shower tiling
 

Hi there
I have built a shower stall with 19mm wbp plywwod and have tiled it
with 10"x8" tiles.
I have two questions should I use grout or silicon in the corners
where the tiles meet?
and should I use an admix additive to the grout or seal the grout
after it is up ( the grout is water resistant) the stall has three
tiled walls and hinged door? I have used silicon between the tile and
the shower tray?