Hello All,
Once again I am seeking some advice. This time it’s on how best to prepare surfaces in preparation for tiling. I recently gutted the main bathroom and am at the point where it’s time to tile. I installed 1/2″ Hardie Backer on walls surrounding the tub and to a transition with green board at the approximate location away from the tub where I will end my tiling. During room spacking, my drywall guy spackled where Hardie backer was extended to an outside corner. and the opposite wall where where I transitioned to green board. I think I should I scrape away the spackle so that I am applying adhesive directly onto the Hardie Backer and green board and not the spackle surface. Agreed?? By the way it is porcelain tile.
A brief second question… my tile supplier sold me tile adhesive. North American Adhesives NA2040. It is supposed to be for both walls and floors. I have a friend who says I should always use thin-set mortar for the floors. Floors are also prepared with Hardie Backer. I will be doing the bathroom floor and a foyer.
Thanks so much,
Geoman
Replies
I am a good carpenter...
...and not much of a tile guy. So I can't answer your questions with any authority.
But, here are couple of articles from the archives and videos from fhb.com that may be helpful to you:
Tiling a shower video series-- yes, it's a shower, not a tub, but wet walls are wet walls: https://www.finehomebuilding.com/pages/tiling-a-shower/
Tiling a bathroom floor: https://www.finehomebuilding.com/how-to/articles/tiling-a-bathroom-floor.aspx?collection=86648
What's The Difference: Tile Setting Compound (FHB#196) https://www.finehomebuilding.com/how-to/departments/what-is-the-difference/thinset-vs-mastic-tile-setting-compound.aspx?nterms=61950,62158&ac=ts&ra=fp
Tiling a bathroom floor video (cutting tile around a round toilet flange): https://www.finehomebuilding.com/how-to/video/tile-floors.aspx
Tiling a tub surround: https://www.finehomebuilding.com/how-to/articles/framing-and-tiling-tub-surround.aspx?collection=86648
Tiling a backsplash video series (has a section on thinset): https://www.finehomebuilding.com/pages/tiling-a-backsplash/
A Sloping Floor for a Barrier-Free Bath: https://www.finehomebuilding.com/how-to/articles/sloping-floor-barrier-free-bath.aspx?ac=ts&ra=fp
Some of these are available to all, some are available to members only.
Hope that helps at least a little bit,
Dan
You'll get mixed opinions about using tile mastic for shower walls, but almost universal agreement that only thinset or something similar should be used for floor tile.
Tile mastic is fine for dry or semi-wet areas (backsplash or around a non-shower tub), though some types of mastic sag rather badly and won't hold tile on the wall for even a few seconds unless you shim them.
If you are using mastic, though, there's no problem with using it over drywall mud or similar. (Though ideally the mud used was the setting variety, or a water resistant spackle.)
Using thinset over drywall mud or spackle is more apt to be a problem, especially if it's drying-type mud.
I am not a "tile guy" either,
I am not a "tile guy" either, but I have been doing lots of tile projects while building my house, and I am a little anal about doing research before I start anything. I agree 100% with using thinset for floors. Some premixed tile adhesives say that they are rated for floors, but none of the professional installers I have talked to trust anything premixed for floors. Bags of latex modified thinset would be much better for the job. For the walls in wet areas, most installers preferred thinset. In dry or only occasionally damp applications, the adhesive would be fine. Mastic is easier to work with and doesn't require you to mix it, but thinset chemically cures, so it doesn't matter if it gets wet. I also did some tile ceilings in showers, and I used thinset. I supported the tile on the cieling with screws and big fender washers while the thinset set up to avoid having a tile shift and come crashing down. Not sure if it is the best or easiest way, but it was very effective.
As far as the spackle: is it a few little pieces of spackle, or did he coat a big section? A few little pieces shouldn't make much difference, but if he covered big sections with drywall mud, it could soften when it gets wet and affect your tile job. If you are not sure what he used, wet the mud and let it sit for a minute. Then see if it has softened or if it is still hard. The setting-type mud shouldn't be a problem, but the bucket mud could cause problems. Scraping will help, and if it is stubborn, spray the area with a little water, wait a few minutes and try scraping again.
geo
I have used a waterproofer called RED GUARD, made by Custom to seal that tapering mud transition from cement board to drywall. It will not soften and does waterproof the area in question. Thinset adheres to it well. Run the Red Guard to within a half inch of finished line on the drywall. Take your tile over that RedGuard edge to the finish line. The half inch over the mud won't kill the tile job.
Other brands make the same product. Red Guard is an ugly red-don't slop it around or go past the tile line.
Absolutely use thinset and not mastic. And I hope you installed a waterproofing membrane behind the backerboard. If not, you or someone else in the future will be tearing out a rotten mess some day. Use the Redgard if you didn't install the membrane. Or, you can tear out the backer, install sheetrock and Kerdi. That's the cat's meow.
You can learn a lot about tiling and the proper prep at http://www.johnbridge.com
why cant he put kerdi over the cbu?
Thank You!
I just wanted to say thank you all very much for taking the time to reply to my post. Your comments and suggestions were all very helpful and I am reassured on how best to proceed. Red Gurad eh?
Be well,
Geoman