Greenboard - partial vs full bath

17587 Views 38 Replies 16 Participants Last post by blacktop, Oct 25, 2017

artinall

Discussion Starter · Mar 27, 2017

So many baths I see over the years have been done in typical 1/2".

I've done greenboard immediately surrounding the tub/shower area, and, with another bath ahead now to drywall -- does it really pay to do the full bath in moisture-resistant board? (for paint grade finish, no tile on walls)

I've always used the green - is the purple much different or easier to work?

Might as well review my taping too: I normally use paper tape (or Fibafuse tape, not mesh) with lightweight multipurpose to bed it. I've heard of the term "moisture resistant mudd" being tossed around, but my take on this is that drywallers are simply using setting-type compound OR straight mudd with topping with this description. I've never set eyes on "moisture resistant' compound ...

The room is in the basement with an electric air vent added...

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Tinstaafl

· #2 · Mar 27, 2017

Can't find greenboard around here any more--just the purple. I don't really see any difference as far as working with the stuff.

If you have good moisture removal (read: fan on a timer), IMO you'd be fine with regular drywall throughout. Doing the whole deal in green or purple would be overkill.

Never had a problem just using all-purpose mud.

Reactions: 2

Golden view

· #3 · Mar 27, 2017

The fan and timer is much more important than the drywall.

Framer53

· #4 · Mar 27, 2017

I think I pay a dollar a sheet(4x8)more for the purple drywall.
Why both with trying to say a few when you know it is a better application to use the water resistant drywall?

Reactions: 1

philcav7

· #5 · Mar 27, 2017

I stopped using MR/Barney board in bathrooms. Locally, it's about 40% more than regular board...not that an extra few bucks is a big deal, but I don't really see a point in it. If it gets wet, it still fails. It doesn't paint as well. Properly sized fans pull excess moisture adequately. Showers we build are almost always tile surrounds.

I do use MR in basements as these locations are subject to higher and more continuous moisture and less ventilation.

John1957

· #6 · Mar 27, 2017

I pay the few extra bucks and go with mold resistant, but I have done many tear out's where regular rock was in place and didn't see any mold issues.

Most of the mold that I come across in bathrooms is from poor ventilation ducting dripping onto ceilings and walls, and I see it much more in the fairly modern condo type units than I do in stand alone houses.

Most of the mold that I see in stand alone houses is from neglect by the homeowner who doesn't keep up with maintenance.

(caulking around the tubs and showers, bad tub and shower plumbing behind walls and under kitchen sinks)

SLSTech

· #7 · Mar 27, 2017

Green is pretty worthless - the paint & using a timer deals with normal usage (assuming the vent, vents outside)
If you are worried about moisture I would go with a densarmor & not use paper tape

artinall

Discussion Starter · #8 · Mar 28, 2017

Framer53 said:
I think I pay a dollar a sheet(4x8)more for the purple drywall.
Why both with trying to say a few when you know it is a better application to use the water resistant drywall?

Because it is harder to work with.

John1957

· #9 · Mar 28, 2017

artinall said:
Because it is harder to work with.

Why is it harder? What problems have you ran into? I have no problems with the newer mold resistant rock. It appears to cut and snap as good as any other. I have more issues with the USG lightweight boards than any of the mold resistant. USG was supposed to have taken care of the problems with the lightweight board, but I still run into air pockets and hard spots.

Gold Bond XP mold resistant (blue board) is very easy to work with. It cuts and snaps pretty nice with minimal rasping.

artinall

Discussion Starter · #10 · Mar 28, 2017

John1957 said:
Why is it harder? What problems have you ran into? I have no problems with the newer mold resistant rock. It appears to cut and snap as good as any other. I have more issues with the USG lightweight boards than any of the mold resistant. USG was supposed to have taken care of the problems with the lightweight board, but I still run into air pockets and hard spots.

Gold Bond XP mold resistant (blue board) is very easy to work with. It cuts and snaps pretty nice with minimal rasping.

