Problem Solving Forum
March 16 - March 20, 2015
How do you determine whether a lead-bearing coating can be overcoated or removed and replaced?
Don Wilson of Boral building products on
March 27, 2015:
If it is sound and solid with no signs of peeling, ...read more If it is sound and solid with no signs of peeling, you can overcoat it.
Warren Brand of Chicago Corrosion Group on
March 20, 2015:
The answer is twofold. First, of course, is adhesi ...read more The answer is twofold. First, of course, is adhesion. But the fact that the lead based paint (LBP) is still there is already a good indication. Second is the type of paint you want to apply. New paint may, or may not, impart surface tension on the material beneath it. You'd have to conduct adhesion testing on the LPB and make a determination if it was well-enough adhered to be overcoated, and you would have to ensure that the new paint would not impart enough surface tension to cause the LBP to disbond from the substrate or cause a cohesive failure within the LBP. The other problem is that, sometimes, people will test adhesion before surface prep. This is a mistake. If you're going to conduct some type of surface prep to the LBP, like a water blast, be sure to conduct adhesion testing after the water blast, or whatever surface prep you're going to do, to ensure that the surface prep has not somehow degraded the LBP's adhesion.