I'm tiling 300X300mm ceramic floor tiles onto fibre cement sheeting. The tile adhesive suggests a 15sqm coverage for a 20 litre tub using a 6mm trowel.
I'm using a 10mm trowell and also buttering the back of the tile before fixing.
what sort of adhesive are you using?
generally only need an 8mm trowel. trowel a sample area, stick a tile down and then pull it off. If you're not getting 80% coverage, then you need to use more. but it sounds like you are putting it on much too thick.
yep too thick - I use 10mm trolwel at 45o angle across floor, place tile down, give it a push and a wiggle to set it in - a 15kg bag of x56 gets me about 12m ^2 . More isnt better, juts more expensive.
Tile Adhesive - Coverage 
