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Love how you gave the quick answer, and then gave the support… this respects the watcher and allows us to determine what we want or need to watch. Greasy job. And great job on the supporting video.

I retrofitted my 90 year old home with closed cell foam under the roof sheathing. There was effectively no air sealing or insulation there before. My natural gas usage dropped 50% in December in Ottawa. This video is making me even more confident.

We have open cell sprayed on the underside of the roof deck, It was done in 1998. The roofer did a poor job and many nails missed. These small leaks were not big enough to drip below, but big enough we noticed soft spots in the decking. Rather than take the roof off and deal with the soft decking we instead nailed 1x4" perlins through the shingles and put on a metal roof. There is now a one inch air gap between the original roof and the metal. Not only did this solve the leaks but the house is noticeably cooler in the summer. We are in Indiana so summers are very hot.

Leaks are tricky even at best if circumstances. Our house had a roof leak for years but we didn’t known because the cellulose absorbed it until it become a huge leak. Fiberglass loose fill 7:21 will let water through quickly. I’ve been using 12/12 and 10/12 pitches for years. We use closed cell foam on our new builds AND we use Huber Wood Zip roofing and Ice guard 4’ up and high quality underlayment. The chances of roof sheathing damage is very very low. Now, could damage occur one day if the future home owner don’t take time to visually inspect their shingles? Yep. But then concrete and steel eventually erode from neglect also. I’d the price of closed cell foam was 1/2 it’s current price, I would ALWAYS use it to make our attic spaces un-vented and all our walls and rim joists sprayed over with 3” of Closed cell and then the balance dense pack fiberglass we use 2x12 rafters and floor joists. Here is some facts. Energy prices are going to quadruple as the “greenie religion” forces everyone to use electricity only. Better to pay for insulation and air sealing today. Payback isn’t going to be all that many years.

I love your videos man, especially this one. Straight to the point to those with a low attention span and want a direct "yes or no" but then a full technical explanation. Keep up the awesome job!

Hello Mike and thanks for your very informative videos which were just recommended to me. We have a 30 year old home on Lake Michigan. It has a formed on site standing seam copper roof. The underlayment is Grace Ice & Water Shield (directly under the copper and sticking to the sheathing decking (7/8th plywood). This building has cathedral cedar ceilings and a non vented roof using blown in cellulose. Lightning rods on the ridge cap recently started leaking (broken calk seal) and some of the lightning rods had penetrated the Grace Ice and Water Shield under the ridge cap. This caused black mold on. the interior ridge beam. The fire retardant in the cellulose limited the mold - but the ceiling cellulose near the ridge was wet from condensation. The temperture at the copper was measured at 140F wile interior a few inches away was at 80F. We are removing all of the ceiling cellulose and replacing it with closed cell foam. The insulation contractor wants to install 6" of closed cell foam (icynene) directly to the underside of the roof sheathing. This would create decking encapsulated by Grace on one side and closed cell foam on the other. There should be no moisture in the plywood but also no way for any trapped moisture to get out. In one of your replies you indicated that this situation should be dealt with using "sheathing membranes". I did some research on sheathing membranes and it looks like they are just an impermeable vapor barrier? deltaacademy.dorken.com/resources/the-fundamentals-of-sheathing-membranes-and-air-barrier-protection/ Can I have my contractor spay closed cell foam directly to the bottom of the sheathing? Or we need to stick a sheathing membrane on first then the foam over the top? I really don't want to cut holes in the house to vent the roof because we live right on Lake Michigan and often experience high winds and driving rain and snow (and 18 foot waves) Lots of information, some want me to create a vented roof by cutting holes in the house and venting the ridge cap because they say the sheathing must be vented to dry and cool. I'm a licensed engineer (not a building engineer) and find conflicting advice. Thanks for your help.

A so true statement just because it is leaking in one place that does not mean that is the origin of the leak.

