The foam insulation will burn

Are there any dangers associated with rigid foam insulation?

Is there a risk that the insulation made of polyisocyanurate or rigid polystyrene foam will release bad vapors / gases? I plan to insulate my bedroom from the inside (i.e., put the insulation between the studs) and I wonder if I will have to worry about smoke over the years.

My guess is that there isn't a problem as people use this stuff all the time and my vapor barrier is preventing any air movement anyway. Even so, it was brought up by a hardware store I called, so I would like some mental health checking opinions.

To edit : Since I could find little valuable information about insulating the inside of external walls with rigid insulation, I decided to use Roxul (fiberglass) instead.

However, to answer my question, I asked people and they pretty much scoffed at the fact that rigid foam insulation gave off fumes.


According to the Safety Data Sheet (MSDS) for TRYMER (TM) 3000 rigid polyisocyanurate insulation, there should be no problems (for this particular product anyway).

I also found the MSDS of an example Expanded Styrofoam sheet that mentions exhaust issues. However, this only applies to large quantities of "fresh" polystyrene stored in a "closed, non-ventilated area".

Fresh polystyrene contains pentane residues and when large amounts of EPS materials are used in a closed, non-ventilated area such as a semi-trailer truck, pentane can be emitted and measurable concentrations in the air.

If you know the product you want to use, it shouldn't be that difficult to find the appropriate safety data sheet on the internet.

Yes, foam fumes. All plastics, some woods (pine), wood products, paints and adhesives. Some exhaust products are more of a concern than others. For example, the formaldehyde leaking from OSB, MDF, chipboard and plywood is perhaps the single greatest hazard in North American homes today. It has long been linked to an increased risk of asthma and cancer. There are none of these wood products in our new, super-insulated house, and our last house, also a wood-processed product, was sold above market value because it was so free from contamination.

Foam sheet releases small amounts of brominated flame retardants and this is a serious problem. Personally, I wouldn't use foam sheets indoors. Nonetheless, flame retardants are just about anything: all upholstery materials, curtains, mattresses, carpets ... I find it even more difficult to remove than formaldehyde. The fact is, most of us are more exposed to danger in our own four walls than outside in our polluted cities.

I am a forest and moisture surveyor. As part of our services, we also insulate houses. To answer the question of whether the PIR insulation can also be a vapor barrier, the answer is "yes", provided that aluminum foil is attached to both surfaces. When you fit this flush between your wood joists, tape the joints between the insulation and the wood stud with aluminum tape to make sure all of the wood is covered. You also need to make sure that the joints between the insulation and the walls, ceiling and floor are sealed.

Owens Corning states that extruded foam board is not a vapor barrier in and of itself as it has a permeability rating of 1.1. Strandboard, for example, has a lower rating of 0.7. Even foam sheets bonded with adhesive tape require a plastic film vapor barrier. Place the barrier on the inside of the house and staple / glue it so that the foam board only gasses outwards. (yes the free styrene - a kind of term for vinylbenzene is exhausted, but not as bad as sprayed foam) - by a construction worker with a strict MCS woman.

Styrene is expected to be human carcinogen based for limited evidence of carcinogenicity from human studies, sufficient evidence of carcinogenicity from animal studies, and supportive data on mechanisms of carcinogenesis. [...]

Polystyrene is used extensively in the manufacture of plastic packaging, thermal insulation in building construction and in refrigeration equipment and disposable cups and containers. Styrene polymers and increasingly also copolymers are used in the manufacture of various household goods, food containers, toys, electrical appliances, automobile body parts, corrosion-resistant tanks and pipes, various types of articles, carpet backing, house paints, computer printer cartridges, insulation materials, parquet waxes and polishes, adhesives, putties, personal care products and other articles, and they are used in paper converting (IARC 2002, Luderer et al. 2005, NLM 2008).

–National Toxicology Program; Report on Carcinogens, 13th Edition (styrene.pdf)

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