Before I go and commit to this, and after way too much reading and research, this is my plan.

Background: new fiberglass (Vikrell) tub, 60" x 32" in an alcove built for it using Kohler-Sterling's instructions (lots of studs). Ceiling is about 63" up from the installation flange of the tub. Tiles start 1/8" above the highest horizontal surface on the tub.

I will tile the ceiling (63" is about 2" above the shower head). The tiles are 6" (wide) x 8" (high). The decorative pattern on the top row and on some of the tiles pre-determines that 6" is the width and 8" is the height.

I was heading towards DensShield or Wedi until I read that the DS is supposed to be waterproof and no other membrane should be used, and I do not have confidence in DS alone. I am confident about Kerdi from Schluter, and the supplier tells me to use green drywall thoroughly sealed with Kerdi. I would be confident with Red... (forget the whole name of it).

Wedi has not yet replied to my email request for where to buy in Canada, and so I have yet to ask them whether I could use Wedi and Kerdi or Wedi and RedXxxxx.

So, that's the plan:

Ceiling, 3 walls, and a few inches out from the tub, sealed with Kerdi, and tiled with ceramic.

I have purchased DensSheild from Home Depot and applied it to my tub Surround and will be using it in my shower as well. It sells for approximately $16.99 a sheet (3" x 5") and is fairly easy to install. I have also used Red Guard with it, on the thinset areas (i.e. Screw Heads and Joints). I found this combination to be easy to use as a DIY'er. Believe me, I have pestered Randall and Harry a ton before I decided what to use. Now I made a huge mistake and had to replace a few sheets, if you do use this "DO NOT" counter sink the screws, Make sure that they are flush to the DensSheild. Basically read the Installation instructions a couple times. Here's an excerpt from their website.

"Blocks moisture. Resists mold. The proprietary construction of DensShield Tile Backer integrates a moisture-resistant core with fiberglass mats and a unique heat-cured acrylic coating. The result: the only backer in the industry with built-in moisture and microbial barriers. That means DensShield keeps moisture where it belongs - in the tub, shower, or pool"


http://www.gp.com/build/product.aspx?pid=4684

Thanks, Mike. Around here, I found it at Reno-Depot (called the G-P sales rep to find out after 2 futile trips to HD and a different Reno).

I have read and read (read the part about screwing to flush and w/o counter-sinking). It is appealing to me to use it in the ceiling (light weight), but I would have to first call G-P to see if it is compatible with RedGuard or Kerdi.

What country are you in? Shopping in Canada is different. I can buy in the US, but HD is far and Lowe's may or may not have RedGuard. Maybe someone in Canada also has it.

Maybe time to call G-P about the 2nd layer of water-proofing because I like the idea of how light it is. $17 each, sounds right. Nothing about this job is bargain basement and I will have it done right and to my satisfaction before I will go for "cheap".

I returned a $40 exhaust fan at SONE 4.0, paid $160 for a SONE 1.0 model.

At "pushing 60", this is the first time I will have a "nice" bathroom (nicer than...), not luxurious at all, and it will be the last one I build. It will outlast me, but I intend to soak in that tub without listening to a jet engine taking humidity out of the room.

The mold in the old bathroom put me into the hospital, so I am particularly determined to do this right.

I really would rather use Wedi or DensShield than green drywall.

Well, it only took 15 seconds to get through to Becky at G-P gypsum product support. She emphasized no moisture barrier behind the DensShield but assures me that a waterproof membrane in front (RedGuard or Kerdi, I specified) is just fine.

I like the light weight, the "right size" of it, and that it is impregnated with mold resistance (and all the rest of it). Green drywall is just so totally inadequate that I do not like the idea of having it there at all.

I phoned the Wedi rep for Eastern Canada. The big box stores do not carry Wedi. He gave me the name of Mondial Tile in Montreal and the name of a person there. Good thing he did because everyone else there never heard of it. He is out for the day, but they sent him my phone number by email.

