Question
How do you deal with existing, possibly toxic, wall and floor finishes?
I have read so much about green paints and finishes, but nothing about how to remove or encapsulate the non-green paint or finish that is already in place. Do you simply paint over old interior paint with a green product, or do you have to scrape off the VOC stuff first? Likewise, how do you deal with a toxic finish like that on hardwood floors?
Answer
For walls and ceilings, it depends on the original type of paint.
Flat latex paint can be painted over with green paint without a primer. However, if the original paint is still offgassing, it will keep offgassing through the green paint.
If the existing paint is semi-gloss, gloss, and/or oil base, you'll need to sand it lightly and apply a primer. If you suspect that the original paint contains lead, do not sand it. Lead paint is poisonous. Homes built before 1978 are likely to have surfaces coated with lead-based paint. Consult the EPA's publication Renovate Right (PDF - download) for detailed advice on handling lead paints.
If the paint is not peeling or chipping, wash it with a mild green cleanser and paint it with a primer, such as Zinsser B-I-N Primer, a non-breathable coating that seals in old finishes and the gases they give off. This product has a very strong odor just after applying, but it offgasses quickly. Read more about proper application of B-I-N Primer here.
Refinishing hardwood floors is tough, since many green floor coatings will not adhere to the old polyurethane floor finishes that are probably on your floor now. Sanding may be your best bet. If you decide to sand, the floor must be sanded to bare wood before you apply a new green finish. Use the tips and precautions outlined here to minimize the risk of inhaling toxic dust.
