I’m doing a tile tub surround and have already incorporated alot of the “best practices” advice from BT. Am hiring a guy to actually set the tile wall and floor…he did a great job so far on the floor and does the walls this weekend.
I’ve put up 1/2″ PermaBase CB backer board…taped (the approved self-stick FG stuff) and mudded the seams/fastener indents with thinset last night. I do have a few ridges and irregularities in the mudded surface…kind of like you would have after the first coat of sheetrock mud. I’m a good but slow taper…well beyond the typical DIYr that puts too much on and then sands forever.
The wall tiles will be stuck on with a mastic rather than thinset…the question is, how good does this thin set mudding job need to be under mastic? The mastic, I believe is alot thinner applied than thinset, and may not be able to fill in the irregularities.
I need to know about this soon, so if I have to go in with a second coat, it will be dry and I can be ready for the guy by Saturday afternoon. Also, does a second coat of thin-set take?
Replies
I can`t imagine any irregularities in the thinset coating so great they would require a feather coat.....is it not possible to just "knock down" any high edges?
Personally, I only use mastic to set the thinest backsplash tile. I`d recomend using thinset to install shower wall tiles....that is, if you plan to continue to follow "the best advice" of the BTimers. Thinset will (should) help compensate for any irregularities in the wall surface due to the filler coating. I included should as I`m not clear as to the extent of the irregularities.
J. D. Reynolds
Home Improvements
"DO IT RIGHT, DO IT ONCE"
Thanks for your response. The irregularities are just little ridges from the edge of the knife on its final pass over the wet mud.
Best practices don't include mastic in a shower. Tile and grout are not harmed by water, but they do allow penetration. Mastic is an organic material that will soften with moisture exposure. It might be alright for a backsplash, but don't use it in a shower.
Original decision to go with mastic made on recommendation of the tile shop where we bought the stuff, with the assumption that we were going to apply the tile DIY, said it would be easier for us (stickier on the walls.)
Now that we have hired the tile app out, I'll check with the installer...he may preferer thin set as well.
Thanks....
I'm DIY, but I tiled all my floors and bathroom myself. Thinset isn't that hard. Check out johnbridge.com and post your question there.
No matter what he prefers... no mastic in a shower. Never, never never. If he's done tile professionally before, he will not use it anyway. If the ridges are small, knock them down with a margin trowel... or don't. Thinset gives you some margin for error. Major bulges in your framing are another matter, of course, but what you're describing won't be a problem._____________________________HomeBase__________________________ LLC
Well, I guess that's something a DIYr has to be careful about when he goes to get advice from like a tile shop that obviously has salesmen working on commission...sometimes they'll bend the truth a little to get the sale....'cause I was told several times that mastic is just fine for shower walls, because I brought up the worry that I would have a hard time getting the tiles to stick on the walls using thin-set, but not having any experience in the tiling area or even ever watched a pro do it.
Not to take anything away from salesmen, cause I am in sales myself....probably why I smelled a rat, and took this Q to BT.
Looks like I'll be picking up another bag of thin-set today.
Saved again by BT!
Edited 12/17/2004 8:53 am ET by johnnyd
They don't bend the truth - they break it. I figured this out in '91. My experience since then has not changed my mind. This is another reason to go big-box.Les Barrett Quality Construction
I've never understood the contention that mastic is easier to use then thinset.
If you trowel on thinset and don't set the tiles set over that area and the mortar skims just take your margin trowel and scrap it off. If you get mortar on the tile face or anywhere unwanted, wash it off. Water clean up to for tools too.
I couldn't agree more Jeff. I did a mastic "wainscot" job a few years ago. What a freaakin mess. Thinset is a joy to use, and really is easy to manage once you get the hang of it... which even for a DIY doesn't take long. Mix small batches and go slow, and you'll be fine._____________________________HomeBase__________________________ LLC
It's said easy cause you don't have to mix it.
But If you have the choice stick with cement/thinset
Thin-set it was, the guy did a nice job...finishes up the grouting tonite.
I'm not sure if this applies in your case. I learned the hard way that if the framer did not crown the studs properly, you could have a problem when installing backer board. A straightedge should be held up to the midpoint of the wall height before placing backer board. If some of the studs do not meet the straightedge, I recommend putting a thick bead of construction adhesive on them prior to installing the BB. Then, tighten the board to the studs without adhesive first. Then, install your rock-on screws to the adhesive-coated studs only tight enough to not deform the backerboard. If the screws will not recess sufficiently to enable installation of the tile without deforming the board, wait long enough, perhaps a few hours, and then tighten them a bit more. This will help to ensure a minimum of ripples in the tile.
Permabase? Is this the rockboard w/ styrofoam pellets in it that 'SLowes' carries ?
Edited 12/16/2004 9:53 pm ET by JerryHill
I try to avoid relying on brand names in evolving products. Lowe's, HD, whatever. I prefer to think of the product as cementitious backerboard (CBB). I have noticed that there are great differences in appearance between some of the products that claim to be CBB. I would not let that influence my judgment in an ideal world. I have more confidence in the products that appear to be concrete cement in some type of fiberglass mesh. This is not to say anything negative about the current Lowe's product that seems to be of a finely-ground white grout-like consistency. My best guess is that any currently offered product that claims to be some type of CBB is probably as good as any other current offering.Les Barrett Quality Construction
I guess the point that I'm getting at is the product that I'm referring to isn't( in my opinion )very well suited for nailing directly over studs because it is n't ridged. Better suited for floors.I'm pretty sure it carries the brand name' Permabase'
Yes, PermaBase is some sort of cement with fiberglass embedded and little styrofoam balls. I think the function of the balls is to allow you to score and snap with a utility knife, which is hard on the blades but does work quite well with a minimum of dust. It also cuts well with a sabre saw, again minimizing dust....but it does a nice job of taking ALL the teeth out of the blades after a pass or two.
It does tend to deform a bit, but I think the I've achieved an acceptable plane where the installer can level things out a bit IF he uses thin-set with 1/4" grooves. I don't think that mastic can level out as much since its a thinner way to stick the tiles
I think that's the plan.
Thanks for the input.
Edited 12/17/2004 7:40 am ET by johnnyd