I like the styrofoam core of Wedi. I know that styrofoam does not get weird in humidity (even though I have seen coffee mugs sweat). I am so pleased that "environmentally friendly" has largely made those stupid cups disappear because I loathe drinking from them, but I digress (you will get used to it).

I have never used anything but plain drywall behind Kerdi. It's what is recommended by Schluter. It's cheap, easy to work with, and doesn't require a lot of tools. Since Kerdi is going to block any moisture, there's really no point in having a waterproof backer.

On rare occasions when I use CBU (which is usually around a tub) I use Redgard, which is available at Home Depot. But I buy it in a 3 1/2 gallon bucket and can use it on several jobs, so none of it is wasted.

If I was going to do one tub and didn't have any plans beyond that, I would probably use Kerdi, since it can be ordered by the square foot and can easily be installed in a couple of hours. With Redgard, I think the smallest amount you can buy is a gallon, and the chances of you having the exact amount are rare. So it's possible to end up with some left over that's wasted, or having to buy another gallon and wasting even more. It also has to be installed to a minimum thickness to meet the warranty standards, so you would need a thickness gauge to get it right.

One way you could make your job easier is to waterproof only to the height of the shower head. No significant amount of moisture will get above that height.

Can you tell I've never been a big fan of the 'waterproof backers'?

Hi, Kayman. I should mention that drywall is made of plaster and that my house is full of plaster and lime dust (150 pounds of lime to disinfect the soil in the crawl space when tub and laundry emptied under there). Old materials thrown under the floor into the crawl space got wet and rotted. That had to be removed.

For the dust alone, I will use Styrofoam backer board. I don't care about what is left over in a container. I do not want any more dust or cement and sand bits in here.

I had a teaspoon of ABS glue here from 30 years ago. We bought a truck full of ABS and the only way to have a bath that day was to glue the new drain in. Home Depot had not a single container of ABS glue and nothing else was open within 20 miles.

We used my teaspoon of 30-year-old ABS glue. That was redone later, but it worked for a week or two that I needed it.

I want to waterproof the waterproofing, ventilate the ventilation (I am installing 2 ventilation systems with remote hygrometer and thermometer), and heat the heating. I have a gas furnace, a wood stove, and electric heat, and generator for backup.

I wear a belt, suspenders, and a magnet on my head that pulls on the metal button on my pants.

My shower head is 2" from the ceiling. My ceiling is 13" taller than I am. I can barely fit an 80" door into the wall and there will be no space for door trim. The ceiling will be waterproofed and tiled, even if it is totally unnecessary.

I am not looking to cut corners. I am looking to not redo this again ever, and to never again end up in hospital because of mold.

Somebody told me 1/8" "does not matter". I told him that everything matters, took him off the job, and a week later learned and showed him why 1/8" matters.

Everything matters. No shortcuts. The budget was blown weeks ago. I can sell off a couple of the kids but nothing will be done carelessly.

Hi everyone,

I like the Kerdi installed over regular wall board. Since you wanna go a different way, I think Denshield is OK for a tub surround. (I would never use it for a stall shower when the floor will be tiled too. Ask me why).

You do NOT want to apply a vapor barrier behind the DS, or apply one on the entire surface. Maybe just a dab on the faster punctures or over the thin set over the seams. There is no need for it, and it may create problems esp. behind the board. We call that a "vapor sandwich" which is not a good thing.

Jaz

Yes, that vapor sandwich interests me. I have not seen it well explained anywhere yet, but the warnings against creating the environment for it make me see that there is something to know there.

My far short wall (tub/shower) has a vapor barrier, so now I don't know whether I should just put drywall and Kerdi there, or pierce the barrier or what.

I already lifted a floor where the guy put plastic under the plywood and then broke a pipe. Water trapped between plastic and plywood I was definitely not going to have.

I made him remove the plastic and caulk the gap between the sheets of plywood. I had already asked him to do that and he said "It does not matter."

The end wall is the outside wall with 8" of insulation and 6-mil plastic vapor barrier.

What's the purpose of caulking between the sheets of plywood?