I am in the process of re-doing the bathroom and intend to install tile over waterproofed cement board. Have an acrylic tub as well. However, there is a window in the enclosure equipped with the standard 3/4″ jamb extension slot. Have to ensure a good waterproof joint between the window and tile. Any thoughts on tile installation, i.e. will thinset adhere to the vinyl {using “Megalite” thinset}. or will I need silicone here. The ledge will only be about 2″ wide and needs to slope a bit.
thanks…Bill
Replies
Wow -- so many thoughts.......
If the window is in a tub alcove, that's one thing. If it's a tub/shower enclosure, that's a huge difference. (Although I don't like either idea, really.)
You asked for thoughts about a waterproof joint to the vinyl window.
IMO, the waterproofing should come from a sheet-barrier of some sort. I really like the idea of Kerdi, siliconed to the window jamb, and extending down to the tub lip. (Remember, grout, thinset, and backerboard are water shedding -- not waterproof.)
(Thinset might initially adhere to vinyl, but the different ranges of expansion and contraction are a big problem.)
But even that doesn't solve all of the problems. Windows are only designed to be waterproof from one side -- the outside. Water that hits the jamb will wick between the jamb and the sash. It will eventually get into the screw holes that mount the window. And then you'll have rotted framing.
And as you mentioned, the ledge will trap water and send it under the sash. Depending on the design of the window, that's a potential problem too.
And just one more thought -- some vinyl windows (small percentage probably) are manufactured with wood pieces for added strength. Although they can't be seen (they're wrapped in vinyl), they can still rot if water gets to them.
I won't be laughing at the lies when I'm gone,
And I can't question how or when or why when I'm gone;
I can't live proud enough to die when I'm gone,
So I guess I'll have to do it while I'm here. (Phil Ochs)
The cement backer board has 3 coats of a barrier product called RedGard..like a roll on rubber. Stinks like heck but seems to provide a good barrier. A narrow piece of cement board goes into the jamb extension slot and the joint between it and the main board is well coated with the barrier as well.I had not considered the expansion differences but now that I think about it, you are correct. And yes the window is in the tub/shower. I agree not the best and had I built the place it would not be there.What I am thinking now is to use a good silicon to adhere the 2" strips that will be over the window jamb extension and meet at 90 degrees to the main tile. A strip of Kerdi to bridge the two would also be a thought.thanks..Bill
RedGard is good stuff, eliminating the need for kerdi on the wall.Using a silicone to adhere tile to the vinyl -- two thoughts:1. Just an opinion, but RTV-style silicones are quite impressive.2. I might not use silicone as the adhesive for ceramic -- I'd want to use a urethane sealant. But of course, I'd need to check with the window manufacturer concerning the use of urethane on vinyl. Urethanes set up to be almost like tire rubber. And of course, once you've got it all in place, use the color-matched caulk to match the grout.
I won't be laughing at the lies when I'm gone,
And I can't question how or when or why when I'm gone;
I can't live proud enough to die when I'm gone,
So I guess I'll have to do it while I'm here. (Phil Ochs)
Make your extension jambs and casing from Azek or similair.
Butt your tile to it with proper details.
"When the spirits are low, when the day appears dark, when work becomes monotonous, when hope hardly seems worth having, just mount a bicycle and go out for a spin down the road, without thought on anything but the ride you are taking." — Sherlock Holmes, 1896