Advice needed for bathroom project

[k.k.]

I'm also going to do ceramic subway tile 42" high wainscoting. I was planning on using 1/2" permabase cement board for this, even though it isn't in a wet area. Is this the right approach? above that, I was going to use a 1/2" moisture/mold resistant wall board.

[Mike2]

No need at all to use cement board on walls outside the shower. Kendrick, do it with wallboard out there.

[k.k.]

Any particular brands you recommend, Mike?

I assume I should still tape and thinset the joints?

[Mike2]

Wallboard's always been a commodity to me. Unlike trucks, never noticed any difference in brands. Do go Dodge, however.

Tape and finish the seams, then prime the compound before setting the tile. Pretty routine and boring, that.

[k.k.]

I just noticed that some of my radiator pipes running through the floor may touch the subfloor in where pipe fittings/couplings were used that raise the profile. Is this a major issue, it's near the wall where there will be no foot traffic, so my main concern is moisture/sweat (3/4" copper & black pipe). Should this be insulated or covered in any way?

[Mike2]

I'd help you if I could but don't know nothing about steam radiator piping.

Hmmm...Is there really copper and black iron pipe connected together, without dielectric/galvanic fittings?

[k.k.]

No, they don't connect to each other. The hot water feed is copper and then the return is black pipe.

[k.k.]

ok, i just put the 3/4" T&G ply in last night. I'm going to go over it with 3/8" titebonded and screwed.
One problem though: There is a section about 12 - 14" deep that I didn't pull up the 3/4" T&G floor boards because I would have had a really tough time installing blocking for plywood in that location.
so i tried putting a screw into a floorboard to see how it would hold and it split the board. Now i'm a little nervous about screwing the 3/8" ply to the floor boards. Is there a recommended glue for attaching the plywood with no screws?
2/3 of this section will be covered by the vanity cabinet and not tiled, so I'm not worried about that section. There will be a 1'x3' section where there will be tile.
Any suggestions?

- Kendrick

[ddmoit]

Hi Kendrick,

Pre-drill your screw holes to minimize splitting.

I'm not aware of any gluing method that does not also include fasteners. And, gluing incorrectly is worse than not gluing at all.

The difficulties you are having are the reason that 3/8" is the bare minimum requirement for a subfloor layer. Many don't like to use anything less than 1/2".

[bbcamp]

Pre-drill the screw holes, the boards won't split.

[k.k.]

Thanks for the advice Dan & Bob! I'll give it a try. Do you recommend that i put the titebond2 between the floor boards and the 3/8"?

[cx]

And iffa Injineer says the boards won't split, the boards had damn well better not split!

The 3/8ths ply isn't of sufficient thickness for use over the board flooring, anyway, Kendrick, half-inch being the minimum requirement for that application. But given the location you might get by with what you're planning.

I would not bother trying to glue to the board subflooring with the Titebond.

My opinion; worth price charged.

[k.k.]

ok, i layed the 3/8 over everything. Used titebond & screws for over the 3/4 ply and just drilled and screwed to the floorboards. Seems really sturdy so I'm not to concerned with the small area over the floor boards.

So now I have an anti-fracture membrane (ECB Membrane made by NAC products, recommended by tile mfg) to lay over the ply. But before i do that, i believe that I have to thinset and tape the joints of the 3/8" ply. So my question is: is there a pre-mixed latex modified thinset available for this? Or should I just use the thinset that the glass mosaic tile mfg provided me - Reflex modified. I figure i should have enough, 50lb bag and i'm only doing about 40sq ft. I just don't know how I would mix up such a small batch for the joints. THere is probably only 22 linear ft of joints.

- Kendrick

[cx]

Originally Posted by kk

But before i do that, i believe that I have to thinset and tape the joints of the 3/8" ply.

I think there is some confusion there, Kendrick. You do not wanna do that sorta thing to any of your plywood installation. Next time you use CBU, keep it in mind, though.

You do not wanna use any pre-mixed product in any phase of your floor tile installation.

My opinion; worth price charged.

[k.k.]

ok, i'll keep that in mind for next time..lol

is there anything that i need to put between the joints of the ply? i figured that there shouldn't be any gaps when I put down the membrane and since small glass mosaic is going over it, the joints could be more of an issue that with bigger tile.