Do i need to strip years of brown varnish off the interior doors before painting them white.?
Anything that has been varnished ought to only receive more of the same. This is because if it was done properly in the first place, the first coat of varnish would have been thinned out to soak deep into the wood. As a result the wood is sealed against future wood primers taking a grip, even after stripping and therefore always will be prone to chipping. DIYers and uneducated painters still paint them with varying degrees of getting away with it, depending on how well it was varnished in the first place. If you insist on painting it, ideally you strip it all back and reprime, if not, then rub every square centimetre to provide a key and go straight on with an oil-based undercoat. Primer would be pointless if you are not stripping it.
