[Kolyan2k]

Anyone done it in their attics? I have mid 80s house with original fiberglass batts and cellulose on top (in New England). Not sure what the R value of that is. But this past fall I had mice issue. They somehow get to attic (i found no holes anywhere), very annoying and some die there. They love all this cozy insulation.
So I was thinking removing all that nasty stuff and spray foam all rafters (2 inches closed cell and then open cell) making it R38. Contractor said R49 is not necessary and waste of money.... Total for this job is $7k. Not sure if it's worth it, seems like it will add zero value to house. Is that a stupid idea?

[Kolyan2k]

With all that cellulose its nasty in attic, can't do anything, can't find anything, can't even set a mouse trap. They all crawl under the insulation

[Bc2005]

I’m in Virginia and last year we had the attic cleaned of all old insulation, and the roof deck insulated with Icynene open cell foam at R38. The attic is now completely air sealed and insulated with foam. The open cell foam allows the roof deck to “breathe” and slowly let moisture escape.

I’ve found that during the last couple of weeks here, when outside temps were about 15-20 degrees, the attic is only a few degrees cooler than the inside of the house. Our heat uses a gas boiler and radiators, so we added A/C and the ducts are in the attic. Now the ducts are in conditioned space in the summer, so the A/C also works better.

Depending on the size of the house, $7k doesn’t sound too bad if they are also going to remove the old insulation. That old cellulose is really dusty and dirty, and has a lot of volume that you have to bag up for disposal. It’s hard to compare prices since your open/closed cell foam combo would be more expensive than my open cell foam. I also had the walls spray-foamed in a new two-story addition.

[Kolyan2k]

Yeah i have AC in attic as well. But I also have solar panels and don't even pay for it. Yes I read alot about open cell vs closed cell stuff. But it seems that everyone is doing 2 inches of closed cell to make it air tight followed by open cell. (Cheaper then doing R38 closed cell only). I think they also need to paint open cell with fire barrier paint. (Included in estimate)

[DETRoadster]

Be careful and do your research on the type of foam that is used. Take it from me, as someone who did NOT do his research. We got talked into some eco-groovy waterbased non toxic bullshit. Well the shit ended up shrinking by maybe 10% to 15%. So now every stud bay around my entire house is filled with bricks of foam that pulled away from the studs and the sheathing. They just sit in there, essentially worthless, as there are huge air gaps that let cold air pass right on by. Total fucking fail.

[Bc2005]

Fire/flame barrier paint is required in an attic if you plan to use it for storage, but I decided it was time to keep all the junk out of there.

The code says you must have a flame barrier between the foam and any occupied space. If the attic is not used for storage (the HVAC does not count) then the Sheetrock ceiling in the house below is your flame barrier. When you use the attic for storage it becomes occupied space (I guess) and you need to have the barrier sprayed on the foam.

[Kolyan2k]

I am not planning to use for storage (not now) but I think barrier paint is included in price. They will send me specs for foam later

Alittle worried about roof rot.....I've read alot on this issue. Also some suggested having dehumidifier installed in attic to avoid moisture problems

[Kick 6]

I built a cabin and had the entire house sprayed with spray foam. The most our power bill has been in 4 years is $125 and that is with full time occupancy. Most months it is around $80. Anything I build from now on will have it. Being air tight makes a huge difference.

[paquet]

I'd just like to point out that R39 seems really low...

[Kolyan2k]

R38 is the code standard for attic. R49 is optional and roughly another $1000+ on top. Insulation guy said it's a waste of money for unoccupied space

[Bruuuce]

I just had a quote done for similar reasons. I have a low slope roof and around 2500 sq ft of roof to do. Part of the roof was injection due to a vaulted roof. Price was similar to your 7K, always hard to compare. I also had other parts of the house in the quote and mentally broke out those areas to say 7K just for the roof.

I have read the good and the bad reviews as well. Will it add value, first I guess it should be insulated, so how its insulated may not change the value. But it could add a perception of better value over a house with out it... Who knows. I also doubt there is a price performance formula that will work out, 7K is allot to recover with $5 of savings a month... Just made that up.

So I am considering it as well and looking forward to other thought.

[2000cs]

We have it throughout our house. Icynene foam. House is cinder block exterior, filled with foam, and the ceiling is foamed. On a slab so nothing there except the vapor barrier.

2500 Sq Ft in FL. Electric heat pump (2 units) heating and cooling. Always running as spring and fall are each about an hour long here. Max electric bill under $200. January bill (lots of heat) was under $100. Feb likely higher but not much.

House is tight and comfortable. If I was building from scratch I’d foam it; retrofit is harder to justify because you have higher cost, and it isn’t clear you can seal walls, windows and doors properly.

