Pablo's master bath re-do
 

I'm helping a friend re-do their master bath.

We've already poured the pre-slope and pan. All's good there.

Getting ready to build a custom niche. This will be my first try at a non-store-bought niche.

The plan is CBU, taped seams, thin-set and red guard (alot of it).

Still a little nervous about building my own niche but youz guyz seem to like 'em that way.

Anyway, the niche will be in a 2x4 wall adjacent to a bedroom. Not much room for depth. I'm wondering the best way frame this out - namely the BACK of the niche. I'm considering fastening the CBU on the back of the niche to the existing wall board. It's a '50s house with wall board (not drywall) under a scratch coat and veneer plaster. Pretty tough stuff. Wondering if this plan would be kosher and/or the best way to attach the CBU if I go this route??

Any ideas??

Hi Eric,

Yeah, go ahead and use construction adhesive to apply the cement board to the back side of the wall board. Use 1/4" thick stuff if you wanna squeeze out a tiny bit more depth from the niche. Attach the cement board on the jambs with fasteners.

Can I ask what cement board you're planning on using? If it's Hardibacker, I'd recommend thinning down the RedGard to make a primer for the first coat. Hardi is so dense that the primer will aid in adhesion.

:)

I'm a bit concerned about my shower pan finish.
 

The pan is a bit "loose" on the top in some points. I used The Tile Shop's pre-made "floor mix"

It was mixed as per recommended "wet sand" and packed in to place. It was mixed thouroughly with my heavy duty Husky mixer (see below)

When I finishe placing the pan, I used a wet sponge over the pan and added a little water to trowel. THe spots that are the hardest are the spots I though I might have used TOO much water Those spots are hard like normal concrete I'm used to (I've done a few pans with regular sacrete concrete).

I've seen some discuscion on this in the past. I know the mud pans aren't supposed to be rock hard on the finish like regular concrete. Are they?

The "loosenes" I am seeing is from walking on it (finishing CBU etc.) and seeing some sand knocked loose that needs to be vacuumed up. It's not crumbling but I can get some sand up with a fingernail. I accidently droped my cordless drill yesterday and it bounced. No dents or marks in the pan.

How "loose" is too loose?

From the way you describe it, it sounds fine. There will be a little sandiness on top. If it's hard and you can't make a pit in it by rubbing with your finger you should be good to go. If you can vacuum it up all the way to the bottom, then you have a problem (like my first attempt).

What Wendy said. Its supposed to absorb and shed water easily. With some effort you should be able to dig through it with a screwdriver.

I would "knock" on it and see if any of it sounds hollow.

Also, is it just the camera lens that makes it look like the cbu walls bow in?

Already knocked on it and it sounded solid.
 

It must be the camera angle. Those walls are dead flat.

Pouring SLC tomorrow and have a question.
 

Using Level Quick RS. Over plywood, Sun Touch heat mat and some plastic lath left over from a previous friend's job. The plan is the half inch required for plywood substrate.

Diluted 50/50 Level Quick Primer first coat is applied per manufacturer's recommendation for plywood.

Directions don't say anything about a second coat of primer. I seem to remember doing two coats on mine (plywood) a couple years ago. TileguyTodd in the liberry says two coats and a spray over the mats/lath (great idea, btw).

Should I do a second coat before setting the mat/lath? Or just stick with the 50/50 diluted single coat. Is two better than one?