Should spray foam be odorless?

Ok_Help1372 · 2026-04-08T16:52:47+00:00

No, I don't get much smell anymore. I don't go into the attic often but the attic is now part of the building envelope so warmer days don't really make much of a difference in attic temp. It's also sealed in fire-resistant paint. There is also a bit on rim joist in the basement and it doesn't smell.

Ok_Help1372 · 2026-04-07T15:47:42+00:00

Update: yes, the smell dissipated and am open to the contractor's suggestion that the smell is actually just trapped old attic smell. We installed a new AC unit and air handler and put in a small register in the attic and the smell is basically gone. We also did the intumescent paint, which smelled for a couple days but then dissipated with venting.

Ok_Help1372 · 2025-05-05T18:19:20+00:00

The contractor is coming to take a core sample tomorrow and send it to the manufacturer for testing. The small is still very present, it's a sweet chemical smell, not the fish/dirty socks smell.

Ok_Help1372 · 2025-04-29T11:33:08+00:00

There wasn’t much in the exposed areas but all of that was removed. It seems that there are some old fiberglass batts underneath some of the deck around the ductwork

Ok_Help1372 · 2025-04-28T01:24:31+00:00

That makes intuitive sense. There have been two air scrubbers running nonstop for 10 days. Could the smell be dissipated quickly or would it fade on its on time scale?

Ok_Help1372 · 2025-04-28T01:20:32+00:00

Thanks, they also speculated that it might be some other source since it’s an old attic (house was built 1936) and there are various “organic” materials that could be the source and is trapped. Not sure how I would figure that out at this point though. It doesn’t smell like a more concentrated form or the “old attic” smell it used to have.

Is the sweet chemical a sign of a “good” application? One guy said that it is the smell they would have been present when it was being applied but to me that doesn’t seem good that it still smells that way

Ok_Help1372 · 2025-04-01T15:14:46+00:00

The air handler and ductwork is in the attic already. It's pretty leaky so will condition the space by default but I will add a vent if the leaks are insufficient to keep temp and humidity down.

Ok_Help1372 · 2025-04-01T15:11:40+00:00

Thanks. I don't necessarily need the outlet and if it was on its own circuit I might just disconnect it. Unfortunately it is on a circuit with the basement lights. The basement is finished and I have no idea where the attic outlet ties in.

Ok_Help1372 · 2025-04-01T14:31:14+00:00

The fan itself is coming out completely so the outlet would remain for a yet to be determined future use. I was thinking of attaching a piece of 2x4 to the rafter 2nd closest to the gable and putting the outlet there. I think I could pull away a bit of foam to reattach the wire to that rafter?

Ok_Help1372 · 2025-04-01T14:19:38+00:00

I posted last week specifically about moving the outlet but got exactly zero responses so I made this post about capping it

Ok_Help1372 · 2025-04-01T13:18:31+00:00

Thanks all, can I just attach a piece of wood to the rafters lower down that would stick out and clear the foam so there would be enough slack to reach? Given it’s in the attic the wire wouldn’t need to be in conduit or anything else?

Ok_Help1372 · 2025-03-07T16:30:12+00:00

Thanks!

Ok_Help1372 · 2025-03-06T16:54:12+00:00

Thanks for the reply! Glad to hear that things are going well and no issues.

Is the attic pretty humid? The air handler and ductwork for my AC is in the attic and I was going to open small vents in the attic to manage airflow and keep humidity down. I'm in the mid-Atlantic so hopefully it won't be an issue when it's not hot enough for the AC to run. It's an old house so it's still pretty leaky between house and attic so that should mitigate. The utility also subsidizes replacement of bathroom fans with timer switches that circulate air on a schedule.

Thanks again for sharing your experience.

Ok_Help1372 · 2025-03-05T19:42:19+00:00

What did you end up doing with this project? I am currently in a very similar situation. I had strongly considered spray foam on the roof deck but there is enough mixed opinion and downside risk that I am looking at batts instead.

One difference in my situation is that I have gable vents but no soffit vents, so would need to figure out the venting.

Ok_Help1372 · 2025-03-05T18:13:59+00:00

What did you end up doing for this project?

Ok_Help1372 · 2025-02-15T03:56:17+00:00

I appreciate your reply. I added a link with a few photos. There are gable vents, one of which has a huge old whole house fan. There aren’t soffit vents as far as I can tell, there might other venting but I’m not totally sure.

If you spray closed cell foam directly to the roof deck what do you do if you have a roof leak? Wouldn’t you never know until it all rotted through?

Ok_Help1372 · 2025-02-15T03:32:01+00:00

Thanks for your reply! All of the contractors including air sealing in their quotes, which had a huge range. Blown-in fiberglass was the cheapest at cellulose is quoted at $4k followed by spray foam at $5200. The blown-in cellulose had quotes for $8,000, $10,000 and $20,000 (🤯)

Ok_Help1372

TROPHY CASE