I really appreciate your approach to these videos. Concise, thoughtful and informative! After running a renovations business for a little more than 20 years now, I find myself building small-ish cabins for use as long term rentals as well as to sell. Looking to keep my costs low, I have looked to an idea that I used about 12 years ago on my own house build with a semi-vaulted roof system. (Scissor trusses) To obtain the required R value in the heels of the trusses, I was forced to use spray foam. After weighing the costs, I ended up using two layers of 4 inch blue Polystyrene foam insulation attached with quick -forming adhesive and recessed about an inch from the sides of the trusses cavities. Then, I filled those gaps with spray foam and added (approximately) 2 more inches of spray foam over top of everything. The Polystyrene boards were acquired from another job (re-doing a metal flat tar roof on a Home Depot building) so it saved me some serious $$. I too thought that insulating the roof deck would be advantageous over insulating the ceiling, and it has been maintenance free ever since. I was concerned that the minimal contact of the Polystyrene to the roof deck would be an issue, but it has been fine. Roof is a 4/12 with tar paper underlayment and 3 tab asphalt shingles in Edmonton Alberta. Any thoughts on this? Love your channel - liked and sub'd!😊

I have watched 20 videos and asked about 10 questions. I am finishing my 2nd floor cape in MA with a 12/12 roof with closed cell insulation ONLY. Rest of the house is open cell. I feel 100percent confident that its the right thing to do. I dont know what it will cost but it doesnt matter. I am looking forward to a great envelope protecting me from summer heat and winter cold.

Great video - thanks! Good to have solid info like this....Ive had many discussions/arguments over exactly this! I Had Closed cell sprayed in my attic roof deck and walls - in a 100 yr old wood stick frame house. It tightened everything up and Ive never had a problem since. It has paid for itself on my heat bills over 4 years.

Man what an awesome vid and explanation. All any of us want are common sense answers backed by rational data.

Glad to have that question answered. That made sense. Thanks

I guess you can add that closed cell is IRC code required in the United States for any unvented attic where the spray foam is applied to the underside of the roof deck.

Unfortunately where I live in the south termites are absolutely out of control and you don't find the damage until it's far too late. I have open cell foam and all of my house, but dearly regretted given the circumstances

Just found your channel. Good info. Somethings to mention. Closed cell in this scenario needs to be air tight with no air leaks through to roof sheeting. In my experience, air leaks in cold climates can drive enough moisture to cause structural damage from rot. Also ice dams can be an issue. We've had good luck with using baffles to create 2"+ ventilation space and thus maintain a cold roof while still gaining the advantages of closed cell foam, the added rigidity, the conditioned attic space, much less ice damming and, for me, accessible ceiling systems. The baffle idea seems like common sense to me and to the installer I've used on multiple jobs but I've never seen it mentioned in any foam industry info. Wonder why?

I think you made a good case @7:30 for not using closed cell foam. Once you encase the roof deck in closed cell you would have no way of knowing if your roof is rotting away until your shingles start to fly off. Sounds like cutting the roof deck with a skilsaw might have been avoided if the leak was detected early. I like the idea of open cell for that application, closed cell everywhere else.

Absolutely. Matt Risinger utube supports very similar procedure.

We have to have some type of ventilation in attic spaces by code in Michigan. Mechanical or passive ventilation your choice. With proper ventilation your shingles will last longer and not blister up. I have seen house's roof sheeting rot from spray foam and no roof ventilation. Currently ripping out finished spray foam basement. They sealed the masonry. Masonry loves to wick moisture. Condensation built up in blocks over time. Till it leaked in basement. The masonry needed an area above grade to dry moisture out. With roofs the issue is condensation. I tell people to make sure they have roof vent baffles installed before spraying foam.

Half way through my remodel i decided to swtich to nonvented attic with spray foam. I have a metal roof no penetrations. The plumbing vent goes out the siding near the peak then up above the roof line per code. If i did it again i would have used zip tape over the rafters to protect from nail holes. I also would have used zip roof deck. Im not a pro builder but i do think things through. Fortunately i used a metal standing seam roof instead of shingles so my decking ahould stay dry.

Great video.. I never understood the logic behind people saying open cell would be helpful in the event of a leak.

