Will rigid foam cause problems? My foam board after 3 years! | R-30 with 2x6 rafters update

We send an endoscope up behind the insulation to look for possible damage. Surprising results!
Here's the original video on how we got R-30 with 2x6 rafters: • Getting R-30 in an att...
Bi-fold bathroom door: • How to cut/trim and in...
Foamboard links:
www.gaf.com/en-us/roofing-pro...
www.menards.com/main/building...
0:00 Intro
0:56 PPE
1:30 Crawling behind the knee wall
3:02 Starting the endoscope
12:51 Conclusions
13:56 Extras
#R30foamboard
#fiberfaced
**Disclaimer:
If you choose to imitate, duplicate or copy anything you may have observed in these videos, you do so at your own risk. The creator of this content does not take any responsibility for any action taken as a result of the information or advice on this KZbin channel (or other platforms) and shall not have any liability in respect of any injury or damage that may result.

[@five-eyes666]

I watched your original video's and started my attic/loft shortly after. Great to see the air space is clean, and encouraging for me with my insulation project. Thanks

[@FamilyFriendlyDIY]

Thanks for the kind comment!

[@Mark_Nadams]

Thanks for the videos. This insulation method is exactly what I been wanting to do for our old house. Our house is old enough that the wood is all rough cut actual dimension wood. So I will be leaving a full 2" space to the roof and then I will come out even with the rafters for the last layer. Not to worry about the light you were seeing at 5:50, It looks like it is a reflection of your camera lights off more spray foam that came through. The humidity problems in the Summer are common in older homes. for all the reasons you mentioned. The problem shows itself whenever you have a transition zone and may actually start in your cellar. I would also double check that the PTACs properly separate inside/outside air flows and are plumbed indoors for A/C condensate drainage or have a removable drainage catch. The drainage path should be checked and cleaned seasonally.

[@jr.8509]

I'd call it success.... it's a good game plan for what I want to do... appreciate you sharing

[@VmanJeff]

Thank you for this! We have pretty much the same construction (1957 build with a late 60’s addition). Finished loft but unknown insulation in roof/ceiling but that room and the kitchen/garage beneath get pretty hot in summer. My lady uses that room as her studio and I really want to make it comfortable for her! My only idea is I’ll need to remove some ceiling drywall to check the construction and insulation then follow a similar path as you if necessary. I have to laugh as you crawled back there. I’m 62 and make those noises all the time. It will be such joy crawling into all my spaces 😅

[@timbohall2799]

Thanks for showing us your wood.

[@damienrios9267]

I enjoyed watching your videos documenting your progress on your home renovations, any other plans for the future?

[@FamilyFriendlyDIY]

Thanks, Damien! My favorites to film are the renovations, and yes, lots of plans --the list is endless. I'm backlogged by probably 15 or 20 videos right now that I've recorded but haven't been able to edit yet. Most of the backlog is the garage conversion, but in my own home I hope to be raising some beams in the basement, installing a new underground electrical service, fixing a foundation problem and adding new columns to our carport, new front entry door, not to mention renovating the entire other side of the attic. Then I have a list of projects for other people I plan to film. I can't imagine I'll ever run out of projects!

[@aytviewer2421]

Thanks for the update Dave! And yes, I originally found this channel via that original 2x6 insulation video. One more note: You released a good lunch there at the end. No joke. We use to catch those snappers and after a little harvesting effort my grandmother would always fry up the legs and neck just like she would a chicken. Nothing like Kentucky fried snapper!

[@FamilyFriendlyDIY]

Ha ha. I think I’ll stick to chicken. 😉 thanks for the comment and your continued support Kelsey!

[@dtj9923]

I really appreciate you posting these videos. I have a 1913 bungalow that desperately needs second floor insulation. I got a quote on spray foam for just the second floor and it was $10K for my little bungalow, crazy! I'm looking to start by insulating in my walk out attic with rigid foam board and then move into the rest of the upstairs after I get the hang of things. Lots of plaster walls being ripped out for sure. My big concerns are ventilation and mold. Right now there is no soffit venting aside from the gaps in the T&G covering the area. The newish roof has a center ridge vent so that's a start at least. Not looking forward to this job but seeing your success is giving me hope.

[@FamilyFriendlyDIY]

Thanks! A lot of folks seemed to think I was exaggerating about the price of spray foam. Guess it depends on your location. All the best on your project!!

