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Intumescent Paint Health Concerns?

sb1616ne | Posted in General Questions on

We have closed cell foam installed as part of a big renovation project for a few basement spaces. Some areas will be covered with drywall and others with intumescent(fire retarding) paint. We can drywall more areas if needed, but painting is the easiest option. The spray foam contractor would be using this DC315 paint. Are there any obvious concerns about toxicity of these coatings? I cannot find much either way, but it cannot be any worse than the closed cell foam?


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  1. jberks | | #1

    In my personal opinion, you're better off drywalling, from a fire protection standpoint and aesthetics.

    Intumescent paints are fine and dandy, other than the volatilization of halogens when its actually in a fire. However, nothing beats the endothermic properties of gypsum.


  2. Expert Member
    BILL WICHERS | | #2

    Most of those materials are pretty stable after they've cured. You don't really want to be around during the installation breathing fumes though, but that's the same issue with polyiso too. The biggest issue I have with a lot of fireresistant coatings is that many tend to be crumbly and dusty. I've had a lot of that stuff in my hair lately, and clothes, and all over me, since I've been working in a commercial building that uses the stuff on the steel frame of the structure (note that while the building I'm in right now uses white/gray stuff, there is also a blue version that we like to call "smurf barf" :-).

    I wouldn't worry about what that stuff does in a fire, since it's only purpose in a fire is to buy you some time to get out of the burning structure. At that point, the fire itself is the bigger concern in regards to your health, for obvious reasons!

    Drywall does have some advantages, and I also trust it more than the coatings (especially the paints -- I want to see something with some thickness, the commercial stuff used on steel is usually at least about 1/2" thick, for example). Drywall is more labor to install though.


  3. sayn3ver | | #3

    I'm an electrician and not an expert regarding intumescent coatings. But we use intumescent caulks, pads, putty, etc for fire rated assemblies in commercial projects per spec.

    Call me old school, but if possible, I'd rather have a thick physical barrier over foam than intumescent paint.

    Construction can be dogmatic, opinionated, etc with older tradesmen preferring traditional methods and younger guys preferring the next great thing.

    Im mid 30's myself. I personally feel intumescent paints are a way to meet a building code in a last resort sort of way. I'm not saying they don't work. Like many products, methods and details that are coming to market, just because you can do it doesn't necessarily mean you should or at least, doesn't necessarily mean you should opt for them to be your first option.

    As mentioned above, on commercial projects you typically see a variety of 5/8" firecode single layer details, then double layer 5/8" details. Then you'll see elevator shafts and occasionally stairwells get 1 1/4" shaft liner with possibly a single or double layer wall on the occupied side.

    Modern homes and structures are all filled with tons of highly combustible engineered woods, finishes, etc. those with roof or floor trusses or i joists will all burn hotter and faster than a more traditionally framed home. A layer of drywall is just buying you a smidge more time to get out before foam ignites and starts gassing.

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