My builder said he only sprays open cell because of yrs of experience with both. He's had way more issues, both short and long term, with closed cell. I do know I have leaks and have no clue where the source is. My house stays a consistent temp yr round and my electric/gas bill stays relatively cheap compared to my old house and other people I talk to. My attic is unvented conditioned with 4" of open cell foam.

Peel and stick the sheathing to seal all the nail holes and control moisture intrusion. Spray a drainage coat before the foam.

I feel sorry for roofers and homeowners with spray. Most roof decking needs to replaced at some point, a lot of bad roofers out there. How hard is it going to be to rip that ply off there to replace? It’s going to be super expensive and difficult. Then you’ll have to reinsulate. Traditional insulation in areas that need access for service is a better option long term. Plus, I’ve seen a few bad spray jobs that owners were getting sick

I know this video is two years ago but I am just getting into the spray foam world. Had lots of people talk about needing to install some sort of roof baffles or some sort of ventilation. From watching this video it appears that that is not the case, correct. Spraying UPC 2.0 foam, living in Palmer Alaska. Thanks!

Recently had open cell sprayed in my attic. Noticed a leak during a rain storm shortly after due to the expanding foam pushed off our ridge vent. I had all 3 ridge vents removed and shingled over the opening. Problem solved but it cost the spray foam company $675 for this work. Ridge vents should be removed prior to spraying.

This video is better than you even realise... Closed cell simply does not absorb water.

did 4" of closed cell and that stuff is so strong that i feel like the house almost doesnt need sheathing.

This is a question I've had for since I decided to go spray foam. Thanks.

I'm wondering if there could be a condensation issue in colder climates, if any research has been done how this practice holds up to the test of time? A life long carpenter and builder I think having air flow between sheathing and insulation will alleviate the chances of condensation condensation.

Building Science Insights: To Vent or Not to Vent watch this he is an authority

Using closed cell foam in an unvented conditioned space has a big caveat and could be bad if the roof isn't done correctly. If you have a conditioned attic space then the roof is no different than an exterior wall assembly. If you use closed cell foam on the inside it acts as a non-permeable vapor barrier on the inside. This means that the outside of the wall or roof needs to breathe all the way through your layers of your assembly to the closed cell foam below. This means no peel and stick water and ice shields on top of the roof sheathing. If you do that then you have your wood roof sheathing sandwiched between two water and vapor impermeable materials. Bad idea since no system ever keeps 100% of moisture out. Very tiny amounts of moisture will get into any system but it will do no damage if it has a very easy exit. That is why any system should only have one vapor barrier on one side. Closed cell works well for walls because you have a rain screen material like siding that keeps most of the moisture off your outer wall surface with a small gap or drainage plane behind. Then your house wrap is water resistant but vapor permeable. This vapor permeable wrap allows any small amount of moisture that does get into the wall system to get back out once it is stopped by your impermeable closed cell foam. So closed cell foam for your attic is fine as long as you use a similar exterior system for your roof. Just use a vapor permeable but water resistant underlayment for your roof system.

How does the roof dry to the exterior? Most roof papers are not breathable air barriers the same as say a tyvec. If the roof deck is not breathable there is where the problem comes into play. I have been in the insurance industry for over a decade and seen numerous roof systems rotted because of spray foam on the underside of roof decking. And most shingle companies will not warrant the shingles anyway. That is probably why the engineer put that disclaimer in ther

Can you use close cell on 1/12 pitch metal PBR roofs.( in south east US) Have perused your vids but can't find anything spacific. Thanks for your ethics's just wish ALL spray foam contractors had your integrity and desire to educate others. As for as I'm concerned that is what transparency is meant for.

Let me be clear: YOU ARE CORRECT. What is amazing is that here in florida they STILL buy into the myth. At least the folks I have had over to my home for spray foam quotes.

I believe one important Building Code detail... as Part 9 of the NBC is being cited... you don’t mention is the requirement for a vented air space between the top of the insulation and the underside of the roof sheathing. I’m not saying SPF cannot be installed in this location. However, since no vented air space is being provided and most jurisdictions (Cities) must follow the prescriptive Acceptable Solutions listed in their Provincial Building Code, the use of an Alternative Solution may be required. I highly suggest the local Building Inspector is consulted before SPF is installed to determine if an Alternative Solution will be required.

