Closed cell foam insulation

[se2000]

Mold grows on organic surfaces. The cold from the roof will transmit through the rafters and the moisture will collect there and you will get rot. You also in your passes seem to have less material at the rafters. This is bad. Not today or tomorrow but down the road, you'll be kicking yourself.
Maybe get some 1 1/2" or 2" tuff R sheets and either cover the entire ceiling with it, then your sheetrock, you could even go 1/4" because of the foamboard backing. Or at least do the rafter bottoms with maybe a 6" wide piece and spray foam from it to the previous spray. That will give you a flat mounting surface and continuous insulation. I say go with the full sheets, tape the seams well or use tuff stuff to fill gaps as it should be cheaper and easier. The foil on the tuff r will provide radiant barrier also.
I saw in the website where they were doing walls, not roof and cutting it off. Not the same.

 

[sk8salomon]

So I can't help but wonder about all this mold & rot you talk about? Is this common on every house in America whether you have insulation in your roof or not? My house was built in 1940, the rafters are rough cut 2x4. The roof doesn't even have plywood, they used rough cut 1x6 back then. Over the years the 1x6s have shrank causing up to 3/4" gap between the boards. I could look up and see the bottom of the tar paper if that tells you anything. There has never even been any kind of insulation up there, ever! My rafters have no signs of rot, or mold, or anything that makes me feel the structure is not safe....& it's been that way for the past 70+years!!! My goals for using closed cell foam were a) add strength to the old roof by filling in gaps of 2x6s, b) insulate the roof because it's never had anything!, & c) air seal roof area as much as possible (never 100% possible btw). I can assure you that I have done all these things and it will affect my house in a positive way, 10 fold! I just don't see how all of a sudden I've done more damage and will affect the future of my already 70+ year old house, lol. I can already tell from being up there in the middle of the day it is at least 10-15 degrees cooler than before.

 

[sk8salomon]

from multiple sites of closed cell foam insulators...rafters!

 

[jynx]

What is the working time on this stuff? I'm looking at a 24x40x10 garage and wondering what kind of time I will have. Does it mix at the gun, so the gun is the only thing that could goo up? 2 kits should do the exterior walls.

 

[sk8salomon]

Yes, nozzles are the mixer. When you remove nozzle there are 2 nipples..you will like :0
I will measure what I have & let u know

 

[pillguy]

Sean,
Great work. I thought about doing it in my old house, but chickened out and blew 24" of pink foam for insulation. I may do this in the next house.

 

[jynx]

@sk8salomon hey Sean, bringing this back from the dead, but I was just looking at your post and want to make sure that I read it right. The stuff mixes in the nozzle itslef (Post 25) so if a fellow were to do a section and then have to stop to reposition or move a bunch of crap, as long as the tip was removed and the nipples cleaned off good, the individual components will stay in the tubing and remain "usable" until a new nozzle is attached. Say a few hours or even day or 2. I am going to start working on the barn, but it will be a wall, or section at a time more than likely. Thanks

 

[Clutchee]

Yes mix at nozzle- impingement.

Getting our house foamed this week- 8" on roof and 5" on walls.
This with the high seer ac unit....
Savings on $$ should be good.
Basically foam guy said by insulating roof thus not allowing heat to penetrate open space of attic will thus keep ambient temp down, then keeping whole space cooler.
Also allowing for better seal in outer walls and also keeping house quieter.