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krystyl_clear 09-09-2009 12:18 PM

Help with the next few steps...please.
Some background. I purchased a foreclosure for 50% of the value of the house. There were original hardwood floors under the carpet, 1x10 lap cedar siding, and a few other things that made the purchase worth while for me. One major problem was the bathroom. The shower plumbing add-on was on the exterior of the wall, the tub faucet leaked molding and rotting the wallboard causing the tiles to fall off. I tore out the flooring to the subfloor (1/2Ē tongue and groove), put down 1/4Ē plywood under 1/2Ē Hardibacker on the floor, turned the built-in closet from the bedroom into the bathroom, took off the wallboard from around the tub, killed the mold in the walls, put up my Hardibacker with the proper screws. I need help on the layering of the next few steps. I will be tiling the floor with 12x12 and the tub surround will be 6x8 laid lengthwise on a horizontal. The rest of the bathroom will be done with American Clay, including the ceiling.

1. I need to seal the joints. Iíve already used a silicone caulk (Kitchen, Bath and Tub) between the pieces of Hardibacker, between the Hardibacker and the studs, and the Hardibacker and the tub. What kind of joint compound and wall tape do I use? Can it be regular joint compound and mesh wall tape that I already have?

2. Do I use this same stuff for the joints on my floor? Or do I use anything on the floor?

3. Should I use a brush or roller for the Redguard that I have for the tub? Should I use it on the floor as well?

4. Iíll use a board to level the first layer of tile (second course - Iím using thinset). Should I butter the backs of the tiles at all when applying them?

5.I need to use a base for the clay on the rest of the walls and ceiling. Can I put the sand in the Redguard for the rest of the bathroom, or should I put down the Redguard and use the sand in a product like Kilz and paint over the Redguard before the skimcoat of clay?

I appreciate your assistance and advice...snarky or not. (I actually learned all the previous stuff from watching TOH - You were great teachers. I'm just hoping that I'm as good a student!)

PaliBob 09-09-2009 02:15 PM

Krystal, Welcome to the forum and congratulations on your deal and your new crusade.

How about including your location and some Pics. You can see everything in your sleep while we can only imagine what you are describing. Go over to the top post on the Building & Construction Page to see ďHow to attach a PhotoÖĒ.

I did not see anything about changing the original Plumbing or Electrical is that all done now to code? What about the Bathroom Fan? If you are not absolutely sure post over on the Construction or Electrical page.

How did you decide to tile the ceiling?
What are the Bathroom dimensions?

Krystal, I see your note on T.O.H.
I met Tommy Silva at the 2007 Las Vegas Remodeling Show. He was there as a spokesman for Andersen Windows. That guy can do anything. His main message was Ďthat water is the enemyí, We got to talk a little after the Show and he is as personable as he is knowledgeable.


krystyl_clear 09-09-2009 03:36 PM

1 Attachment(s)
Thanks for your response, Pali. My location is Yakima Washington, which is between Seattle and Spokane and slightly south. The pics will come soon.

The very first thing I had done was put in a ceiling fan, new wiring, switches and plugs. This is a 1950's that no one ever updated. That gives the explanation for the mold being as bad as it was. I have an Electrical Engineer and an Electrician in the family and will be re-running the entire house in a couple weekends. Right now there is old wire that is wrapped in insulation and clothe. The wire itself is quite thick and the casing tends to look burnt. I donít trust it.

A plumbing friend told me what I needed to get for the plumbing for the bath, which I installed myself, but the toilet and the sink plumbing stayed the same even though I am changing both fixtures. Yes, I took pictures for any inspector, but itís now already enclosed. Both situations are to code.

The dimensions of the bathroom are 9íx6í with a 4íx2í-6Ē closet behind the door.

I hope the attachement gives you a better idea of what Iím talking about. Right now thereís no toilet or sink. I originally wanted to tile all walls, ceiling and the floor, but when I saw American Clay used I decided to do the three walls of the tub and the floor. Iíll clay the rest including the ceiling.

I was a concrete mason for years, but now Iím a designer. Iíve watched all these shows since I was young. (I think Bob Villa had black hair!) Now I get to put to practice what they taught me.

JazMan 09-09-2009 09:17 PM

Next time, (and for everyone else just reading this post), do not use 1/4" ply on the floor when installing tiles. You should have done the opposite on the floor prep. Next time use 1/2" or thicker underlayment grade plywood and 1/4" backer board. Backer board adds no strength no matter how thick, and the 1/4" ply adds little, while 1/2" ply does add structural strength. How did you kill the mold on the studs and back of the other wall?

