City of Palo Alto rejects any drywall in wet areas - suggestions for backing?

**tom12** · 03-21-2012, 10:13 AM

The Building Dept of Palo Alto rejects the use of green or any other drywall in wet areas. To achieve a S&C floated surface for tile, what other backing suggestions would you recommend? Perhaps a Two-Coat float over mesh and 15 lb felt?

**cacher_chick** · 03-21-2012, 03:02 PM

Everyone in the country is using cement board, or some variation of it.
It's been this way for a quite a few years now.

**jadnashua** · 03-21-2012, 04:39 PM

They seem to be oblivious that if a waterPROOF surface membrane is applied properly, the drywall is NOT in a wet area. But, trying to talk sense into some people is useless. The only thing I'd consider is to show them the TCNA method approval that allows it. But, as said, it's based on a proper install. You do what you have to, so cbu, while harder and more expensive, is usable underneath any of the surface membrane materials, either painted on or those in sheets. Note, not all sheet membranes support drywall - the TCNA procedure references the manufacturer's recommendations. Kerdi, for one, prefers this, but is equally viable over other backing materials to meet local ammendments to the TCNA procedure. I guess the thousands of installs that are in great shape has no credence...fighting city hall is possible, but sometimes not worth the effort when a viable alternative is available.

**dlarrivee** · 03-21-2012, 05:35 PM

Jim we both know that people expect to hang board and tile right over it, I'm sure that is why the county is not allowing it.

What about fibreglass faced gypsum board?

**jadnashua** · 03-21-2012, 06:21 PM

Seams where it's been cut are still problematic unless it's properly waterproofed. guess you just have to ask them what they'll allow.

**dlarrivee** · 03-21-2012, 06:22 PM

Originally Posted by jadnashua

Seams where it's been cut are still problematic unless it's properly waterproofed. guess you just have to ask them what they'll allow.

Problematic how?

You could use fibreglass faced drywall everywhere in a bathroom, waterproof the wet areas, and skim coat the rest.

**jadnashua** · 03-21-2012, 09:02 PM

While fiberglass may not be mold food, if you get gypsum wet, it can turn to mush, so any seam has the potential of being a problem...depends on how well you put things together, but it's not cbu which doesn't really care if it gets wet.

**jimbo** · 03-22-2012, 06:25 AM

If by wet area you mean the shower, it has not been approved for 20 years to use any kind of drywall under tile. It MOIST areas, like the walls and ceilings in a bathroom, they came out with the "greenboard" but it really was not the answer. They do now have blueboard, which does not support mold growth, but it is not water resistant. Use cement board, or actual lath and mortar, under tile in showers and on the floor.

**johnfrwhipple** · 03-22-2012, 06:37 AM

Originally Posted by tom12

The Building Dept of Palo Alto rejects the use of green or any other drywall in wet areas. To achieve a S&C floated surface for tile, what other backing suggestions would you recommend? Perhaps a Two-Coat float over mesh and 15 lb felt?

The best backer board in the industry right now (my opinion) is Green EBoard. Take a look at it.

Green EBoard

This board meets all industry standards and more. Bug resistant. Water resistant. Fire resistant. And you can hang it like you do drywall with a razor blade and drywall saw.

No grinder.

No Hardie Blade.

So easy to use and install. These past 18 months we have used it on 80 percent of our projects. I used it in my daughters bathroom.

The backer board also accepts drywall compound so your mudders can skim it and tap it like regular drywall.

When picking a backer board this Green EBoard is a no brainer. If there is a better product out there - I havn't seen it.

JW

**dlarrivee** · 03-22-2012, 05:05 PM

Be careful, if I didn't know any better I would say that John makes more money promoting products on the internet than he does remodeling bathrooms.

**johnfrwhipple** · 03-22-2012, 07:04 PM

Originally Posted by dlarrivee

Be careful, if I didn't know any better I would say that John makes more money promoting products on the internet than he does remodeling bathrooms.

That's funny.

Have you tried Green EBoard? Once you have you will be recommending it as well!

JW

**dlarrivee** · 03-22-2012, 07:19 PM

Are you related to Billy Mays?

**johnfrwhipple** · 03-23-2012, 05:37 AM

Who is Billy Mays? I'm related to a Billy (Bill) Buck - but no Mays in our family.

Some how I feel if I goggle the name I'm going to see a dude with a infomercial.

**tom12** · 03-23-2012, 10:27 AM

Thanks for your replies, but i'm not much further ahead. I'm looking for a sound method of floating given the above conditions. Backer board is obviously not the answer.

AAMOI, San Jose bldg dept were passing shower walls with drywall behind a floated coat up to 2001, as far as i recall.

**ballvalve** · 03-23-2012, 11:08 AM

Heres the stuff. I have a unit of 'secure-rock', and use it for plenums and baths. Its made for roofs, an older version and a sheet of 5/8 weighs over 100#. http://www.usg.com/durock-cement-board.html