Your videos have helped convince me that an unvented condition attic is the way to go. We are going to put new asphalt shingles on just prior to spraying closed cell foam on the rafters. What kind of underpayment should we use?

I don’t know why I can’t stop watching your dam videos.

I keep hearing conflicting info on putting foam directly to a roof deck. Some people insist you need an airspace there to keep the roof deck cool.

Thank you for making this video. Exactly what I needed.

Top shelf educational vid ... thanks again for these thorough vids and explanations

We recently completed a 12/12 pitched roof with the axis east and west for future solar. Direct southern exposure and the plans specified closed cell foam on the underside - no ventilation. I've been doing this for almost 50 years and the thought of a cathedral roof with no 1" continuous ventilation from soffitt to ridge vent used to be heresy, but now is the preferred method. I have been in many an attic that is suffocating in the summer heat, and the old 3 tab roofs would literally curl up at the edges like bacon and then a stiff wind would bend them up and over at the next edge. My concern is what roofing can stand up to the south sun with an insulting layer under that allows no heat dissipation? You mentioned 'ice and water' as the underlayment and the specs did note the roofing material needed to be approved for this application. I'm in Seattle, so not so cold and not so hot, but plenty of water. In addition, our building inspector mentioned the dew point as the main factor in negating the need for ventilation. I have a roof interior coming up for insulating and want to be convinced that this has stood the test of time and I'm just ignorant. In the 80's we went thru a period of maximum building wrap, sealed windows, caulking everywhere and vapor barrier on the inside, but the exterior envelopes leaked, the insulated walls could not breathe and there were whole blocks of apt buildings requiring residing in less than 10 years. It was a major problem up and down the west coast from Canada to California. I subscribed and am working my way thru your videos...Thanks for all the info. I know this is part of your marketing but I also know when someone loves their job.

You can't use asphalt shingles. They seal eachother in with tar strips. They are referring to cedar breather and cedar shake roof shingles that allow moisture to condense and evaporate from under the shingle back into the outside air. Otherwise you need a vent beneath the shingles making the sheathing the shingles are attached to the same temperature as the air outside

Closed cell on the bottom. Peel and stick or fluid applied on the top you I’m pretty sure you will NEVER have a problem. Thoughts?

Have you ever spray foamed gambrel roofs? Would like a video in that maybe talking about pros and cons

What about 4:12 or greater invented metal roof with high heat peel And stick underpayment as a roof In Florida. Was looking at 2”closed cell

They are assuming a 'drying season'. And they are assuming everywhere has that when they say it can be used everywhere as long as the pitch is greater than 3/12. That is just not so. In my particular area which is a temperate coastal rain forest things that wet just don't dry out with our average of thirty days or less of actual sunshine (combined with winds over 100 mph and 170 inches of rain). I am sure there are other such climatic zones in North America. Engineers and architects have a long history of failures so I just wouldn't be comfortable with any blanket statement from them and skeptical of particular local advice. I can show you one failure after another in our small community alone that was caused by bad design from 'certified' engineers and architects. When you combine modern building materials and water you have a large problem. Imagine six months of wet on OSB!! Then add it some freeze thaw cycles.... Spray foam is a good thing in limited situations but allowing a structure to 'breathe' in all but desert conditions is very important. The other new drawback I hear of and see is over the long haul the foam both open and closed 'shrinks' away from the dimensional lumber causing condensation where those openings lead to a cold external surface. I will be much more comfortable when I have seen forty years of existence of any brand of foam used successfully in tough climates. Always and interesting topic.

Great vid, very helpful. I'm embarking on a closed cell job for my roof deck. Two quesitons if I may! 1.) Is adding stregth to roofdecks for snowload a universal benefit when applying at least 4" of closed cell? 2.) We just completed some sistered rafters to the attic roofdeck. New lumber to old rafters. Should the new lumber be dried to a minimum moisture before spraying foam?

I would assume a roof with lower than a 3 pitch would have EPDM or greater roof covering and would allow for the same /similar detail.