[@dtj9923]

@@FamilyFriendlyDIYI'm actually emptying my attic as I write this reply! With all of the crazy angles, hips, valleys and dormers in this roof I'm probably going to have to get some guidance on how to properly vent this situation. I'm not very confident I can insulate between the attic rafters and still get adequate air flow to the whole roof. My roof may not actually be a good candidate for foam board insulation. The advice I recieved previously was to pull up the attic floor and insulate under it then do the back side of the upstairs interior walls and then insulate above the upstairs ceilings when I put those back in. Love old houses!!! Always a journey.

[@khandam7709]

that glass door going to your attic area, probabaly has an Rvalue of 1. Add a sheet of insulation board over it to bring it up to R15 and seal it up better and your humidity issues should go down. this was a great improvement , good job!

[@FamilyFriendlyDIY]

Thanks Khan. And thanks for the tips!

[@un7ucky]

hot air rises and it holds more Moisture, so thats part of the issue, the unit also is common for having condensation issues when its on AC mode. i had one in my office and it was always damp on the plastic

[@maxwellsmart3156]

The room could probably use some sort of air exchange vent/fan since the houses humidity is accumulating in that space, especially as the room becomes more air tight.

[@sretniwe]

Just looking for ideas for my attic in 2022. $18/board in 2018 compared to $35-$40ish now. Ooof

[@FamilyFriendlyDIY]

Keep an eye out online for "factory seconds" Eric. I've had some people tell me they've purchased pallets of them really cheap.

[@geode232]

Hope you bought it at $40, @ that Menards link it's now $49. And foil faced at HD is $57 now

[@MCRideout]

Regarding the humidity problem- the ptac may be causing the issue. Try dialing the fan speed all the way down and monitor humidity levels.

[@FamilyFriendlyDIY]

Thanks for the suggestion. I'll have to look into that, but I don't think my fan speed is adjustable.

[@beardedgarage]

good original video and great follow-up. I've got a space I'd like to finish above my garage and I'm thinking about doing this, but my rafters are 2x10 so I could technically just go pink stuff and probably save a bunch of $. Any thoughts?

[@FamilyFriendlyDIY]

It would definitely fit, just depends on if you want/need an air gap. I think R-30 batts are 10" thick, right?

[@rickeverett3304]

And you can add rafter bay vent panels

[@dipling.pitzler7650]

It would be safer to add a vapor barrier on the " warm" side of the insulation otherwise condensation will form over time on the underside of the wood!

[@rivernet62]

I didn't notice if you talked about ventilating the insulation air space to the outside. I believe you need a certain number of square inches at the soffit and similarly at the ridge line so air can flow through and remove condensation.

[@BourneAccident]

I have a 20 year old house that we bought 13 years ago. I have had major attic problems. 1. Lack of insulation 2. Air infiltration from outside as well as from the interior space of my house 3. Ceiling penetrations that are unsealed 4. HVAC unit in attic 5. Hip roofs (3 sections) 6. Mice, rats, bees, wasps 7. Here's how I dealing with it. I am sealing all penetrations. I installed two attic fans. I am going to install 5 exterior passive vents. I just started installing 1/2" 4'x8' reflective foam board up to roof vents. Once all this is done, I am having blown in fiberglass insulation installed all over. Also, I moved my HVAC to basement and re-designed the duct work already. What a problem and tough for me at my age to get all this done quickly... but it will get done. The important thing is that I will have a very generous air space from soffit vents to roof and passive vents. So I agree with your comment and see it as very important. Thanks.

[@OidHunter]

👍 For having the balls to go up there and make a video 3 yrs after.. Have you used Thermawrap at all? I noticed the staples on the rafters in the video and wondered why they were there too.

[@FamilyFriendlyDIY]

I haven't used Thermawrap. There used to be kraft-faced fiberglass up there, so the staples are probably from that. Thanks for the comment!!

[@mjh5947]

I have mini splits and I have to run a dehumidifier otherwise it gets clammy. Maybe the PTAC is similar? Mine is the VRF kind so that's a big reason from what I understand so not sure if your PTAC is the same. Also I'm thinking the door has to be a huge source of humidity so I'd be curious to see what sealing off that door would do (experiment #2 video?).

[@FamilyFriendlyDIY]

Thanks for the comment MJ. Mine is not VRF, and you're right, the door might make a good experiment :-)

[@barabbasrift8874]

I'm going to do a cut and cobble but switch to unvented attic.

