I have a 1921 home. Guaranteed that the walls have lead paint somewhere beneath, right? All surfaces have been painted at least once if not 2 or 3 times since 2001. The paint is all in good condition – no chipping. To my understanding, this is good encapsulation.
If we had someone do a lead survey with the xray gun, would these surfaces test positive for stuff beneath? Or does the gun ONLY test the surface layer?
I'm curious to know for sure that my surfaces are safe, but due to mandatory reporting/remediation, I don't want to risk testing positive from a sensitive instrument that picks up a signal from a very low risk and covered up surface.
Best Answer
The short answer is Yes, X-ray lead paint detectors can 'see' lead through top layers of non-lead paint.
But it depends to some degree on the thickness of the layers of paint as well as the type of X-ray detector 'gun' used.
There are 2 types used for lead detection: K X-rays and L X-rays.
The K X-rays have higher energy than the L, which means that they are less attenuated by layers of paint.
So a K X-ray lead detector will be better able to detect lead in lower layers of paint than an L X-ray detector.
If you're concerned that you might get a positive reading from an X-ray lead detector, then you'd probably be better off having a chemical lead test done instead, since this should only be able to find lead in the surface paint layer.