[mseneker]

Well, sorry, started another thread. What backer board do you use in wet areas and why?

Backer board is board that goes behind tile on walls that get direct water such as from a shower.

We use concrete board. We have used Densshield. We are looking at hardibacker.

What suggestions do you have, keeping the following in mind:

Cost

Ease of installation

What do the tile guys like to see

Is the product tested and has no pending law suits

Availability (to include from nearby sources such as Home Depo)

Ease of skim coating over corners that will not get tile

Fire rating (can you use it over a wood fireplace that gets tile)


If you have time: List your preferred fastener!

[mdshunk]

Obviously concrete backer board is the superior product, but what about the yellow exterior drywall? How does the cost compare to backer board, if cost was the main concern?

[Drywall1]

We use aqua shield.

[Splinter]

One big item to keep in mind is that these cement boards are NOT waterproof. A moisture barrier is still required between the board and the studs. I use a membrane system when building showers which allows me to use drywall, but when I do tub/shower combo's, I usually go with Hardibacker. It cuts very nice with a junky blade in my cordless circular saw, and holes for the plumbing penetrations are much neater than anything you get with the concrete boards like Durock. The Hardi does suck up moisture like a sponge, so a few wipes with a very wet sponge are necessary before spreading thinset.

[thom]

I'll second what splinter said.

[Brockster]

Hardibacker using pneumatic stapler to fasten it. A bunch of tile guys around here use it all the time and like it but they (don't quote me)"red coat" to seal it.
I've had to pay for a tub that was chipped from concrete boards and that blows, I mean we should not even be asked to do the tile guys job in the first place.
So yes, hardibacker is easy to cut and install and way less chance of damaging tub or shower.

[Forry]

Originally Posted by Brockster

Hardibacker using pneumatic stapler to fasten it. A bunch of tile guys around here use it all the time and like it but they (don't quote me)"red coat" to seal it.
I've had to pay for a tub that was chipped from concrete boards and that blows, I mean we should not even be asked to do the tile guys job in the first place.
So yes, hardibacker is easy to cut and install and way less chance of damaging tub or shower.

Last time I read the James Hardi warranty, they wouldn't warranty the job if staples were used. For wet areas we use coated screws, Also, it needs a membrane behind or painted on 'cause it's not water proof.

[Brockster]

I'll check into that. In the pamphlet I read when I first used it 1" coated staples were suggested. I'll recheck that.

[mdshunk]

Originally Posted by Brockster

Hardibacker using pneumatic stapler to fasten it. A bunch of tile guys around here use it all the time and like it but they (don't quote me)"red coat" to seal it. .

I think that's called Red Guard. Sorta like paint-on rubber, the way it seems to me. Looks like pretty neat stuff.

[Brockster]

Originally Posted by Forry

Last time I read the James Hardi warranty, they wouldn't warranty the job if staples were used. For wet areas we use coated screws, Also, it needs a membrane behind or painted on 'cause it's not water proof.

I stand corrected! On the PDF file they say you can use staples for counter tops and floors.
Next time I'm at the supply house I'll grab a brochure and see what I read.

Thanks for the heads-up, Forry...

[Chris Johnson]

Does no one float walls anymore?

[mdshunk]

Originally Posted by Chris Johnson

Does no one float walls anymore?

I heard a rumor that there's this 78 year old man in Cleveland who's still doing mud jobs for tile walls.

[Chris Johnson]

Originally Posted by mdshunk

I heard a rumor that there's this 78 year old man in Cleveland who's still doing mud jobs for tile walls.

I think I met the guy

[Splinter]

You dont see guys floating walls all that often anymore around here.. Most "pro's" wont even try to get the shower walls plumb.... 2 coat floats are near non-existent, but single coat over wallboard is still done on the west coast.

RedGard is some damned expensive stuff... A layer of 6 mil poly behind the backer is considerably cheaper and a perfectly acceptable alternative. RedGard is great for recessed niches and benches where water has a better chance of getting in.

I use Kerdi, made by Schluter to do all my showers these days. It's a polyethylene membrane applied directly beneath the tile layer. 100% waterproof, and showers dry out faster, so there's less chance for mold and mildew to develop.

[Tom M]

Does anyone use poly as a flashing ? Say behind a board over the tub or base wall flange. I dont have history in bathrooms but I attended a seminar on moisture and mold recently. They discussed vented wall sytems or wall drainage sytems for the exterior. EIFS and stucco or stone veneer all are designed to weep out water at the bottom. Tile is similiar in system but more water proof. Whats behind is the second line of defense in failure or keeping moisture from wicking into the walls. So where will that moisture go under the tub or at the foot of the wall studs? It seems more logical to leave the base perimeter un sealed with-out caulk to drain any moisture? Then whether you use a poly, or surface sealer it can weep.

[Splinter]

Well, there's the problem that keeps me awake every night.. (OK, it really doesnt)

You want the moisture barrier (poly) to overlap the tub lip so any water will drain back to the tub, but then we all caulk the tile-tub transition... You'd imagine there'd be a puddle of water collecting there, right?

Truthfully, the poly is just a moisture barrier, not full-on waterproofer. It'll never see gushing water back there, it just keeps any vapor from getting into the insulation or framing. The moisture that collects on the plastic will eventually evaporate back through the backerboard and grout.

[savant]

I never trust poly or felt behind cement board. The only things I use are adhesive bitumin rubber behind the fibercement board, and redgard over parging on block.
There's a variety of ways to install the rubber, and it's self-healing.