[@jban4457]

High humidity... my guess is the PTAC is oversized/too strong for the small space. If the unit cools down the room fairly quickly then there's your problem. You want longer run times in order to give the unit enough time to remove humidity. You can play with the settings to get the unit to run longer, yes you will spend more in electricity BUT you should recover that cost by not having to run the dehumidifier.

[@FamilyFriendlyDIY]

Thanks for the advice, John!

[@stevedyson1626]

Have you any before and after costs and savings? Thanks for doing this!

[@FamilyFriendlyDIY]

Good question, Steve, but I don't have a clear answer for you. Though this attic suite added around 500 square feet of conditioned space, our bills never changed. The problem is, the same month we began running the PTAC/heat pump in the attic, our house HVAC system (30 years old) went out and had to be replaced. So is our new HVAC system offsetting the cost of running the PTAC in the attic? Probably to an extent. But the new attic suite does seem to hold temperature very well, so the PTAC goes a long time between runs. I wish I had a better answer, but it was just how things worked out.

[@stevedyson1626]

Thanks for your note.

[@fahhad17]

hi dave did you anything with your corolla ! my one i drove already 11000km , not oil burn at all,

[@FamilyFriendlyDIY]

What???! Still no use? that's awesome Turbo! ... I've been wanting to get back to it, but some other stuff has gotten in the way. I'm editing an update video on the Corolla now. Hopefully soon!

[@LatinKingSosa]

How would you have dealt with bays that had no access to vents? I was going to do this exact install but then realized that not all the bays went down to the soffit. I think my only option is to sister the rafters and either do all spray foam or do spray foam and batts. The roof is a metal roof and not sure how ard it would be to add vents.

[@jm-lc3jp]

It's annoying isn't it. Let me guess? Cape Cod? options: 1) rooftop foam 2) smartvent (cut into first layer of shingles) 3) breathable fascia. Dont forget a ridge vent and use the spacers he used or baffles. If you have metal, then you might want 3

[@LatinKingSosa]

@@jm-lc3jp actually this is in Eastern Idaho, house built in 1920. I think I'm just going to do 2 inches of closed cell spray foam and then the rest with dense packed cellulose. I think down the road I'll redo the roof and add more insulation on the outside and waterproof it. I'll do some research on the breathable fascia. I didn't know what was an option.

[@jm-lc3jp]

I got a crazy expensive quote for open-cell foam, so I'm not going there. Some may caution you against closed-cell (because of not being able to see water damage to roof), not sure how true that is, but if you're worried about waterproofing just make sure the closed-cell isn't making the water pool and rotting your sheathing over time. Also be careful if you are putting the foam there without venting (I think Climate zone 5/6 probably needs venting unless you have a brand new 'hot roof' that you are absolutely certain wont have warm eves in the winter. 2 inches + cellulose is probably not enough esp around the hard-to-reach rafter tails that you may be setting yourself up for ice damning in the winter. You also can cut the closed cell flush to the rafters and put these same polyiso boards over them. But you would need to fill the entire full 6 inches with foam (if you want vented you'd use some of that 6 for baffles.) There's a This old House video that does exactly that. You may be luckier than me (ranchhouse style?). In cape cods you have have weird geometry that you cant easily get access to anything, so I was thinking about rooftop foam instead. No one wants to do it here, and I can kinda see why: weird geometry you add 6 inches to your roof (if you need to add ventilation and more sheathing), and so if you have dormers then your roofline is coming right up to windows and you have this extra long fascia--it's not a great option. If you have a nice simple roof then it should be easy to add two layers of rooftop foam plus ventilation. If you haven't already look into Hunter Panels (there are other manufactuers too, or skip prefab and can do the two layers in the Johns Manville install guide for polyiso. Then you make mock rafter tails to create eves and soffits. Check out Matt Reisinger's rooftop foam videos if you havent. Also Joseph Lstibuerk's 'To vent or not to vent' video shoudl be required watching by everyone I think esp if you're in a snowy climate. Good luck on your project.

[@misternordberg3675]

Thanks for including testing out the lapel mic, really relevant.

[@juliesnyder4627]

Is the foam insulation foil backed? Which side did you face to the roof?

[@FamilyFriendlyDIY]

This was fiber faced on both sides. No foil. It's actually commercial roofing insulation.

