Tile over greenboard?

Users who are viewing this thread

Frenchie

Jack of all trades
Messages
1,239
Reaction score
0
Points
36
Location
Brooklyn, NY and Fire Island, NY
I gotta side with Eric, half-way - I've seen drywall-and-mastic last a surprisingly long time.

BUT...what a nasty mess when it does go!

By the time the tiles start falling off, the only thing holding them up is each other, and grout; the few bits of sheetrock that are still there, have turned black with mold (the paper is long gone), and the framing's so rotten you have to replace it.

A lot of unnecessary, and easily avoidable, damage - why risk it?

Make sure you have a gap at the bottom so water won't wick out, Kerdi it - you'll have increased the lifespan, and limited the odds of serious damage later, by a HUGE margin.
 
Last edited:

Southern Man

DIY Hillbilly
Messages
525
Reaction score
0
Points
0
Location
North Carolina
I actually had mushrooms growing out of the edges of a tub in my old house, a 70's rancher. After I cleaned them out once and they grew back, the wife and I opted for full scale demolition. The "tile backer" wasn't even greenboard, but regular drywall. The house was 20 years old at that point, though. Luckily the damage hadn't progressed to the wall studs yet.
 

Jadnashua

Retired Defense Industry Engineer xxx
Messages
32,771
Reaction score
1,191
Points
113
Location
New England
The guts of greenboard is essentially the same as drywall. You end up putting a bunch of holes in the greenboard to install it, and there goes your waterproof top layer. The national codes no longer allow it in wet areas because they realized it isn't a great idea. Go cbu for wet, or drywall for dry (and stay away from mastic where it will be wet!).
 

Southern Man

DIY Hillbilly
Messages
525
Reaction score
0
Points
0
Location
North Carolina
I thought it was heat treated throughout or something. I like it for kitchens above the counter and in bathrooms non-wet areas.
 

Jadnashua

Retired Defense Industry Engineer xxx
Messages
32,771
Reaction score
1,191
Points
113
Location
New England
Greenboard isn't as stiff as drywall and on a ceiling, needs 12" support rather than the 16" regular drywall can handle. The paper is different.

FWIW, the grain of the paper on drywall is such that it is much stronger installed across the studs rather than vertically.
 

JohnfrWhipple

BATHROOM DESIGN & BUILD
Messages
3,225
Reaction score
102
Points
48
Location
North Vancouver, BC
Is Green Board "Green".

"Green" ??? does this "Tag" refer to the colour or it's affect on the planet?

There is a "White" board that is ECO friendly that is called for slang "Green Board" because it is a "Green Building Product" and is not actually Green in colour.

There is "Green Coloured" moisture resistant dry wall (gypsum) products called "Green Board" because they are green and not white in colour. Hmmm.

Now is this not confusing???
 

JohnfrWhipple

BATHROOM DESIGN & BUILD
Messages
3,225
Reaction score
102
Points
48
Location
North Vancouver, BC
Has anyone else worked with this Green EBoard ("Eboard"). I bought my Green EBoard not Green Drywall at Centani Tile and used it for some testing and my daughters shower surround above the tub. The product is about the same price and weight as cement board but a much greener choice.

I takes screws much like cement board but I found the real advantage was in just 60% scoring the lines and snapping the cuts. This speeds up the install a hair and cuts down on dust and noise. The board is stiffer than regular CBU and abroved for use here in North Vancouver (for sure) and all of North America to my knowledge.

I have tried with no success to get a list of cities from their head office but after a month I have no answers.

The jury for me is still out on this product for me and my crew. I like the two options of texture (one smooth and one not) but need to do more testing. I bugs me as well that this information can not be easly obtained and after a few requests I still don't know. But hey - I'm a tough guy to please...

I have a 4 extra sheets and we will offer it to our clients as an ECO friendly product and go from here. Hopefully their Head Office will read this soon and we all can get a list of where to buy this Eco Friendly Board.

Regards,

John Whipple
 
Last edited:

richjsn

New Member
Messages
3
Reaction score
1
Points
0
Location
Saint Charles Missouri
You said tub. Is there a shower in the tub as well or just a tub area? If no shower just tile over the greenboard. If its a shower then you could put hardi over it and use a product called Redguard. Its used almost exclusevly in the midwest. It puts a waterproof coat over everything. Look it up and follow the manufactures recomendations.
 

