If you are lining up your grout lines rather than installing them diagonally you can then draw lines on your ceiling as guides to where your tiles should be.
Installing marble tile on ceiling.
To install cement board spread thin set adhesive over the wood subfloor using a 1 4 inch notched trowel.
Place your marble tile on the mortar.
Using this starting point spread the mortar and use a trowel to notch it.
Cement board also is engineered to bond very well with thin set mortar adhesive which you will use to install your marble tile.
No need to do the bead around the edge or anything else.
When installing tile overhead make sure the substrate is solid and stiff and that it provides a good bond.
Although many showers only have tile running up the wall until around the 7 foot mark above the shower head some showers continue all the way up.
Mix up the thinset according to the manufactures specifications.
If you are applying mortar over seams in the floorboard apply mesh tape to the seams to avoid cracking.
Working on the ceiling is hard enough without worrying about whether you re keeping your layout square and parallel.
If you re installing tile on the ceiling above a fiberglass or acrylic tub you ll want to use some wood or cardboard to protect it in case of a falling tile.
I d like to extend marble wall tiles up to and across the ceiling of a walk in shower.
I plan to apply a kerdi decoupling membrane over 1 2 in.
When installing tile on the ceiling you want to install the tile on the shower walls all the way up to the last row before the ceiling as i ve done in these photos.
After putting each marble tile on the mortar place a 1 16 inch tile spacer between it and the next tile.
Continue the installation process with the second course of tiles by applying vertical grooved mastic above the first course slightly wider than the tile.
Lay the cement board sheets into the thin set and fasten them to the subflooring with 1 1 4 inch cement board.
How to install granite tile on a shower ceiling.
Try using one of the non sag thinsets like laticrete s 255 or mapei s ultralite.