How to waterproof a tile bathroom floor?

[Back40]

I would like to waterproof the tile floor in the bathroom of a 50 year old home. This is to prevent any additional waterdamage to the subfloor/floor joists. I tried several applications of sealant product but water still leaks through to the crawl space. I installed a shower door but the tenants seem to be unable to prevent water from getting on the floor when exiting the shower. Are there any other products I can apply.

[rmw]

Are you sure it is water they are tracking out of the shower as that would have to be alot of water to leak through the grout an subfloor into the crawl.

I would look for other sources of water a leaking drain or shower head piping.

[Drywall DIY Guy]

Waterproof Floor

Besides sealing the grout, what we did was make a silicone seal along all top outside edges. So under the floor moulding (which is not wood molding) I put a bead of silicone. Under the vanity I put a bead of silicone. Along the tub too. This will prevent water from getting behind the edges, which is usually the biggest trouble spot. Also, I siliconed under the toilet - I used a waxless ring which allowed me to lift up the toilet 1/8" or so to get a bead of silicone under it.

[LarryHome]

Besides sealing the grout, what we did was make a silicone seal along all top outside edges. So under the floor moulding (which is not wood molding) I put a bead of silicone. Under the vanity I put a bead of silicone. Along the tub too. This will prevent water from getting behind the edges, which is usually the biggest trouble spot. Also, I siliconed under the toilet - I used a waxless ring which allowed me to lift up the toilet 1/8" or so to get a bead of silicone under it.

That's a really neat technique! I'll keep that in mind for the future, thanks.