plywood damaged by water - DIY Chatroom

hendjl · 11-02-2009, 04:08 PM

I have a 6" step into my shower. It was made with framing lumber, then a foil backed plywood covering the lumber, then concrete board over the 1/2" plywood, Then tiled and a shower door installed. The two walls of the step are splitting apart from the top of the step allowing water to enter through the cracks in the grout. I suspect the plywood got wet and expanded. The tile is not cracked, only the grout.

Is there a product to inject into the plywood through the cracks in the grout that would keep the plywood from expanding further thus preserving the tile work?

If there is not, then I suspect i will have to take off the shower door, tear out the tile on the step, take off the damaged plywood. What is the product to replace it with to assure this does not happen again?

Ron6519 · 11-02-2009, 09:23 PM

There is no magic substance that will counteract water intrusion. You will need to open the area up and replace the damaged wood. There will be more damage than is evident. Don't be surprised if you need to replace the entire base.
As an alternative to a wood curb, look into Schulter and the curb they sell. The difficult part is integrating and waterproofing one aspect of a system.
Ron

RobQuillin · 11-02-2009, 09:38 PM

If the Schleuder system isn't what you are looking for there is a product called Red Guard that you paint onto your surface before tiling. The Red Guard dries into a ruberized membrane. It works pretty good when you are having to do repairs and want to make sure that you have the subsurface sealed tight.

hendjl · 11-03-2009, 12:39 AM

Thank you both.

ccarlisle · 11-03-2009, 08:47 AM

I'd say you have one of countless millions of showers made in the past 50 years (and that are still being made that way) that experience the same problem. In essence they are made to fail within a short time; it is only recently that people have come to understand that there are solutions to it that don't cost the earth to implement.

It is said that the average shower walls and floors receive more water on them per unit area than than your roof does - and I believe it. Ultimately, you will have to waterproof the whole shower stall in order to put future mould problems to rest.