It is usually best to start with caulking windows and doors, foam around windows if you can get the trim off, etc. Add insulation to the attic. Then, if you still want to tighten up, add it to the walls. Of course insulate any time you open a wall (remodel, whatever). Probably cheaper to fill in missing cellulose, then lay bats across the rafters over existing insulation, than to remove and reinsulate. Unpleasant task but definitely DIY if you want to.

Foam won’t prevent pests/rodents, they can easily nest into that as well. Solve that problem by properly plugging entry points.

[ryan stewart]

I havent done the closed cell spray foam but did do the loose fiberglass. My house already had fiberglass but the builders grade stuff and not enough of it and not that well spread.

I found that home depot has the equipment to blow in the loose stuff (comes in compressed fiberglass bricks and the machine chews it up) and if you bought 10 bags the machine rental was free. So I loaded up and ended up doing what was the equivalent of R49+ in my attic and really hitting areas where there were breaks in teh drywall and it made a pretty big difference upstairs.

ONe note though, be careful around the soffits or have the baffles put in so you dont block airflow, my dads idiot friend copied me but blew it all into the corners and ended up making it worse by basically sealing his attic and it would get superheated, had to clean it all out of the edges.

[Kolyan2k]

I dont have soffits for some reason. I guess that's how they built in 80s. Contractor said they use Carlisle foam. I am still not sure about R49 for 8k or R38 for 7k.....

I wonder what R value is done by Mass Save (state free insulation program). Previous owner did, but it doesn't say what R value is. I might call the company and ask. I definitely don't want to down grade if I have R49 already.

Ps. I am not doing it for savings on bills. I am just sick and tired of that cellulose crap. Can't go to attic cause it's full of insulation, can't see anything, had mice issue last year and vasps. Cellulose makes it next to impossible to do anything in attic.

[ryan stewart]

I put elevated planks in wood boards over my insulation so that I can store stuff up there.

Just know, like somebody else said, you're still going to be dealing with the animals if you don't resolve how they are getting in.

[M5Rick]

Whatever you do don't let any dogs, cats or pets into the loft where there is fibreglass loft insulation,it's harmful to their small lungs.

[M-technik-3]

I'd suggest 2 inch closed cell and then just add the cellose back over it. I would check with MassSaves and get an energy audit and you might be able to get the blown in for a fraction of the cost.

Just noticed MassSaves came in already so I'd doubt you would be able to do it again even though you are a new owner of the home, plus they do not do spray foam at all that fall on the owner.

[Kolyan2k]

Originally Posted by M-technik-3

I'd suggest 2 inch closed cell and then just add the cellose back over it. I would check with MassSaves and get an energy audit and you might be able to get the blown in for a fraction of the cost.

Just noticed MassSaves came in already so I'd doubt you would be able to do it again even though you are a new owner of the home, plus they do not do spray foam at all that fall on the owner.

Yes. I believe they already did R38 in ceiling. But cellulose is basically the reason why I want to redo everything. I want to insulate rafters not ceiling (attic floor). Vacuume all cellulose out, trash all fiberglass, and spray rafters

[M-technik-3]

If you do the rafters with out soffits and a ridge vent your shingles will cook and curl. That is not ideal, if you are going for a semi improved space you will need to check on the code for your area and be careful of doing work and not pulling a permit. Towns need income and permits and inspections are a source of income for them.

I got nabbed but claimed ignorance and was lucky.

This is more what you are looking for https://basc.pnnl.gov/resource-guide...existing-roofs foam panels go on the exterior followed by sheathing then shingles. This way your asphalt shingles will survive.

[Kolyan2k]

Originally Posted by M-technik-3

If you do the rafters with out soffits and a ridge vent your shingles will cook and curl. That is not ideal, if you are going for a semi improved space you will need to check on the code for your area and be careful of doing work and not pulling a permit. Towns need income and permits and inspections are a source of income for them.

I got nabbed but claimed ignorance and was lucky.

This is more what you are looking for https://basc.pnnl.gov/resource-guide...existing-roofs foam panels go on the exterior followed by sheathing then shingles. This way your asphalt shingles will survive.

I did read about cooking shingles.....I know when you insulate rafters with fiberglass, contractors do install air channels, but that's not the case with spray foam. Spray foam is sprayed directly to wood sheathing and that meets building code. So I have no clue if cooking shingles is real or myth. That's how many or most contractors here insulate.

Also as I said before, I don't have any soffits for some reason. I have ridge vent and gable vents on both sides of house. My current roof is about 10 years old now, looks new to me

[M-technik-3]

I would contact at respected GC and ask him a few questions or send a letter in to This Old House and see if they respond with an answer.

[Kolyan2k]

I've seen these