| Author | Message | ||
| Scott Whitney (63.151.64.84) Rating: |
I posted this question over on MAKs BB a few days ago, but haven't heard any opinions yet. It is touched on in another thread on this BB, but it is archived and I can't seem to post to that original thread. But I'd like to toss the idea around a bit if possible . . . Should Wonderboard, Dens-Shield or just plain plywood be used to back tile? My floor consists of: (1) tar paper, (2) 3/4" plywood, (3) 1" furring strips on 16" centers & 1" foil backed foam sheathing in between, and finally (4) 1/2" plywood. Should I put AdMix or 333 Superflex thinset directly on this surface or use a backerboard first? This is for kitchen & bathroom floor and shower enclosure (10" or 12" and 1" tiles respectively) Thx. Scott | ||
| Jack Conrad (Jackconrad) (204.193.117.66)
Rating: N/A |
Scott, I have seen tile installed directly on the plywood in second story homes using thinset with latex admixture. When tile removal was attempted, some of the plywood came up with the tile. This is how we plan to intall our tile. We plan to install all cabinets first. Leave 1/4" "grout line" around edge, then fill this with a caulk that matches the grout. This will allow for expansion with temperature changes. Hope this helps. Jack Conrad | ||
| Jim Ashworth (Jimnh) (205.188.193.13)
Rating: N/A |
For shower walls, cement board should be used with a tarpaper moisture barrier behind it on the studs. For the shower floor, use a copper pan and contoured concrete(mortar) for the base. Grouting on the shower floor tends to crack and lets tons of water through a crack so small you can't see it. For a kitchen or bathroom floor, plywood is fine, as long as the latex admixture is used. Although it is a real pain, use the admixture in the grout as well. (It's really tough to clean up cause it sticks so well) Cover the plywood joints with fiberglass tape so cracks don't develop and you should be ok. Jim | ||
| Scott Whitney (63.151.64.84) Rating: N/A |
Thanks for the advice! I was at Home Depot yesterday and saw some of the products. One last question: Has anyone tried to use straight silicon instead of grout? Seems like it would be easy enough to replace the silicon every few years when it wore out or got grungy looking. Or is that much flexiblity unneeded? | ||
| Jim Ashworth (Jimnh) (172.129.242.244)
Rating: N/A |
Scott- Put the grout in and never have to go back and replace it. Done with the admixture you won't have to worry about it. However, along the cabinets, its an option since the wood will swell and shrink with the humidity, cracking the grout. But, unless you swab the deck with a wet mop, the grout should do OK there too. In the shower, silicone is great where the wall meets the ceiling since the bus shell WILL expand and contract daily as the sun hits it. If you have a corner at the shell wall, consider "floating" the corner by anchoring the corner joint studs to each other and the interior wall section only and not to the shell wall. The rest of the studs along the outside can be anchored to the shell, but the corner can separate as much as 1/8" if screwed to the shell. There will be enough flex in the concrete backer board so the shell expansion will be taken up over the stud spacing (12" or so) and will not crack the grout or tile on the outside wall. That's a little confusing. One picture would clear it up but I don't have any of that detail. Jim | ||
| Donn Reeves (12.89.144.114)
Rating: N/A |
Scott,I have ben building houses and doing my own tile for 25 years,and in my experience tile over 1/2" plywood will flex and crack.It would have been better to have put the 1/2" ply on the bottom and the 3/4"on top.As it is too late for that,defiantly go with "wonder board". Thinset it down to the plywood,stagger the joints over the plywood,and thinset w/fiberglass tape the joints in the wonder board.Hope this helps. have fun.Donn | ||
| terry-hawaii (66.8.194.104)
Rating: N/A |
I agree with Donn on this. Use wonderboard (heavy) or 1/4 inch Hardibacker. This can be screwed and glued on the plywood and then tiled. Should hold up just fine. Ours hasn't cracked yet and we regularly get earthquakes here in the 3-4.5 range. You can get grout with latex already in it so you don't need admix. If you want it solid though, you need 3/4 ply backing on the floor. Also, I'd use a shower pan, not tile on the floor | ||
| Clarke Echols (216.17.134.83)
Rating: N/A |
Put 1/4-inch Dens-shield down on the 1/2-inch plywood and set sheetrock screws (trumpet head) long enoug to reach through to the 3/4-inch plywood on the bottom. Set screws on 6-inch centers or less (4 inch even better), then use an epoxy thinset. This provides an unconditionally waterproof barrier from tile to wood substrate that you cannot attain with wonderboard or other concrete type processes. Dens-Shield is an INDUSTRIAL/COMMERCIAL product that can take the abuse of sports arenas, etc. Wonderboard is not waterproof. If you don't believe it, take a short piece of plastic tubing or pipe, set it on top of the wonderboard/sheet-concrete, seal around the base with RTV sealant/adhesive, then when it is set up, pour water into the tube and see how long it takes for the water to drip through to the bottom of the wonderboard. You can submerge Dens-Shield in water for a full year and it will not deteriorate, and it will not pass water through it from one side to the other. It has not been marketed to the home-builders market, so tradesmen who have been in the residential building trades are not in a position to have an opinion about the product unless they've used it. It is manufactured by Georgia Pacific, and is a silicon-impregnated gypsum product with acrylic surface finish ready to accept thinset adhesives. |
