use rockwool (without formaldehyde binders) or wood based insulation...!

[@bksduskmirror1250]

Never insulate right down to the footing in freezing climate, the foundation will freeze and crack. We get 4 to 5 feet of frost up here, when it freeze everything breaks

[@AndrewSpencer2]

Wait a minute, isn’t the membrane supposed to go UNDER the EPS? Also, it doesn’t look like the 15mil stegowrap you’ve used previously?

[@TheShomare]

This video was lame. Didn't state much of anything in regards to insulation of the slab. Builder info only for builders I guess, who don't know what they are doing?

[@johnwhite2576]

I'm not sure I get this. The vapor drive for the most part will be through wall from soil outside which is mostly 100 relatively saturated even in cold months. without exterior insulation the dew point will be isnbdie the house albeit inside the foam.why isn't this a problem ??

[@johnmiranda2307]

Hy-Tech aluminized paint for concrete along with radiant barrier under the slab keeps my “unheated” basement 6degrees warmer in winter than the main floor, which has radiant heating. My basement is a rectangular pizza box

[@am4230]

I'm convinced a thermal break can be obtained with less than the thickness of a double walled coffee cup; with very little R-value and at a fraction of the cost of these systems. Anyone think I can't?

[@johnwolf1475]

Is this because concrete don't breathe? No geothermal sink working for the home? So u r building a thermos vs a living breathing shelter that works naturally

[@1961fireguy]

Biggest mistake I made in my new house was not insulating under the slab! The tile floors in the bathrooms are uncomfortable in the winter due to cold radiating through the slab. Floor temps get down in the low 60's which makes the heat have to run more often. Great video!

[@stevenbaczekarchitect9431]

Thank you sir, I agree, if only the knuckleheads above would listen to reason...

[@rusosure7]

@@stevenbaczekarchitect9431 LOL! I'm into Monolithic Domes and there the concrete is exposed on the inside. Why? Because of 3" of polyurethane insulation on the outside. It's like eating a Goose Down jacket to keep you warm... No, you put the insulation on the OUTSIDE.

[@HotNoob]

dig out the perimeter of the slab, and slap some EPS boards around it. it'll do a good enough job, because soil is insulative and a thermal mass. you have infinite insulation on the bottom; it all escapes SIDE WAYS. the further down you run the eps boards, the more insulative it will be. varies a bit of course. say your soil is sand; sand has a r value of 7 per foot. run the EPS 4 feet in the ground, and the heat will have to go through R28 on the way down, and then another R28 on the way up to leak out to the surface.

[@SunnyhillHousingCooperative]

Man, you are just selling your products and services -- Can you be more objective? Heat goes up, not down.

[@sunshinecompany1]

So put rigid insulation on rock...then Polly? I was told to put plastic first?...so confused 😲

[@ParmMohan-us6rn]

I can't imagine concrete getting underneath the foam and making it bouyant? Who's the placer?

[@LongLiveOurBuildings]

I've seen it, its not common, I'd just rather not take the chance

[@ParmMohan-us6rn]

Steven Baczek wow, that's all I got to say. Wow!

[@994pt4]

agreed...foam should never "float" to the top of concrete unless they pour soup for concrete!

[@zpetar]

EPS is not good option if there is water or moisture expected. It can absorb water and when that happens R value will drop. XPS is better option

[@ndchick1]

Great video!! I have designed basement slab insulation systems and never stopped to consider WHY we put the poly on top of the EPS. Makes total sense! Just say no to "iceberging"!

[@rotaxrider]

So poly on top of insulation and not underneath? Is this how code wants it?

[@scottward2366]

@@rotaxrider in my area (central canada) I have never seen a code showing specific order... I typically do poly on top for this exact reason... Building inspectors never question it.. they just want to see proof of foam thickness if the plans called for a specific thickness..

[@tedfritsch3340]

This concept is awesome, making that basement air tight. Out west here in Colorado and SD we have issues with Radon Gas, I would think this would negate the need for a radon gas removal system saving a ton of bucks.

[@kirill_gusev]

Radon (and radon mitigation systems) is pretty common in Boston area. I'm sure the building the foundation this way is more expensive than radon mitigation. And radon seeping through the concrete so it would need to be installed anyway.

[@webmoore4353]

Unless you insulated the exterior wall you will have issues below grade with vapor and moisture. It will trap it coming from outside

[@lorenmorrison3402]

i always see people concerned about a heat sink or heat loss, but from experience with growing up in a basement house that was an uninsulated slab, that is the only place you wanted to be in the summer. the basement was always cool, eventho it was almost a walk-out basement, with full windows on 3 sides. so for all of the people that experience more heat than cold, why not let the ground work for you?

[@leeroyexcavator9149]

All that under the basement floor is way overkill in my book. Extra exspense for little gain. I have a poured basement not a issue to heat or cool. That foam in my area would completely destroyed by ants at least they love the blue foam sheets.

[@Frankengruvin]

The slab looks like it's floating. It appears as if there is a small (one or two inch) gap between the gravel and the foam layer, with the concrete poured right on top of the foam. How is this? Or is it that the is foam resting right on top of the gravel and the gravel has been moved away slightly from underneath the foam in the cutout you used to show the layers? I can't figure out why it appears this way, and if there is any significance at all.