1. Caulk in the joints of the backer board?:no: Where did you learn to do that? It's OK to caulk between the board and the tub, but that's it. You apply modified thin set mortar in the joints, then apply the special fiberglass mesh tape, then another thin coat of thin set and smooth it out with a 6" knife. Never use regular drywall compound.

2. All joints are treated with the special mesh tape and thin set.

3. Use either, but I do not recommend applying it to the tub, just the walls. :wink: Floors do not require a membrane.

4. No need to also back-butter if you apply the correct amount to the walls.

5. No idea, I don't do clay. :laughing:


krystyl_clear 09-10-2009 09:27 AM

Thanks Jaz!:thumbup:

The first thing I did to eradicate the mold was to find the cause of the problem, namely the leaking plumbing and the fact that there was no exhaust fan in the bathroom for the last 50 years! I removed all the infested board, fixed the plumbing and added the exhaust fan. I used a sponge and a 50/50 mixture of bleach water and removed the surface mold on the studs and back of the other wall. I let that dry and inspected it to see if the mold had permeated the wall board and didnít see any evidence, then sprayed the areas with 100% bleach letting this dry without rinsing. I repeated the process two more times over the next week. Then I waited two weeks to see if there would be any re-growth. I conferred with a Haz-Mat specialist at my work and they said this would be sufficient. With your questioning, though, I hope it was.

1. Early in my career as an apprentice, my boss used an underlayment glue when putting down the sub-floor. My could work with Silicone on the walls...:whistling2: Now I know better.

If I ask at the specialty store (Ace, Lowes, Home Depot) about this fiberglass tape, they'll direct me to the right one, or do you have some names that I can drop to be put in the right direction?

2. Will do. :thumbsup:

3. <blushes> Duh... I guess that did come out kinda funny, but you got what I meant. Thanks.

4. Since I'm a tiling virgin, but fairly skillfull at construction, I have a 1/4x1/4 sq notch trowel. I'm laying 12x12 on the floor and 6x8 (horizontal, lengthwise) on the walls. How thick, do you recommend, should the thinset be for each area?

5. Aww...I'm finding that using a trowel is using a trowel, whether for this, concrete or clay. I'm sure if you put your skill to work, you'd be good at it too. :yes: So, who do I talk to about the clay question?

PS I'm not too late about the flooring! I'll take your advise and switch it the ply and backer thicknesses! Better late (if not too late) than never. Do it right the first time and you don't have to do it again!

JazMan 09-10-2009 09:18 PM

Removing the affected moldy areas was the right thing to do. Many people wouldn't go to the extent you did. If your Haz-Mat. friend thinks what you did is fine, who am I to argue?:huh: All I know is that bleach is NOT a good mold killer when used on porous materials. Next time consider using this:

I have heard high praises and I used CONCROBIUM once in the empty house next door.

The correct tape is known as backer board tape. or something like that. The whole idea is that it is mildew proof. Shopping for specialized materials at those big box stores is done at your own risk. You need to know what you need cuz good advice is hard to find.

I recommend a 1/4x3/8x1/4 trowel for large tiles, but the texture of the backs influences the trowel. 1/4x1/4 may work too, but I'd have the larger one handy too. As I said it depends on the tiles, the consistency of the mortar and how you hold the trowel.

Good idea to switch to thicker plywood. Be sure to use an underlayment grade and NOT the cheap CDX stuff that will tempt you while shopping.:thumbsup:


krystyl_clear 09-11-2009 11:38 AM


Thanks for the recommendation of Concrobium and now have bookmarked the site for future use. Since I lean to the "green product" side of things when I can, this is a great reference. :thumbsup:

Because my choice of supply shops is limited to the big box stores, Iíll head your warning and read the packages for manufacturerís recommendations for the tape before I choose a product. Most of those places have several types, in several different places within the store. Iíve made this mistake before with other products and the cost alone is reason for considering the source of the advice when choosing. :(

Iíll get the second trowel for the larger tiles, since the right tool is the best for the right job. :thumbup: Plus itíll be in my toolbox for the next time too. You mentioned how I hold my trowel. It depends on what Iím doing. I hold my 10 different than I hold my Darby, than I hold my pool trowel... sponge float... edger... well as what I need done. If it would be better if I held my trowel a specific way (flatter, 45^, 90 to the surface, etc) to create a better product outcome, then by all means, let me know how you do it. :huh: Could you be more clear on what you mean?

Will do on the underlayment!:thumbup:


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