by chris_on_tour2002 »
Mon Nov 24, 2008 11:15 pm
firstly you need to try to establish what is causing the stain. could it be damp? if so, you need to investigate to establish the cause and then remedy before tackling the stain.
if it is benign then a stain block is all that's needed. try a primer by the name of bullseye (made by a firm called 'zinsser') which has excellent stain blocking properties. if that doesn't work then try a damp seal such as aquaseal.
pva will probably not work very well as a stain block depending on the type of stain that it is.