So if closed cell was applied, I’m guessing you wouldn’t use any iceshield beneath the shingles? I can see the inspector challenging this lol. At the same time, although I completely agree with your argument, one would never really know when there’s a breach in the osb sheeting, beneath the shingles.

I seen metal buildings with flat roofs which spray in foam insulation if I built a metal building I would do this spray in Foam and insulation and I would cover it all up with metal It's a metal roof if you can't find a hole in a metal roof you do not belong on that roof please comment back if I am right or wrong thank you I used to do roofing for many years burn down rubber roofs Hot roofing jobs And also shingle jobs I used to find the holes in the hot roofs and the burn down rubber roughs before I found the shingle week a less it was a single missing or just a natural HOL E in The Roof or a less it was in the valleys or around distinct pipes or around the chimney every so many years you're supposed to go up there with a bucket of gunk and re do them thank you for this video

You mentioned a resource indicating it was safe to use CCF under roof decks on 4/12 or greater shingled roof….. What about low slopes roofs. Say a 2/12 roof using 45 mil TPO membrane ? Typically residential manufactured homes with TPO roof membranes are not glued down. CCF would be great for strength on an older structure, but what about future roof leaks? I should say this is in Florida. My home was narrowly missed by hurricane Ian.

Seems like it's a condensation point seems like a bad deal We're the warm and the cold touch It will condensate

What an amazing explanation!

You are an awesome tuber, THANK you for getting to the point strait off, for those who just want tje answer you did us a huge service. Ill subscribe for that

Does this hold true for metals roofs as well? I have an 8/12 pitch on a new build and have ice and water the entire roof prior to metal going on. No strapping between roof deck and metal. thanks. In Quebec (cottage).

Code requires closed cell (IRC 2018 & 2021)

Well in my local building code change this to you can't use closed cell on roof underside and encapsulating the rafters. The reason being there was one or two roof collapses because of a poorly maintained roof and the leak over decades had rotted the sheathing and rafters and there was no signs of a leak inside, so no one checked. You can however use open cell because once the foam gets saturated then it would be visible inside that you had a leak and would then go up and inspect the damage and make repairs, plus it was a good idea to replace or dry out the damaged foam. Also our snow load where I live is 62 lbs per square foot which is also a factor. You say these engineers certify that product under those applications, well sure they would, but a poorly maintain roof would not have a bearing on that certification, that's on the owner to ensure their investment is protected. So I guess one or two dummies wrecked it for the rest of us.

Best overview on the topic..thx😊

I live in the south and have an older house. I have a ridge vent and side draft exits, do those stay? Can i also leave the blown in insulation that's already there on the floor? Would you recommend closed cell?

Jury is still out on this as it is too new. Engineers are wrong a lot as everything works on paper. Every hot roof I've encountered have moisture retention issues. This will cook shingles but not affect metal, tile, or slate. Will probably cook synthetic slate. Buildings need to breath or you get sick building syndrome.

What about open cell for the underside of an EPDM flat roof? I assume this means the roof assembly needs to dry to the inside during all seasons which requires proper HVAC maintaining low RH in the dwelling.

Man I love your Channel. Great information right to the point and I can tell with alot of experience. Thanks

Wow, I love your video. Only problem is that I saw it too late. We just had our roof replaced with aluminum shingles. The underside of our roof sheeting is insulated using closed cell spray foam. The Installer claimed that he could not put the Aluminum Shingles directly on our existing plywood. He took off our old shingles and weather barrier and add a false roof over our 12/12 sloped roof. And in doing so he neglected to raise the flashing around our cultured stone chimney. As a consequence, to his actions, we now have water entering our home where the closed ends at the lower edge of our roof. My question is could aluminum shingles (which vent extremely well) be placed over a roof that has been spray foamed?

Awesome Videos you’re doing your community a great service thank you! Question- when you talk about the case with the man with the 12/12 pitch going to the 4/12 and water getting underneath the shingles… why would they have had to apply more spray foam when doing the repair? Wouldn’t the old closed cell foam remain undamaged and flat against roof deck so that the new piece could simply been placed flush right over it?