My experience is that it is harder to cut, more brittle, and heavier to boot.

blacktop

· #11 · Apr 5, 2017

artinall said:
My experience is that it is harder to cut, more brittle, and heavier to boot.

Oh you poor thang!

Framer53

· #12 · Apr 5, 2017

artinall said:
My experience is that it is harder to cut, more brittle, and heavier to boot.

Huh?
Your experience is not the norm, for sure.

artinall

Discussion Starter · #13 · Apr 6, 2017 (Edited)

Okay, I guess greenboard could have only seemed heavier...

Framer53 said:
Huh?
Your experience is not the norm, for sure.

You don't notice it being more difficult to cut?

Blacktop: maybe you have some green to contend with in the a.m.? You're trying to psyche it out? ... But I see you agree and that's good enough!

artinall

Discussion Starter · #14 · Jul 23, 2017

I've searched and there are no stores around here that have 1/2 inch purple (they'd have to order a stack).

With 1/2" green needing 12" joist spans (ours are 16" on center) -- would the 1/2" even suffice for the ceiling? Isn't the 1/2 purple less resistant to bowing than the green?

Since the 1/2" purple is supposed to be fireproof - do you really need 5/8 on the ceiling?

Only other option I can find now is to use 5/8 purple (the only purple around) on ceiling and 1/2 green on walls.

Framer53

· #15 · Jul 23, 2017

First, 1/2" rock is good for 16 centers.
Second purple is green just a different manufacturer.
As far as fireproof all rock has a 20 minute rating. Purple is not different. They do not use paper that will become moldy.

EthanB

· #16 · Jul 23, 2017

All of them will grow mold. We see it on a weekly, if not daily basis. Mold resistant means little when an actual leak is present. I'm of the belief that in most situations, regular board is fine as long as waterproofing and ventilation are properly managed. If they aren't managed properly, green or purple won't save you. Mold will grow on studs, insulation, trim or the surface of the paint just as easily.

Reactions: 5

avenge

· #17 · Jul 23, 2017

artinall said:
I've searched and there are no stores around here that have 1/2 inch purple (they'd have to order a stack).

With 1/2" green needing 12" joist spans (ours are 16" on center) -- would the 1/2" even suffice for the ceiling? Isn't the 1/2 purple less resistant to bowing than the green?

Since the 1/2" purple is supposed to be fireproof - do you really need 5/8 on the ceiling?

Only other option I can find now is to use 5/8 purple (the only purple around) on ceiling and 1/2 green on walls.

WTF? That's all I care to say.

artinall

Discussion Starter · #18 · Jul 23, 2017 (Edited)

Nobody here is of the opinion that greenboard is better than regular drywall when it comes to inhibiting moisture? But that it requires 12 inch OC for ceilings?

There will be no tile and a fairly strong vent has been installed (even though its preset tabs space it 1/2" down from joist). Just want to go that extra mile.

My thoughts (incorrect ?) are that the 5/8 green could be 16" OC

Regular 1/2" is stronger, that's clear.

-----------------
Then there is that argument that greenboard should be used without vapor barrier - by manufacturers (even on the plumbed wall?) This doesn't include kraft paper insulation does it?

hdavis

· #19 · Jul 23, 2017

Green board has wax in it, so it does better than regular if you have water on it. It can get wet and not turn to mush the first time. A lot of people just use it on walls around the shower, not on the ceiling. OTOH, I've done entire baths with it.

You shouldn't use a vapor barrier with it.

Reactions: 1

artinall

Discussion Starter · #20 · Jul 23, 2017

hdavis said:
Green board has wax in it, so it does better than regular if you have water on it. It can get wet and not turn to mush the first time. A lot of people just use it on walls around the shower, not on the ceiling. OTOH, I've done entire baths with it.

You shouldn't use a vapor barrier with it.

plastic vapor barrier? (Kraft paper okay?)

I've done a lot of drywall repair. Always, in baths, it has been where a ceiling fan went out, and it occurs right around the shower/surround.

My first question is always...have you been using the ceiling fan? Then I get that look.

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