[@mrmadame28]

You can have problem with close cell urethane when the exterior of the foundation is not protect from humidity with a membrane. The foundation can become brittle tonthe point where you can get a screw driver in the concrete... I believe this have something to do with bellow zero temperature

[@jensmllgaardjensen4150]

It’s fun to see how you Americans build. I my country we never use spray fome insulation, we have to use Aerated Concrete as a minimum for basementwalls do to floodrisk (no wood or plaster), due to dampness we always insulate on the outside of basementwalls, because insulation on the inside Wall without ventilation will not be a good solution here. And then there is insulation thickness. We use 4-5 times the insulation that you do. A slab like this can easy take 400-500 mm EPS

[@seigeengine]

The basement walls here are concrete? Yes, you could put more foam under it, but why would you? Boston has about the same ground temperature as Denmark, but the ground is one of the least sources of heat loss in a home, which means putting 400-500 mm of foam under the slab doesn't make sense unless there's at least equivalent of 400-500 mm foam in your walls and ceilings as well (preferably more), never mind windows/doors/etc.

[@jensmllgaardjensen4150]

Well I see many interior basement walls in this videos that are woodstuds and plywood or sheetrock. We can't use that anymore here, the insurance Companys here will not cover anything i a floodet basement, if its made of wood. Aerated Concrete will get wet but it will not rot or grow mold. You can just dry it out. Studs, Ply and Sheetrock will rot and grow mold fast. In Denmark the buildingcode says that a house must at its max use 36,7 kWh/m²/år. in heating pr. year for the lowest grade of energi efficiency. They make this tighter every cople af year to make building more energy efficient. We have to make a calculations of the energy needed to heat the house, to get a building permit. You don't nesseceraly have to have the same thickness of insulation everywere to have high energy efficiency. In the cold you can come a long way if you have warm feet and a warm head. In Denmark the slab and the roof are considered a relatively larger contributor til maintaining the heat. In a one story home, the slab takes op alot of the building envelope. If we have many large windows, with relativ to the wall, low insulation value, we need to put more insulation in other places.

[@seigeengine]

Oh yeah. We just don't tend to build basements in areas prone to flooding.

[@jensmllgaardjensen4150]

seigeengine we don’t eather unless they are flod safe. But in Citys a large part of the building mass is from before 1900, back then basements was normal.

[@jensmllgaardjensen4150]

seigeengine but you probobly have a wather main in your basement or other installations that can leak. That can make for the same result as a flood.

[@janrozema7650]

Nice Smerk at the end. For a euro Guy those very American slogans feal so forced....

[@inaf1079]

Richmond American Homes in Colorado, do NOT insulate a basement like that. Makes me sad and jealous.

[@barrysumrall7627]

In older New England houses with a rubble or stone foundation rather than poured concrete, spraying foam isn’t recommended. Is there another solution?

[@xternalpunk]

I have an older home with cinder block walls that have seepage. I don't think this would be advised for someone in my situation. I had to break concrete and run internal drain tile and drill weep holes at the bottom of the block.

[@konjiki240sx]

Cinder on grade or below?

[@xternalpunk]

@@konjiki240sx below grade.

[@NightSky777]

Wow, that's some nice Detail! ...but curious about the foam Between the concrete layer? 2" slab, foam, 2" additional slab?

[@jeffreyquinn3820]

Just a few comments from living north of 50 degrees latitude: (I'm not really an expert, so please feel free to disagree.) Bat insulation doesn't perform as well in basements as above ground, because the difference in temperature at the top and bottom of the foundation causes vertical air movement within the bat. In the dozen or so basements I've torn up, there are always some spots that have been continuously wet, even with proper vapour barrier & moisture seals, drainage, etc. Any kind of hollow wall construction in an exterior basement wall in a bathroom will cause problems. I prefer to attach foam board insulation directly to the foundation wall and drywall to the foam for these. I've only seen sub-slab insulation when there is in-floor heating, with the exception of one house about five hours north of Toronto that had full-height south windows that heated the slab in the winter.

[@xNoLimits84x]

No termination bars? Why do you use a 10 mil vapro barrier instead of using an actual waterproof membrane? Also making sure that the joints of the EPS are staggered is a key point in maintaining the R-value when using multi layered rigid insulation.

[@cynthiaarmstrong7972]

I’m assuming rebar was laid on top of the plastic before concrete was poured…

[@GM-kt5uf]

How do you insulate the slab when you are using Superior Wall prefab basement walls?

[@mcmarmot137]

Can a concrete slab also be poured on extruded polystyrene?

[@curtisbme]

Are the walls not insulated on the outside? If they are, is the inside insulation needed or is it just giving you 'extra'? Wish my slab was done like this (or done in any competent way..). For our daylight basemetn foundation walls i used Insofast panels as we weren't going to spray foam and didn't want to use the space to foam panels and stud wall.

[@bradkvanbek7148]

Eliminate the wood framing with InSoFast, or better yet ICFs.

[@tableshaper4076]

What happens in 20 years when all that insulation starts to degrade? Your slab will soon be floating with a massive air gap.