Charles' Shower Project

[Davy]

When you nail your lath along the top, it's not going to hug the wall like you'll need for it to do. I would apply my scratch coat as thin as possible and then place some bricks or anything heavy against it along the bottom to push it back as much as you can. I have a feeling you'll be hurting for space.

Yep, I know the old school way, Charles. It was done that way before thinset was invented. The best thing to do is to do the mud work, let it set and then use thinset.

[Davy]

Actually, the tiles weren't beat right into the wet mud, Pure was used first.

[princecharles]

Dave, the old mud sticks out about 1 1/8 inches or more past the blocking there is plenty of room in there as shown in the picture.
The wire lath that I put up will be the equivalent of putting up a piece of dura rock.

I thought of setting up screeds for a plumb coat of mortar over the scratch coat and then using thinset to set the tile but because of the variations in the wire lath scratch coat of the existing wall and that the max thickness of thin set should not exceed 3/16" I decided that it would be more accurate to do it the old fashion way.

setting the tile the old way is another area where the moisture content of the mortar is critical to bond. Its like laying brick, If the mortar is too dry you get a poor bond if the mortar is to wet it is too soft and makes it hard to set the tile. The best thing to do is to soak the tile as you would if you were laying brick so you can make a stiffer mortar and the mortar should have a good amount of lime in it.

[Davy]

Looking at your pics, it's hard to tell the room you have. With 1 1/8, that'll be plenty room. Sounds like you have it figured out.

[princecharles]

The thing I have to get right is the deck mud!
I know there is a range between too dry and too wet. What are the consequences of having the mud too wet?

[princecharles]

this picture shows more clearly how thick the bedding mortar is all around

[Davy]

I can clearly see the mud thickness on the outside. But, the mud thickness can vary from wall to wall inside the shower depending on how much mud was needed to plumb it up. Along the bottom, one wall might be 1 1/4 and the next 5/8. You never know until you check it.

I would still advise you to scratch coat the walls and let it set. Then apply the finish coat flush with the old mud. You can do this by embedding 2 short lattice sticks in the mud on each wall, making sure they are plumb. Make these sticks flush with the old mud. Once your finish coat is flat and plumb then let it set. Then use thinset.

The scratch coat needs to set up. It does no good to apply the finish coat over a fresh scratch. With it being 1 1/8 thick, you'll need a scratch coat, which is a good thing. The scratch will help set up your finish coat.

[princecharles]

Its pretty much the same thickness inside the shower. However the old tile is about 1/16 thicker then the new tile. thanks again for your advice

[princecharles]

This is one for the experts. I am replacing a shower pan that was constructed in 1936; I have attached pictures. I need to know the recipe of the mortar used to SET the tile in a Shower. Each tile appears to have been buttered with mortar and pressed against a scratch coat of very hard mortar(dark gray). As you can see from the pictures the thickness of the tile setting mortar behind each tile is approximately 1 to 1 1/4 inch thick and is very white in color. It looks to me like the mortar has a great deal of lime in it or is just lime and sand. Does any body know the recipe for this mortar?

[Davy]

I mix my wall mud (fat mud) 4 sand to 1 portland cement and 1 Lime. I wouldn't try to butter out each tile that thick. I would, apply a scratch coat and let it set. Then apply the smooth finish mud bed over it (brown coat). Hold that mud bed back so the tiles will finish out flush with your old tiles. Stick your tiles with thinset mortar.

When you fasten your lath, keep the nails up high to avoid ruining the pan. Then scratch it and lean bricks or anything else heavy against the bottom to hold the lath tight to the walls.