Spray Foam ceiling or roof??

[Repsolracer22]

Getting closed cell spray foam done in 40x60 pole barn. Doing 2in on walls and 3in up top. But for the longest time I was under the impression that you spray the ROOF and seal up the ridge vent and soffet completely. But this spray foam guy I talked to today said you can do that OR you can put up a steel ceiling and spray the back of that and be done. Would save money and your attick would perform just like an attick with the vent setup.

thoughts?

it would save money to do the ceiling VS the roof deck but not sure if its the way to go. I like the idea of the roof being done so the building is one sealed envelope at that point and no stink bugs can get in!! But the ceiling foamed is a couple thousand cheaper.

 

[Silver Surfer]

I am in the process of getting my first pole barn built and trying to figure out insulation as well. I spoke to local a spray foam guy on the phone. I was not planning on doing a ceiling. He wanted to use 6" of open cell foam on the roof and the gables. I asked about closed cell and he said that it would not allow any moisture to wick away and evaporate. Both closed and open cell still offer and air tight seal, which is what you want.

 

[Repsolracer22]

I am in the process of getting my first pole barn built and trying to figure out insulation as well. I spoke to local a spray foam guy on the phone. I was not planning on doing a ceiling. He wanted to use 6" of open cell foam on the roof and the gables. I asked about closed cell and he said that it would not allow any moisture to wick away and evaporate. Both closed and open cell still offer and air tight seal, which is what you want.

Interesting. Never heard of that. Not sure how moisture would even generate if you sprayed closed cell directly onto back of metal.

Never heard anyone say that open cell is better in any scenario except the price. Every time I turn around there's a legitimate sounding differing opinion from someone. Damn confusing. Can't decide

 

[Repsolracer22]

any other opinions?

 

[sands35]

http://www.greenbuildingadvisor.com/blogs/dept/guest-blogs/flash-and-batt-insulation

As for the ceiling, it doesn't make sense to me to spray the undeside of the roof deck directly. That would be a nightmare to repair the deck when the roof needs to come off. What makes sense there is to spray foam the topside of the ceiling drywall to seal up air leaks, then put loose fill on top of that. The other alternative is to simply caulk, tape and foam-in-a-can up the ceiling pierces

If you are going to do flash and batt, you need to ensure the contractor and the people doing the finish work know what they are doing. If it's not done properly, you have created more problems then have been solved compared to simple fiberglass insulation. The foam needs to be the correct thickness to avoid condensation, the interior treatment needs to allow for vapor transport or the inside will rot. The outside drainage plane needs to be well done or the exterior sheeting will rot.

 

[Diesel Dan]

Never heard anyone say that open cell is better in any scenario except the price. Every time I turn around there's a legitimate sounding differing opinion from someone. Damn confusing. Can't decide

Open cell is better for sound deadening from what I recall.

 

[Rickcnc]

I did spray foam on the walls and cellulose in the ceiling.. work out well

 

[hockey88fan]

Getting closed cell spray foam done in 40x60 pole barn. Doing 2in on walls and 3in up top. But for the longest time I was under the impression that you spray the ROOF and seal up the ridge vent and soffet completely. But this spray foam guy I talked to today said you can do that OR you can put up a steel ceiling and spray the back of that and be done. Would save money and your attick would perform just like an attick with the vent setup.



thoughts?



it would save money to do the ceiling VS the roof deck but not sure if its the way to go. I like the idea of the roof being done so the building is one sealed envelope at that point and no stink bugs can get in!! But the ceiling foamed is a couple thousand cheaper.

Never heard of sealing off the ridge vent and gables.

 

[James-W]

I am certainly not an expert in roofing techniques, but I would say it is a bad idea to seal off soffit vents and ridge vents, or any type of attic venting for that matter. You want outside air to come in and circulate and then leave thereby getting rid of moisture in the attic. Sealing off the vents prvents that from happening.