They said it needs to be able to dry to the outside. Does that mean there are situations where you can’t do a mental roof and spray foam?

Great info, earned a sub from me. Really like that you give an answer right away then go into details for the rest of the video. Joseph Lstiburek does some great videos that go along with what your saying. Keep up the great content

Can you do a couple layers of Closed Cell Spray foam as the vapor barrier and finish up with 2 or 3 layers of Open Cell Foam

Exactly the evidence.. Information i was looking for. Thank you Will look into it more

Well, wish you good luck to replace roof sheeting glued to closed cell...

Colorado code requires a minimum 3" to achieve vapor barrier.... sooo technically you could spray 3" closed. get your vapor barrier... then I suppose no harm to spray another 10" of open cell..... not sure cost of open and if this will get you lower costs.... i just stick to closed cell.... also...... Ice and Water shield !00% of roof you will eliminate any issues and I feel is best roof detail with closed cell below

Can you use 2" of closed cell then fill gap with open cell? I have an I.C.F home basement, and 2nd floor 3rd floor is a mix of 2"x12" walls and 2"x6 walls ,I'm going to have a condition attic that is cathedral type , the contractor I'm looking to use is recommending open cell with the thought that a void in the 2"x12" wall area and possibly the 2"x6" wall will create a bad echo ??

Keep in mind that roofs with a 3:12 pitch require two layers of asphalt paper under the shingles. I would be very careful about using closed-cell on less than a 4:12 pitch. What you fail to understand is that the closed-cell foam provides a moisture barrier under the plywood (like a vapor barrier). So any water that makes it to the plywood will be trapped between the ashpalt underlayment (which is a vapor barrier) and the closed foam insulation. This will impede the plywood from drying out. So your assumptions that all water will just drain off are incorrect. All water has to do is get under that asphalt paper and soak the plywood. This can happen if the roof is not sheathed and flashed correctly. The advantage of a vented attic is that if water does get to the plywood, the plywood can dry out from underneath air in the attic. That is a key difference. Putting in closed cell insulation in the roof can be done safely and it is a great insulation system, but if human error comes into play, it can rot large sections of the roof before it is discovered and that is why it is not widely used. Presumably, if water got under the 15 lb asphalt paper and soaked the plywood, if open cell foam insulation was used, then the plywood would have a way to dry out. What we are talking about here is what happens when their is a roof failure. The closed-foam system can greatly increase the scope of damage caused by a roof failure. Also remember if the roof is a tile roof, then the cost of repair can be significant.

You address a shingle application, what are your thoughts about a steel roof at 3/12 with closed cell? Thanks

The problem with any spray foam most the guys doing it had drove the price so high it’s just unaffordable. I don’t know if the materials has raised that much over the years or not. I suspect greed is the reason more so than anything. They’re pricing themselves out of business Plus the smell reputation it’s had in the past scares people away. How many people are willing to chance putting it in a 2 or 300 thousand dollars home ? Only to end up living in a camper in the driveway. For the price everyone wanted to do my garage/pole barn I could insulate it a little over twice with owning Corning fiberglass.

Thanks very educational

Question. Is there an advantage to 1" of closed cell followed with 3" of open cell? As opposed to only 2" of closed cell? Some installers are recommending this application mainly due to cost of material. THANKS!

which is better? there is only one way to find out "Fight"

Thanks for your videos, great information without the bs.

My neighbour just had open cell foam installed - I'm located west coast Scotland very wet, damp, humid conditions most of the year, wettest and windiest place in Europe... Closed cell sounds better to me... Can you tell me about off gassing with open and closed cell please, you seem to know your stuff, thank you in advance.

How about a good quality metal roof with the higher quality snow and ice shield over the entire decking

What about a flat roof with modified bitumen torch down roofing? When they're talking about three and twelve they're specifically referring to using shingles, right...?

Great video! Just the info I needed. One question: see any issues using zip system roof deck and closed cell under?

I'm an engineer and I agree that this is ok but using an explanation of "because an engineer says so" is just circumstantial inference and not a technical defense. I would have liked to see the technical explanation included. I know there are minimum thickness requirements based on location to prevent dew point condensation and different things like that.