TWEAK

New Member
Messages
86
Reaction score
0
Points
0
Location
Bay Area CA
If it's a shower, I would definitely not tile over greenboard. There's good reasons why it's no longer approved for that application If it's a tub only, I might... but water tends to wick up from the the tub/greenboard joint so I would worry about that.

Kerdi is great stuff, if a bit expensive. I've heard that it doesn't stick well to greenboard, but I've only used it over regular sheetrock. Call Schluter on that one. Wallboard is so cheap... and in a tub surround there are no electrical boxes to cut out, so changing it out would be a quick job if Schluter says it's not good. With Kerdi, use the Kerdifix sealant or a good polyurethane sealant like P&L to seal the kerdi to the inside lip of the tub.

Redgard is a good product, but it is only a waterproofer if used at the correct dry film thickness. THis takes several heavy coats and they aren't giving Redgard away, either. Laticrete also has a liquid membrane system (I think theirs uses a fabric layer that's puckied in place with the liquid stuff)

Personally I prefer my waterproofing layer on the tile side of the substrate (be it a cementuous backerboard or sheetrock with Redgard). No type of sheetrock, green or otherwise, is impervious to water and neither is backerboard. It all gets soaked. The beauty of Kerdi is that if installed correctly water never gets to anything that's behind the Kerdi. Thus the backerboard and or the wallboard doesn't see any water at all, nothing becomes soaked, and the little water that bleeds in past the grout and/or caulk stops at the Kerdi and drys out relatively quickly. You can get the same effect with Redgard (or Laticrete's waterproofing stuff) so those are good, too, in my book.

Again, if it's just a tub surround (no shower) you might want to take the chance. I had a very bad (=expensive) experience with a slow leak in a tub/shower surround that was tile over Wonderboard over greenboard over 15# felt. The room - all of it - ended up in a 40 foot dumpster. Entire studs were completely gone. So, in my experince, overkilling the waterproofing is cheap insurance.

I don't trust mastic in wet areas, even Type 1. Hard to beat thinset. If you want a stickier thinset, use Versabond or, even stickier, Flexbond, and mix it on the stiff side. You never have to worry about thinset turning to rubber cement.....
 

Jadnashua

Retired Defense Industry Engineer xxx
Messages
32,771
Reaction score
1,191
Points
113
Location
New England
Slightly off topic, but not much!

Even if you end up throwing 1/2 of your thinset away because you mix too much, and it starts to set before you use it, it is likely still cheaper than most mastics...
 

JohnfrWhipple

BATHROOM DESIGN & BUILD
Messages
3,225
Reaction score
102
Points
48
Location
North Vancouver, BC
Q: Can you tile over Green Board?

A: Yes you can - but will your inspector let you? You can tile over just about any surface with the right product. Here in North Vancouver you can not tile over Green Board (the drywall kind) at all in a wet zone. No No No. You can use Green EBoard that is actually white in colour and much like cement board in strength.

If you have all ready installed this Green Board and do not have the funds to upgrade to a better system at the very least apply a couple of coats of Hydro Ban or Redguard. I have asked if this is OK of my inspectors and they said it's not OK and that they would fail - but if you are just going to leave it anyway at least it is one step towards extending the life of the job.

And if you are not prepared to spend the $70 - $100 for liquid waterproofing then at the very least skim the walls out with your mastic (I assume Mastic as 1 in 2 "Box" store employees in my research suggest Green Dry Wall and Mastic) first and let dry and set the following day.

I am not endorsing any of these installs as I know the lifespan to be too short. I am pointing out the steps to improve a system all ready started and have found many people unwilling to change their work so late in the game. And if most of North America and half of the "Flooring Experts" recommended it why would I listen to these online ya hoos....

Do some more research - check with city hall - understand the life span of your install and do what's right for your family, the environment and our land fills. There is to many bathrooms in our land fills and most of them I would guess have started out down this similar path.

I my opinion green drywall is "Crap" and has not place in your shower or wet zone.

My thoughts....

But what do I know?...

I only do this everyday for a living...

JW
 
Last edited:
Top
Hey, wait a minute.

This is awkward, but...

It looks like you're using an ad blocker. We get it, but (1) terrylove.com can't live without ads, and (2) ad blockers can cause issues with videos and comments. If you'd like to support the site, please allow ads.

If any particular ad is your REASON for blocking ads, please let us know. We might be able to do something about it. Thanks.
I've Disabled AdBlock    No Thanks