diy bathroom...from the ground up.

[mcubed]

I'm currently diving into a bathroom renovation, and we're at the point where all miscellaneous products, materials, etc. need to be nailed down. First things first - the floor.

We're in a 1912 house - the bathroom is largely demoed, mostly so we could see if we had any surprises. Thankfully, none so far. At this point, I'm assuming the joists are 2x8 (hardwood), 11' span, with a 3/4" diagonal plank subfloor. Technically okay by the deflectometer.

I just want to make sure we have the right plan, and finish nailing down/getting materials.

Right now we're planning to:

1. patch the subfloor if needed
2. screw/liquid nail down 1/2" ply
3. screw down 1/4" cement board over unmodified thinset (brands, anyone?)
4. install suntouch radiant floor (purchased)
5. pour mapei ultraplan easy self leveler over it (4 bags purchased off craigslist, 80 sf)
I know you should use 1/4" adhesive foam at edges for expansion, and I need a primer. I'm assuming primer t for absorbent concrete off of their table - is that correct? And where's the best place to get mapei products if there are any kansas citians out there?
6. lay tile: 18" porcelain in a diagonal pattern, 3/8" thick (purchased)
6a. Currently planning on using modified thinset - brand tbd, with a 1/4" square trowel. Is that too small with larger tiles? Or is okay since we'll have the leveled floor and fairly consistent tiles?
6b. leaning towards 3/16" grout joints - I prefer 1/8" but am new to diagonal tiling. Any diagonal/grout joint suggestions. Last time I tiled, we used 3'x6" planks with 1/16" grout - not planning on repeating that.
7. grout with sanded grout. brand advice?
8. seal - solvent based. brand advice?

How does that sound? Am I on the right track?

[Kman]

First of all, check those joists. Don't let an incorrect assumption cause a failure of the entire installation.

I'll try to answer the technical questions. The product questions I can answer if you have a particular brand name, otherwise you'll be restricted to what's available in your area. Sorry, I can't help with that part.

2. No liquid nails needed. Just use screws that go through the 1/2" ply and subfloor, but not the joists. 1 1/4" screws will work fine.

3. Use either modified or unmodified, whichever the manufacturer of your CBU recommends. Their respective website can guide you. Don't forget the mesh tape on the seams.

6a. You'll want to use at least a 3/8x1/4x1/4" trowel for tile that size, provided your floor is pretty flat. 1/4" would be too small. You can go up to 1/2" square, or 1/4x1/4x1/2" trowel, which is my preference. Same amount of thinset either way. You'll want to skim-coat the backs of every tile to achieve a good bond.

6b. I would recommend the 3/16" grout joint. With the variances in actual tile size, 1/8" could be too small and cause you some problems with getting everything straight.

Hope this limited info helps.

[mcubed]

We will - just have to finish up with the removal of stuff up above. It seems solid right now - doesn't look like much has moved in the last 100 years - but we'll see.

And thank you -

2. perfect. is liquid nails more for laying down an initial layer of subfloor? Or just non-tile areas?

3. check.

6a. I grabbed some trowels at a great sale - 1/4" square for other areas, 1/2" square for the big tiles.

6b. And we'll plan on the 3/16" grout joint.

The last floor question: Any advice on the best way to lay/cut tiles accurately for a diagonal floor?

I have the basic layout method - 3/4/5 triangle to get a right angle, draw parallels in both directions, and snap a 45 through the intersections to get the angle.

I'm thinking about the cutting of a smaller triangular piece at an edge - do you just measure along the two angled sides to get the size - or is there a better way to do it? Ie, using another tile to help measure...Or am I overthinking this?

Thanks for the advice.

[Kman]

Liquid nails or some equivalent is used to adhere the subfloor to the joists, but not between the subfloor and a layer of underlayment.

I have a hard time cutting porcelain tiles accurately with a snap cutter, so most of the time I use a wet saw for the cutting. The tile usually don't want to break along the score line, and I have to clean them up on the saw anyway. This is particularly true when cutting them on a diagonal, so I use the saw 100% of the time for that.

You have the right idea for your layout. Another way to do is to snap a line down the middle and line up the tiles to it with two opposite corners directly on the line. And when I'm cutting the triangular pieces, I measure along the two sides if it needs to be very accurate. For a piece where the cut edge will fall under the trim, I just measure from the corner to the wall, knock off about 3/8-1/2", and make the cut based on that measurement. The 1/2" you knock off will allow for the grout joint plus an expansion joint at the wall.

Others may have different methods for cutting those pieces.