What about a 2:12 slope but a membrane roof?

I have a small leak from a solar rack and the closed cell has ultimately kept a ton of water out. I have been trying to get a contractor to simply fix the roof and it is a nightmare!

What about using spray foam on the underside of a metal 5/12 roof with no sheathing.

Hello Mr Jones: I have a couple of questions.. I'm having a new all metal building put up.. The beams, girts and trusses are galvanized, do l need to prime them with something prior to spry foam? #2 How thick should the foam be on the under side on the roof? Non vented roof.. Thank you.

Is it 3:12 and up or 4:12 and up? In the beginning you said 3:12 but at the end you said 4:12.

Should I spray foam my flat roof? Its 2x6 joist with existing shingles

Thanks for the video. We just closed on a house in the Seattle area (Marine 4) and our roof is going to be replaced along with some of the sheathing (mold). We need to fix the insulation to help keep condensation out and was considering going closed cell foam so we can use the attic for conditioned storage. How does CCF on the rafters do in the wet environment? I was reading in your comments that vents would be better to not be there. Our alternative is to replace, seal and blow in to R40ish to keep the moisture down, but also read that over venting in the Marine 4 environment will actually cause more condensation. I just want to do the best practice and hopefully avoid these issues. We have a lot more moisture than Regina plus we have 2 skylights that I am worried about the low R causing condensation in the winter.

People don’t understand that closed cell foam seals. It’s used under slab floors and stops moisture. They hear foam and don’t really understand the nature of closed cell spray sealer. Maybe the name should change.

I have one stupid last questions. I promise this will be my last. I am following as I understand it your advice. 2" closed cell on my foundation slab, 2-2.5" in my wall assembly (I will have Zip R-6 a sheathing), 3" closed cell on roof deck in my conditioned attic. So here is my stupid question. Should I also go 2" of closed cell between my ceiling and my conditioned attic? I am sure the answer is yes, but trying to cut some cost and just don't know. If my attic roof deck is closed and my walls are closed, is it worth doing in the ceiling of my ranch home? Thanks, sorry for asking so many questions, but I trust your opinion.

How about preventing the shingles from burning off of the roof. Air flow is necessary!

We have cedar shakes on the roof and thus it's vented, using gable end vents. Does the use of the shakes prevent closed cell spray foam from being used on the underside of the roof decking?? Thanks

Thoughts on renovation application to a 100 year old plank deck with multiple questionable or moldy areas underside? The drawings seem to apply to new construction with no reference to old homes and integration of vintage and modern practices. Plank spaces knot holes and other openings and less than new kiln dried lumber would seem to pose problems. Sealing in 100 year old low slope 2 x 4 roof and rafters as well. IN those cases would a plywood or other baffle base be warranted to provide ventilation and drying space from underside as low slope roofing does not allow drying from the exterior. I would like to see these legacy home issues addressed directly.

Thank you for your videos! I enjoy learning from you! Would this also apply to a metal pole building? I want to have the walls and inside roof metal sprayed with closed cell foam, but I am concerned about ventilation. This building will eventually have heat, but no A/C. Do you have a video already on this situation that I may have missed? Thanks for your assistance!

what about vapor venting

I'm planning on building a metal building home, all metal structure and metal roof, in Louisiana. It is a 2 story home with the entire roof inside vaulted and will be open to the inside of the house. I plan on using 2-3 inches of closed cell, sprayed directly to the metal, on the outside walls and 3-4 inches and the roof. I live 3 miles from the coast and we get lots of rain and sometimes flooding. I'm wondering about mold issues if we end up with standing water inside the house. Will mold grow on the foam? My other questions is the metal roof, what if I get a leak, how would I be able to find it or is this even a concern on metal roof with closed cell sprayed directly to it? I love your videos, they are very informative!

Amazing videos, I'm building my new home and was hesitant to go with spray foam due to sketchy contractors. I wanted to hire you so bad for my job but it looks like your in Regina SK. I'm in Calgary AB is there anyone here you know that is as great as you?