We’re in the process of renovating an old farm house with a old section and a new side.

Because the house has a hydronic heat system we are looking to convert to underfloor heating throughout. Right now it’s a mix of forced air in the old part of the house and underfloor Heating in the new.

We just hit a bump though, having discovered that all the 2nd floor rooms have lead painted floors underneath a plywood subfloor and then a laminate or engineered flooring (depends on the room).

We plan on keeping the old board sealed under a newer floor, but should we look to remove the paint first? Will the underfloor heating cause the paint to off gas or something?


  • 2
    Generally, lead compounds are not volatile. As long as installing underfloor heating doesn't create access to the paint, and does not create dust during installation, it should not be a problem. Check local codes, though. – DrMoishe Pippik Aug 14 '20 at 22:52

Lead melts at 621°F. Fumes are released at 900°F. Your in-floor heating and floor are going to be at temperatures an order of magnitude lower than the temperature you need to create off-gassing.

You should be safe.

  • Why do you assume that the paint contains elemental lead? – DJohnM Aug 15 '20 at 6:54
  • 1
    PbCrO4, and Pb3O4 are the lead states that would most likely be present within the paint. They both have even higher melting/boiling points. I gave the "worst case" scenario and even the "worst-case" is quite acceptable. – ziptron Aug 16 '20 at 1:34

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