Walls or floor first ?

I am almost ready to tile a bathroom. It is a 5x8 and was gutted to the studs 2 layers of new plywood on the floor. I am installing Hardiebacker around the tub all the way to the ceiling. 1/2" Green board on the rest of the walls. Should I start with the walls for tiling or the floor? Walls first seems to make more sense to me.......

In either case, you need to protect the floor, since you don't want a bunch of thinset or grout on it prior to starting to tile it. I'd probably do the walls first.

Remember to use the proper tape on the cbu joints, and the correct industry approved thing is caulk at the change of plane and materials (i.e., corners and tub to wall). If you want to avoid caulk entirely, there are some expansion joints that can be tiled in. Check out www.schluter.com for some.

If your two layers of ply are properly installed (and the installation is very specific), you can use a highly modified thinset on the floor rather than cbu or a membrane. But, for ease of installation, and better performance, I like to install Ditra, also from www.schluter.com. It has the advantage that you can carry all you need up in one trip, it cuts easily with a knife or scissors without nasty dust from the cbu, and no taping the seams or fighting with the screws to anchor it without jacking the panel or cracking a corner.

The best place for tiling info is www.johnbridge.com.

It depends on what you are using for the wall/floor joint. It really depends. It takes more skill to make the wall/floor joint look good if you do the walls first, but it doesn't really matter. If you end up using something like a cove tile or an expansion joint (like those made by www.schluter.com), again, it doesn't matter.

In either case, you want to protect either the subfloor or the finished floor when doing the walls...you don't want globs of thinset or grout on the floor. If you do the floor first, and drop something heavy while doing the walls, you may crack or chip a tile. So, again, pick your poison...you can do it either way.

tile

If you are using a "coved base" to create a radius where the walls and floor meet, then do the walls first, and cut the floor tile to fit it. Otherwise, it depends on whether you want to see a grout line in the floor at the wall, or a less obvious one where the wall meets the floor. Doing the floor first means you do not have to be a precise with your cuts, since they will be hidden.

I think I like the idea of doing the floor first for the reason HJ gave. I took some scrap cardboard and used it to simulate the joint. Looks better floor first.....

I always do the floor first. I second the Schluter products. The dittra is awesome, especially for custom showers.

Spaceman Spiff said:

The dittra is awesome, especially for custom showers.

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Ditra is for floors, Kerdi is for showers, although you can use Kerdi band to waterproof the seams of Ditra if you need to on a floor (not generally necessary, but may be in certain cases).

Industry standard calls for caulk at the wall/floor joint, so a cove tile is best left for tiling on a mudbed and mudded walls, not today's cbu more typical construction. If the floor tile edge is covered by the wall tile (more common and easier thus it's done more often), then you could hide caulk there. What you absolutely do NOT want to do is to grout the floor tile tight to the wall studs. You'll have a high probability of a tenting failure when the floor and the walls expand and contract at different rates. Take a piece of paper; lay it on a flat surface. Mark one end, then push one edge as little as say 1/8" and see how high an arch the paper makes...it doesn't take much to break the bond if the tile can't expand.

Anyone use the Durock membrane ? I saw it on their website and it looks like something that could help with water proofing around the edges. I was thinking of using it but it's an additional $125 and this is just a 5'x5' floor area! I tiled this bathroom in 1971 and it was heavily used for years and years by the same tenants. The floor was a pretty bad but it probably should have all been ripped out in 1971. I believe I just replaced the subfloor with plywood and tiled directly on that with mastic. I don't want to do this again anytome soon! The bathroom is on the second floor directly above the kitchen area. This is a lot of work but it should be pretty nice when it's done. I am going to put a Toto Vespin in there. A little extra room will be good as the rough in is at 14". The toilet supply has been moved to accomodate the skirted toilet.......

