I need to find out the best way to prime plywood before skimming over. Spoken to British Gypsum but they said they haven’t tested any products for this application - so no comment. The problem appears to be that the plywood will absorb moisture and expand during coating. The wood will then shrink back when dried causing the plaster bond to crack and fail. I have read conflicting reports for using PVA as a primer for this too is water based. Thistle Bond-it was suggested but without any guarantee it will succeed. Anyone got any experience or constructive comments on this application ?
welsh brickie wrote:the only way is to screw wire mesh to the ply,then paint pva on.Once dried use carlite bonding to cover the mesh and thistle multi board laster to skim.
Many thanks for this advice. I have bought a sheet of Metal Lath from B&Q for about £14. Bigger than needed, it cut down very easily to the size of the plywood board - should have worn gloves though! I fixed the Lath with a hand staple gun and not screwed, although not too sure now about the potential for the staples to rust. I have a platerer booked to do the remainder of the work and so, hopefully, job done.