I'm in the middle of a residential new construction project, targeting Passive House requirements. It is an insulated slab on grade, double-wall stick built home, where the air barrier is on the outside/exterior wall. There is no vapor barrier, and there is an approx 20" cavity for dense-pack cellulose. We just finished air-sealing, and my builder coated the top of the concrete slab in between the double walls (20" of concrete) with 10 gallons of Henry's foundation coating. Of course, this is an exterior-grade product that contains tar and a lot of nasty VOC's. I wasn't happy at all when I learned they had done this. My question is, is there anything I can do to help indoor air quality once the product has "cured" and is done with its initial off-gassing? My plan was to have them let it cure as long as possible before blowing in the insulation. But should I have them also top-coat it with something that would seal-in the nasty VOC's? I'll have an ERV always running to help with ventilation, but I don't like the idea of having tar in my walls. Any advice would be appreciated. Eric

one: find a new builder! This guy has no clue about building tight houses, so my guess is that you'll have other issues that you won't see or smell until the house is complete.
I'd strongly encourage you to stop the project until this is removed, or you will be smelling and ingesting volatile chemicals for years and years and years.
We did coat a foundation exterior once where some of the tar would have been exposed. We found that after scraping what we could, we sandblasted the wall and that removed the rest. Whether this will remove whatever chemicals have penetrated the concrete is anyone's guess. Do not assume that covering it with something will solve the problem. It won't and will be far more expensive to remove after the house is done.

Thanks much. The builder is going to fix. Much appreciated.