 

[Gregg33]

I have a 32' x 64' x14' height pole barn. The idea of insulating it seems overwhelming to me, both financially and from a work point of view if I do any or all of it myself. I was thinking of maybe only insulating 1/2 of it (most of the work I do is in that half), but even then, not sure how to go about it nor would I really want to attempt to do the work myself. I wouldn't mind framing a small wall or insulating a framed little garage, but it seems a bit much for me, especially because I don't have any help and am not big on reno type work. I would think it would be several thousand even for materials.

 

[hockey88fan]

I have a 32' x 64' x14' height pole barn. The idea of insulating it seems overwhelming to me, both financially and from a work point of view if I do any or all of it myself. I was thinking of maybe only insulating 1/2 of it (most of the work I do is in that half), but even then, not sure how to go about it nor would I really want to attempt to do the work myself. I wouldn't mind framing a small wall or insulating a framed little garage, but it seems a bit much for me, especially because I don't have any help and am not big on reno type work. I would think it would be several thousand even for materials.

I was planning on insulating my garage myself until I got an estimate to have someone else do it. Their estimate came in $200 less than what I could've bought the material myself from HD or Lowes.

 

[hockey88fan]

I am certainly not an expert in roofing techniques, but I would say it is a bad idea to seal off soffit vents and ridge vents, or any type of attic venting for that matter. You want outside air to come in and circulate and then leave thereby getting rid of moisture in the attic. Sealing off the vents prvents that from happening.

If the roof is shingled I would think it lower the life of the roof.

 

[James-W]

I was planning on insulating my garage myself until I got an estimate to have someone else do it. Their estimate came in $200 less than what I could've bought the material myself from HD or Lowes.

I have heard this before and I wish I had gotten a bid on insulating my garage instead of doing it myself. Apparently, when these companies that do insulation jobs buy the insulation, they buy it in very large amounts so they get it for a much cheaper price than it can be gotten at places like Home Depot, Menards, Lowes, etc. It is always a good idea to get a bid on the job and then comapre the bid to what it would cost to do the job yourself. In some cases you will find it is in your best interest to hire it done rather than to do it yourself.

 

[Gregg33]

I was planning on insulating my garage myself until I got an estimate to have someone else do it. Their estimate came in $200 less than what I could've bought the material myself from HD or Lowes.

I came across the same thing when it came to building the barn itself. I wouldn't have saved much if I built it myself.

 

[TTTTTT]

Like many contemplating the same for insulating my gambrel trusses. A different project just completed an addition on my house with 10" rafters. Building dept said if I use bat insulation must be the usual venting from the soffit to the ridge or roof with vapour barrier. If I used closed cell spray getting at least R30 no venting required and no vapour barrier required. If I used open cell at 10" +/- , no venting required but they did want a vapour barrier due to the possible air flow to the warm side still getting R30. The open cell was about $800 cheaper, so i did this and a $50 roll of 6 mil vapour barrier. Its early but so far very happy.

I am leaning toward open cell spray foam for my 24'x44' garage/living space with the gambrel trusses. In the pic.

Dave

 

[Chris705]

Repsolracer22 - a couple questions if I may.

1. want to clarify type of roofing you have? Asphalt shingles on wood sheathing? or metal roofing with or without wood sheathing (purlins under metal)? Lots of other threads discussing metal roofs and spray foam.

2. could you give us a rough estimate of the original quote???? I will be going that route when I save enough $. I have a full attic for storage and will be applying spray to the underside of my sheathing.

 

[Jlbc212]

Insulating directly under a roof deck with asphalt shingles on top will greatly shorten the life of the asphalt shingles. The heat of the sun will bake those shingles, drying them out and cause them to curl prematurely. Having air circulation under the roof deck will help to cool the shingles and extend the life of the shingles.

 

[bsg]

Insulating directly under a roof deck with asphalt shingles on top will greatly shorten the life of the asphalt shingles. The heat of the sun will bake those shingles, drying them out and cause them to curl prematurely. Having air circulation under the roof deck will help to cool the shingles and extend the life of the shingles.

Super heated air from poor air circulation in the attic will cook the shingles faster than the sun will!

SIP panels have no air circulation underneath the shingles and as far I know there are no problems with the life of the shingle.