Stupid question, why are you doing the floor before finishing the drywall?
Who recommended a setting type joint compound (reinforced or not), for your cement based tile backer?
1) Because I thought it would be easier for me to tile a floor than a sloped ceiling--start with the easier part first then do the other. Also in no big hurry so could let the floor cure before moving on to the walls. That said, I'm now focusing on the walls/ceiling and will resume the floor once the walls are taped.
Originally Posted by dlarrivee
2) A contractor friend recommended con-fill for fixing spots where the HardieBacker had not snapped cleanly (corners etc.). From the name, I was assuming that it was primarily cementicious. However, having used it now, I see that it is plaster of Paris based, with some cement in it.
This could be a big disaster when I apply thinset over it--it could soften.... Now I'm hoping that the layer of AquaDefence will make this a non-issue when I'm installing the tiles. However, during the taping phase it could still be a problem. We'll see.
So much advice, so much to learn.... Appreciate all the help.
John - I'm glad your still plugging away at this and sharing your progress.
Cement Fill rocks up hard but really is not a proper backer material - that said if you can achieve 80% contact on sound backer board you will be alright. AquaDefence does stick and dry to cement fill. Once the Aqua Defence dries it will not reactivate the cement fill and make it mushy.
To add strength to these areas do you have any stucco mesh?
No mesh -- there are only a couple of spots inside the wet area that I used it -- to fill in broken off edge chunks of HardieBacker (1/4" x 3/4") and along the top edge of the shower head wall (where it meets the ceiling).
I extended HardieBacker into the dry part of the room (long story) so there I used the con-fill to skim areas that weren't perfectly in plane with each other and to fill some gaps where it met a non-true existing wall. None of these dry areas will be tiled so thinset compatibility is not an issue there.
We'll see how it stands up when I'm taping with thinset... Worst case it'll turn to goo and fall out, in which case I'll just replace with a few applications of thinset.
Still nice stuff to work with though :-)
I'm a fan of the cement fill myself John.
If you have some Aqua Defence you might try giving the cement fill a coat before thin setting. Nothing sticks to drywall compound that well. I have been trying different primers over drywall for some time looking for a good solution and have found that the Planicrete AC cut with water works well. The Grani Rapid liquid cut with water - not so well. I have some Mapei Prim Grip we are testing out as we speak.
I would imagine that any left over self levelling primer cut with water might work for a small patch repair. If you mock it up before hand I bet you find you get a better bite with both Aquadefence or thin set once these areas are primed.
Lets see some more action shots. I like pictures!
Sometimes it's super-handy having a little guy in the house who knows how to tape and mud!
Just did the taping and mudding in the shower area. Lessons learned:
1) Not all Fiberglas mesh tape is created equally. QEP Board Seam Tape is horrible: the glue is weak, the fabric is flimsy, and it just doesn't stay in place while thinsetting. Durock Cement Board interior tape is the opposite: sticky glue, sturdy mesh, and stays in place while thinsetting. No contest.
2) Mapei UltraFlex LFT works great over top of Synko Concrete Fill compound. No primer needed. Stuck just as well to the con-fill as it did to the HardieBacker. Really easy to spread and feather when taping.
3) The same rules for taping UltraFlex LFT over HardieBacker apply as with pre-mixed mud and drywall: stick the tape along the seam, press the UltraFlex LFT on thick with a 5-inch taping knife, then scrape off as much as you can on a 45 degree angle to the tape. No discernible buildup that will interfere with tiling.
3 pounds of UltraFlex LFT did the entire wet area and gave me almost exactly an hour of working time.
All in all, a great experience. :-)
Sorry, I'm afraid to see the results of the mud and tape job on the drywall.
Ah, ye have no faith in his teacher... The little guy's workmanship is much better than the contractor we let go in December...
Here's how it looked after the little guy skimmed the far wall, and mudded the wall side of the tape on the right wall. No sanding done yet. Ceiling thinset still to be done.
14" of joint compound for an inside corner?
Since you're teaching, show your kid how to hold the knife properly.
John what is this room? Is it a storage locker?
Originally Posted by jch
Love the use of Child Labour! My three girls are always helping me with something. My eight year old seems to love the trades the most and my youngest six year old loves working with hardwood. She helped David and I with the face nailed floors we are installing in my home. The oldest - is all about the delegation.... lol
Wow, tough crowd... :)
It's tough to tell the scale from the picture but this is a 13" wide cubby in the bathroom. The mud is one 6" knife-width wide. This area will hold towels etc.
It's not Child Labour if you don't pay them... they're apprentices... ;)
When asked, my daughter would always say her favourite part about Grade 6 was working in the woodshop. They used to open it up during lunch to whoever wanted to use it and she and her 2 friends would go in and have the run of the place. She made some really beautiful stuff out of maple, mahogony and oak.
My son really likes making stuff too. He keeps asking whether he can have the leftover scraps of Ditra -- not sure what he has in mind but I know it'll be cool.
Everyone has to start somewhere...
Just about done prepping the room and finalizing the grout line placements...
What thinsets / trowel sizes would you recommend for the following? I've linked to the product pages below in case you need to see the tile specs.
1) Ames Radiance, 12x22" (landscape)
- Installed over HardieBacker/AquaDefense on shower walls *and* ceiling
- Thinking of 1/8" grout spacing
- Would like to use LASH system
- Considering using Mapei UltraFlex LFT White to make it easier to do the sloped ceiling -- good choice?
- What size trowel? 3/4" square? 1/2" U? something else?
2) Ames Sedona Marble Mosaic (Aspen), 1x2.25" Honed Marble Mosaic on 12x12" sheets
- Installed over HardieBacker/AquaDefense on entire backsplash wall behind sink
- Mosaics are 1/8" nominal grout line (some variation)
- Includes some white marble(?) so am concerned about discoloration from thinset
- Would like to use medium grey grout (matching medium stone in mosaic)
- No idea what type of thinset to use. UltraFlex LFT White?? Something else?
- What size trowel? 1/2" square? V-notch? Concerned about thinset squeezing up between joints
3) Ames Fibra (Sage), 12x24" Rectified Porcelain
- Installed on floor over Ditra
- 1/8" grout line
- grout colour same as #2 above (medium grey)
- Because it's porcelain over Ditra, I'm pretty sure I have to use an unmodified thinset like Mapei Kerabond.
- Want to use LASH system
- What size trowel? Same as #1 above?
The tile wholesaler won't be open when I'm doing this, so I'm hoping to get all the supplies I'll need up front.
I called Mapei to get their opinion and here's what they recommended for thinset types and trowel sizes:
1) 12x22" ceramic on walls & ceiling in shower over top of HardieBacker & AquaDefense:
Mapei UltraFlex LFT
Back-butter tiles (thin 1/32" - 1/16" layer with straight edge of trowel)
1/4 x 3/8" square-notch trowel
2) 1x2.25" honed marble mosaic for entire wall behind sink:
Mapei UltraFlex LFT *White*
3/16" V-Notch trowel
3) 12x24" Porcelain on floor over Ditra:
Mapei Kerabond - mixed according to package directions (add up to 5% extra water for Kerabond *under* Ditra)
Try 1/4 x 3/8" square-notch trowel, but may need to move up to 1/2 x 1/2" square-notch trowel if not 100% coverage
Hopefully this'll help someone else whose using similar sized tiles.
Originally Posted by jch
Great Information John.
Thanks for sharing. You are setting the bar very high with your research. I'm sure your project will help thousands of people with question in the coming years. Well done!