Just bought 100 year old house and the second floor walls and ceilings were finished with plywood that was then painted, that is bad looking. i would like to spread drywall mud on the walls and finish it off like a plaster wall, hiding all the cracks and seams. i read where you need to apply a pva primer first to the plywood but it only talked about bare plywood not painted. Can i apply the pva primer over the painted plywood and expect it to bind to the plywood? Thus allowing me to put the drywall mud on.
pva is a penetrating primer, it has very poor characteristics over previously painted surfaces.... instead just look for a primer for previously painted surfaces and if the existing wood is smooth and without areas of flexing or movement...then skim coat away
if not, then please read on.......
you can remove and replace as chrisn suggested
you can just overlay the wood with drywall
drywall has fireproofing characteristic, plus acoustic and insulating properties
they make thin drywall sheets 1/4 inch for overlaying, you should look into it
why do we suggest removal and replacement or overlay with drywall?
without seeing the wood, i myself have pictured the substraight (wood) you have now being uncontrolled. all the countersinking of existing nails and swelling ends of the wood sheets plus splintering or swelling around the nail fasteners them selves...and possible flexing or movement..it would take a very thick layer
of mud to skim over the wood to provide a smooth finish and any continued flexing or movement will cause the skim coat to crack and fail
so under those conditions you ultimately have less mess, less sanding and an overall cleaner look with an overlay or replacement with drywall