Question from Dierdre
Can you suggest an insulating spray foam product I can use around a window?
The code requires that window installers/builders fill any gaps with insulating material – caulk doesn’t count. They usually use the insulating foam, but my builder said he can use fiberglass instead. Do you think this would be better? With fiberglass, of course, I worry about any airborne fibers, but I guess if it’s sealed inside it wouldn’t be an issue. I guess the fibers couldn’t escape via infiltration of air through the building envelope.
Thanks so very much, Debra. And thanks for all the great work you do in general.
Debra’s Answer
Here’s the story about these insulating spray foams.
First, they are all alike. There’s not one better than another, so your contractor can use whichever one they want to use.
They are VERY TOXIC to apply. Like they should be wearing respirators and hazmat suits. But once they cure, these foams are totally NOT TOXIC. So you can have it in your house, but don’t be there while it’s being installed and air your house thoroughly after.
Be careful when looking for a nontoxic insulating spray foam because websites will say “nontoxic” referring to the end result, and neglect to tell you how toxic it is during installation.
Fiberglass would be much better.
This is very good timing. I’ve been looking around for a low-VOC replacement for a spray foam sealant to use for filling in small cracks in our foundation. All the non-toxic ones I’ve found are like Debra said, no-VOC AFTER application, but during… a different story. This is tough because it’s winter time and there’s no ventilation in our crawl space. I was wondering if its possible to use zero VOC caulking to fill in foundation cracks? ie. Safecoat Caulking Compoud?
COMMENT FROM DEBRA:
According to the Carey Brothers, authors of Home Maintenance for Dummies, YES, you can use caulk to fix cracks in the foundation of your house. But check with the manufacturer first to see if the type of caulk you want to use is appropriate for this use.
Thanks Debra! Great link. One of the distributors confirmed the safecoat would work in this instance!
Insulation products are just a balancing act of toxics and sensitizers. My family is sensitive to many chemicals, as well as man-made vitreous fibers (MMVF) like rockwool and fiberglass. If something isn’t done to totally air seal around the windows, then air transferring from outside to inside would bring particulate of whatever is in the wall, including fiberglass if it is put there.
Same thing with whatever insulation is in the walls or attic. If it’s cellulose (with whatever fire-retardants are on it), or a MMVF, particulate of those substances will migrate to the living space.
Everyone’s sensitivites are different, but cellulose and rockwool insulation are what created my family’s sensitivites.
I find it hard to believe these foams are non toxic when heated, as they will be in a house. Can you explain. Also don’t like the idea of breathing the rock wool etc. fibers.
I am using non toxic wool (Good Shepherd Brand ) that is treated with Borax and also silicone caulk as needed around the inside and outside edge to seal it in.
COMMENT FROM DEBRA:
Good. I love wool for insulation. In California, I used it to insulate all the exterior walls of my remodeled kitchen.