I used green board on my bathroom ceiling and will be using cement backer board around the tub….I’m not sure how I would blend in the two different types of boards along the ceiling. Should I use fiberglass tape, then apply mastic and sand?
Thanks,
Sandra
In certain scenarios, flat roofs make more sense than pitched roofs (and vice versa).
"I have learned so much thanks to the searchable articles on the FHB website. I can confidently say that I expect to be a life-long subscriber." - M.K.
Dig into cutting-edge approaches and decades of proven solutions with total access to our experts and tradespeople.
Start Free Trial NowGet instant access to the latest developments in green building, research, and reports from the field.
Start Free Trial Now
Replies
Greenboard is a no no for ceilings here in SoCal. But to answer your question tile up to the ceiling grout tile and use a color matched caulk at the ceiling tile junction.
Bing
Bing,
Just so I understand....I don't have to tape the ceiling edge at all?Thanks,
Sandra
you still have to tape the ceiling with fiberglass tape n mud....then run your tile to the ceiling and caulk all inside corners with color matched grout/caulk. The good tile/grout caulk ain't cheap either. Around ten+ bucks a tube or the cheap stuff from HD for about $6 ish I thinkView Image
The Woodshed Tavern Backroom
The Topics Too Hot For Taunton's Breaktime Forum Tavern
Andy,
It's o.k. to put joint compound on the cement board, then tile over it (just at the ceiling)? Sandra
Normally I use thinset to tape all my joints on the cement boards but if I'm transitioning from a cement board to drywall I'll use joint compound. If you're tiling the ceiling and using backer board up there then use thinset. Makes no sense to use drywall compound on cement boards. Makes sense to use cement on cement especially in the field where your main tiles are going v.s the outer edge where it'd just get painted.View Image
The Woodshed Tavern Backroom
The Topics Too Hot For Taunton's Breaktime Forum Tavern
Thanks Andy
I used a setting type compound on my cement board to dw ceiling corners, on advice from the group here.
It allows you to finish the drywall ceiling in the normal manner and the single run of setting compound doesn't affect the thinset and tile install on the wall. Worke great for the ceiling that was not tiled.
I use setting compound for drywall also such as the blue board over tubs and showers but any ceiling that'r cement board I use thinset excet where it transisions to the drywall where I use compound.
When I'm using thinset on my cbu wall seams...when I get to the top...if it's blue-board at the ceiling I still use thinset just because it's already in my hand. I count that as my first coat of mud. ...then I use 2 coats more of joint compound over the ceiling inside corner thinset.View Image
The Woodshed Tavern Backroom
The Topics Too Hot For Taunton's Breaktime Forum Tavern
The problem with regular premixed joint compound is that water disolves it - you need trust that it will never get wet - maybe an acceptable risk at the ceiling, but that vertical joint on a wall would scare me.
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
We use paper tape and hot mud ( Durabond) for taping between SR and the Cement board. Mesh tape on the CMbd
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
Thanks Piffin....Sandra
What is the reason you can't use green board on the ceiling. What do you use out in So. Cal?
It's probably bee known to cause Cancer in California, LOLActually, even tho greenboard is moisture resistant, it seems to be more prone to sag on ceilings for some reason. I've never had the problem, but we frame 16" OC
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
Yeah. 16" o.c. is the magic number.
There is not more "regular greenboard". The greenboard you see now is mold resistant and made by USG..different from the old greenboard and can be used on ceilings 16" oc while previous it was 12" oc.
it's been about 1-1/2 years since I bought any, so didn't know that.
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
We use type x. 1/2 or 5/8. Green board just doesnt have the structural integrity. So the inspectors insist on the type x.Bing
If you are not tiling the ceiling then just tape with paper tape compound and forget about it .
Straight Flex and hot mud.
The awful thing is that beauty is mysterious as well as terrible. God and the devil are fighting there, and the battlefield is the heart of man.
- Fyodor Dostoyevski
Not to be picky but in your original post you used the word "mastic".
At no time should the pre mixed mastic be used in a wet area. The stuff will retain water and mold will form under your tiles.
Use thinset mortar. and look into using a membrain such as Schluter Kurdi.
the membrain is not required with your cement board but it adds to the protection of your wall. I highly recommend it.
Thanks Jet....Sandra
Good point on the 'mastic' as a no-no in wet areas. I think it is spelt Kerdi
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
"I think it is spelt Kerdi"
What are you, a membrain?
I thought they called me a squid 'cause I was an oxymoron!
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
Congratulations!
fingersandtoes receives the 'MrT/brownbagg OneLiner Award'.
Saaalute!!!View Image View Image
Thanks. I have longed for a dancing baby for ages but was too shy to ask.
Be thou carefull.If that babies diaper falls off, you'll go down for child ####.I can't say whether you'll get kicked off BT or not
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!