Thread: Furring studs
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Unread 01-14-2021, 07:37 PM   #8
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Join Date: Jul 2001
Location: Boerne, Texas
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Dave, it'll help if you'll keep all your project questions on one thread so folks can see what you're working on and what's been previously asked and answered. A moderator can give it a more generic title any time you'd like to suggest one.

There are only two direct bonded waterproofing membranes (ANSI A118.10) out there that are approved for use over gypsum drywall in a wet area and neither of them are liquid applied. And even with those we'd recommend plain white drywall and not MR board (greenboard, etc). In fact, best to pretend you've never heard of greenboard nor any application for which it is necessary on accounta there really aren't any. Well, actually the only potential reason it could be necessary is if an out of date code compliance inspector wants to see it in some particular are of your bathroom.

You can cut a CBU with various saws and grinders, but it's a very dusty process and best done outdoors in a good breeze. Some you can score and snap fairly easily and cleanly, but for narrow strips I'd recommend the saw.

And yes, if you wanna use those liquid applied membrane you must first install a CBU and treat all the joints and seams per manufacturer's instructions before waterproofing.

My opinion; worth price charged.

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