The reason to use a product like DUrock is because it acts like a good isolation barrier between the tile and the wooden subfloor. You don't really want to use mastic on the floor, especially if you are worried about moisture! Mastic stays flexible in the bucket because it can't easily dry out. But, once it does, adding water makes it flexible again! Not good in a potentially wet area. Plus, it costs probably 2-3x as much as a decent thinset. The thinset has cement in it, so once it cures, getting it wet won't cause it to soften again. Use the dry stuff in a bag you mix with water. Don't chose the cheapest version, but you don't need the most expensive. DON'T tile directly to a single layer of plywood. If you want to tile on plywood, you need two layers, and a very expensive thinset. If you use DUrock or any other brand of cbu, make sure to follow the instructions and install it with thinset underneath and use either hot-dipped roofing nails (not electroplated) or the proper cbu screws to anchor it. Then, tape the seams with the proper tape - it may look like mesh drywall tape, but is made to not break down in the thinset. Leave a small gap at the walls, and it should last a long time (if the floor structure is stiff enough!).

Durock makes a thin membrane sheet that you roll out and use adhesive to stick it down. I do have 2 new layers of 5/8" plywood screwed and glued to the joists. Last night I used a straight edge and found a little high area in the center of the floor and sanded it flat with a belt sander. Framing was really pretty poor previously but I did a lot of reinforcing by sistering in a lot of lumber. The construction on this house was very poor back in the 1950's. I don't know how it ever got put up the way it was built.


Here is a link to the videos on the Durock membrane.

http://www.durocktilemembrane.com/?s_kwcid=TC|16363|durock membrane||S||3287352896

When tiling, the accepted method of installing the second sheet is to overlap the seams (i.e., not line them up), with the ends at 1/4-span between the joists, and NOT screw the second sheet to the joists, only to the first layer. the idea is to decouple (and provide strength). If you screwed the second layer to the joists, you've provided increased strength, but not the required decoupling. Also, if you glued the second layer and didn't get 100% coverage, you might have introduced some voids. The ply should be c-faces or better (i.e., no D) and use exposure 1 or exterior rated glue. So, in this case, I'd want to use a decoupling membrane (my preference is Ditra), or cbu on the floor. you can use the cheapest thinset to bed the cbu, as it is only there to provide 100% coverage, the screws or nails are what hold the cbu in place. In actual practice, the movement crushes the cbu around the fasteners over time, letting the whole cbu and tile sort of float. A decoupling membrane does a better job of this, and isn't as thick - is easier to install (no screws), and much lighter to carry and cut.

I like the Ditra and everyone else seems to as well so I will buy it and use it on the floor.

I mentioned earlier the walls around the tub are now covered with 1/2" Hardiebacker and the rest of the bathroom will be 1/2" greenboard sheetrock in a day or two. Should I use two different adhesives for the wall tile? OR is the thinset morter ok to set tile on both wall materials?

Use thinset! Thinset will work fine on both the cbu and the drywall and it's a lot less expensive than mastic (regardless of what it is labeled, if it comes premixed and in a bucket, it's technically mastic, and not thinset - thinset's strength comes from cement and there's none in mastic). Depending on the size of the tiles, mastic won't work as it needs to dry and it will take months through the small joints from the edge in. Plus, as noted, if you ever get it wet, it will re-emulsify. I've taken stuff fully dried that was months old and washed it off. Took a little scrubbing, but it got soft and came off. That won't happen with thinset!

Read the installation instructions on Ditra. It requires a modified thinset to hold it down to the plywood, and then unmodified to hold the tile down. The easier way to do this is to buy the unmodified (dryset) thinset at Lowes, and for underneath, use their add-in admix (modifier) rather than the water. Then, when done and setting the tile, just mix it with water instead...same stuff, two different uses based on what you mix it with. An alternative is to use Ditraset, which Schluter has made specifically to their specifications. You don't want the cheapest dryset thinset...they have the absolute minimum amount of cement in them. HD only carries a really cheap dryset, but Lowes (and any good tile store) will have others. If you want to buy the dry thinset with the modifiers mixed in, HD's Versabond is decent. When mixing a dry modified thinset, it is essential to follow the directions and remix after waiting the full slaking time. WHen you first mix it, you wet the modifiers. It takes awhile for them to absorb the moisture. That happens during the slaking period, then you mix it again which now coats all of the cement particles. Don't do this, and it's nowhere near as strong, nor does it spread as nice. When mixing the thinset to bed the Ditra, it needs to be smooth and able to hold a notch, but you don't want it stiff and dry. After setting the Ditra in the thinset, you should be able to pull up a corner and see that all of the mesh is covered. If not, then you probably didn't either mix it well enough, or it's too stiff.