Houston, I have to agree with the others re: the t&g from a bad personal experience, where I was asked by my customer to tile onto t&g which I screwed really tight. The issue was height, because the front door was a pvc one and couldn't be trimmed at the bottom to accomodate any extra height that overboarding would cause, so I advised it best not to tile at all, but they were insistent, and, instead of walking away I gave in. Having done the job, I was waiting for the phone call, and sure enough in 3 months time - "can you replace 6 tiles that have cracked please" I got paid for it, but I was really uncomfortable doing this knowing that it would probably go again, which it did, but on the upside I could have been employed there full time replacing them when they went:lol:, but you just can't say told you so. The moral of the story is that I would NEVER do this again for anyone, I'd rather walk away from it in future. I have to say I think you have been lucky so far, I only did it the once. But we will all do things differently, that's what makes us human.