[@JohnDoe-pe6iu]

Given that a 2x8 is actually 7 1/4" deep and R15 insulation is 3.5", what are you thoughts on using 2 layers of R15 insulation in the 2x8 cathedral ceiling? Depth wide it adds up to 7" and also the R values add up to 30.

[@FamilyFriendlyDIY]

I think that's an interesting idea, but do they not make an R-30 that would fit in that space?

[@terryhoffman795]

if you do two layers of insulation make sure the inner does not have the kraft facing on it otherwise it can create a inner vapor barrier between the two insulation rolls. this will cause a reduction in thermal protection as well as causing a possible mold location to grow.

[@jeffa847]

I may be misunderstanding you but you need to have some ventilation between the roof deck and the insulation. It sounds like you are proposing to put 7" of insulation in a 7.25" bay. You can "encapsulate" an attic or a cathedral ceiling but there has to be additional consideration paid to really sealing everything up and making sure you have a plan for how the moisture can escape. Sometimes they put the insulation on top of the roof deck. It's really important to get it right or you'll end up with a rotted moldy roof

[@thehusband12]

How did you attach the dry way to the foam board?

[@FamilyFriendlyDIY]

kzbin.info/www/bejne/mnjIoHRnn86Sn68

[@user-fu5ex3dq1o]

How did you attach the drywall to the insulation?

[@FamilyFriendlyDIY]

kzbin.info/www/bejne/mnjIoHRnn86Sn68

[@bruceboock7553]

Why/when to use rafter insulation bs reflective paper?

[@drewtrailer681]

Maybe missed a video but did you drywall that foam you put up or just paint

[@FamilyFriendlyDIY]

Drywalled, Drew. Here ya go ... kzbin.info/www/bejne/mnjIoHRnn86Sn68

[@drewtrailer681]

@@FamilyFriendlyDIY thank you. Got to thinking I got a 1.5 story knee wall all that in Michigan. There is currently zero insulation up there. I got 2x6 I’m thinking about only going 4” r20 skip all that headache. Something is better than nothing and I don’t plan to sell anytime soon. What you think

[@FamilyFriendlyDIY]

@@drewtrailer681 Off the record, I think you should be able to do whatever you want. I personally think you’ll be happy with the results, but I do live in a much warmer climate. Please let us know how it goes if you do choose to do it!

[@drewtrailer681]

@@FamilyFriendlyDIY piece of an update. Started tearing in found out it did have insulation was loose bat. but on the slanted parts it gravitied down leaving empty spaces still going forward with foam board. The knee walls have insulation but im gonna go to soffits leave knee wall insulation. The loose bat on slants left no way for the roof to breathe. Kinda glad I tore into it. Still gonna stick with 2 panels thick r20 see how that goes. Have 24 panels in garage right now. Gonna get at it tomorrow

[@lfuentes4098]

Do you use a dehumidifier in the room?

[@FamilyFriendlyDIY]

Yes. For about 3 months in the summer.

[@bobbywanger8123]

🔥👍👍👍👍👍🔥🔥🔥🔥

[@Manlaw2012]

I don't see or hear you talk about a vapor barrier, but did you install one?

[@FamilyFriendlyDIY]

Nope. No vapor barrier, Jakob.

[@BobPritchard]

@@FamilyFriendlyDIY At that depth of foam, it is a vapor barrier.

[@Supercharged111]

This was my thought as well when I watched the install video. I'm surprised they made you meet code with insulation but let you run free on the vapor barrier. A space that's both heated and cooled is a little trickier than a space that's only heated.

[@tommavrakos]

Why put insulation in between rafters.why not use double stick tape and put it over it

[@FamilyFriendlyDIY]

I needed 3 layers. Putting 2 inside the bays saved headroom.

[@cabinman]

Probably so well insulated that the a/c isn’t running long enough to dehumidify. Today’s heat pumps are designed to run longer. You are probably short-cycling the unit.

[@TheGuruStud]

Rock wool all day

[@coltle8300]

The only time you truly need to wear a mask, not to the grocery store etc.

[@shopart1488]

What did you expect to find. If you put insulation there, it should still be there.

[@rickrolls3786]

No surprise at all this happened. It's supposed to be installed on the outside.

[@FamilyFriendlyDIY]

No surprise what happened?

[@jm-lc3jp]

Exactly: No surprise this worked out so well as it's a warrantied and supported installation method per John Manville "Attics and Cathedral/Vaulted ceilings" installation manual.