Looking for a non-toxic under-slab insulation
I’ve designed my building to avoid many unsavory products, but I’m stuck on this one. I’m more concerned about toxic, bio-accumulative, and environmentally persistent toxins as opposed to the global warming potential of chemicals.
It seems that I have a choice between the hbcd flame retardants in polystyrene, polyisocyanurates, or formaldehydes in rock products like DrainBoard. I could alter my plans to accommodate Perlite, but I’m not sure it’s worth it, assuming a high embodied energy, and the associated byproducts of fossil fuel combustion used in the popping process.
Polystyrene should be a relatively benign product without the flame retardants? Does anyone know of a polystyrene product without such additives? I’m not worried about fire under my slab.
I’m open to all suggestions.
I may have to redesign how my building contacts the ground in order to avoid such chemicals…but hope I don’t have to go that route.
Thanks,
-Richard
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Replies
foamglas? same issues as perlite - high embodied energy. if i recall correctly, it's benign and doesn't have any toxins. tried to use on a project but was VE'd out over EPS.
GWP = 1, ODP = 0.
the amount of formaldehydes in rock wool is fairly insignificant in the end product; IIRC it is barely detectable
unless your building on the galapagos islands, it shouldn't be an issue
Richard,
If you really want a no-foam house, I think you're stuck with a house on piers or a house on a ventilated crawl space. If you live in a cold climate, however, it's going to be tough to keep your plumbing pipes from freezing without the use of heat tape.
Thanks for the advice guys... I'm going to open a new question regarding the detailing of an uninsulated floor.
Expanded Polystyrene used as an under slab insulation does not have to be fire retardant in most jurisdiction's. Thus you can order "Non-modified" EPS that will meet your needs for a product that will maintain its R-Value for life and not leech anything into the ground.
Steve - I can't find a non-modified EPS without the brominated flame retardants... do you have a source?
The local building supplies can't help me.
The one manufacturer (Plasti-Fab) I spoke to said that it may be impossible to find a foam board meant for construction which does not contain the chemicals...due to the multi-purpose above & below grade usage of their foam.
Owens Corning, DOW Styrofoam, and Johns Manville are the big names here in Southern Ontario, I've dug through their websites and found nothing.