In a new bathroom that we are installing, the drywall guys put up durarock around the tub area.
The helper for the drywaller taped the corners of the durarock with regular joint compound.
I was able to pull off most of the tape, but my question is can we just run thinset mortar over this or do i need to remove all the joint compound (it’s embedded in the irregularities of the durarock and extends out from the corners about 4 inches.
]Needless to say, the helper never came back after that screwup.
Thanks.
Dave
Replies
Not a tile specialist but I wouldn't sweat it. I usually overlap my tile past the druock onto the gypsum wall board for looks anyway. As long as there isn't excessive mud. Hopefully the durock is screwed down.
Let's not confuse the issue with facts!
This was on the inside corners where durarock meets durarock (where the long wall of thw tub surround meets the 2 shorter walls at the ends of the tub).
Yes, it was screwed but I think with regular drywall screws, which I will replace with cement board screws.
Not to worry.Show me a guy my age with an open mind,
And I'll show you a guy with a hole in his head.
- Me
So, Mike, should I just leave the compound in the corners and put thinset over it? Won't it break down when it gets wet?
I assume some moisture will get through the thinset.
Thanks.
Dave
Yeah, get rid of the compound. Wet compound will melt and your tile will fall off. Scrape it off with a paint scraper to the point that your thinset will contact only the cement board.
Yep, you're gonna have to wash that spackle off. Warm water, a little waiting while it softens, and working it over with a stiff scrub brush oughta do it once you scrape it flush with the dimpling on the cement board.Dinosaur
'Y-a-tu de la justice dans ce maudit monde?
Yep.. get rid of anything that may contibute to a failure. Cheaper to do it now than to have to repair it later.
Okay, I scraped it down and dug out the compound from the corners. I will now scrub it with warm water to get off the rest of the residue.
The other thing that I noticed is that in the corners, where there is like a 1/4" space, you can see the studs behind the cment board (it is actually Permabase). The Permabase has a shiny coating to it. Does this mean it is waterproof and can be applied directly to the studs? I thought I had read somewhere that felt paper should be put on the studs before applying the cementboard.
TECHNICALLY... no, according to their web "advice" http://www.nationalgypsum.com/resources/faqs/permabase.html. I would, however. Since you are replacing the screws anyway... just go ahead and drop the stuff out and install the VB.
One thing though.. are you tiling this, or just putting up a surround? If you are tiling... this particular product isn't necessarily suited for tile backer on vertical surfaces(refer to same page).
Is the cement board the same on both sides? If so, and you pull it to put in a vapor barrier, the symmetrical pieces could be re-installed flipped, so the other side is out. That way you don't have to worry about cleaning the mud off of any but the asymmetrical ones. I'd think a real stiff scrub brush, or even a wire brush....
-- J.S.
You definately want a vapor barirer behind your cement board even if there is rock behind the cement board.You definately need to use a galvanized screw to attatch it.Most specs. for this type of assembly call for corners and seams to be taped with mesh and thinset.