Hi I'm fixing 10cm x 20cm ceramic tiles to Jackoboard in a tanked shower area would be grateful for a recommendation on the ideal trowel notch size and a slow setting adhesive - preferably one that is availble from CTD.
The smaller notch, the better. Less adhesive, better grip. But anyway depoends on the support. I think a tanked area would have rounded corners, so a bit bigger notch will be needed to save the deflections. 6-8 mm. At CTD you can find at least 3-4 ready mixed adhesive for this.
If its a tanked shower.....you really need to use a cement based adhesive. Also, most ready mixed adhesives can't be used at depths over 3-4mm.....cement based will let you level out any imperfections in the walls. CTD do a brand called ultra trade with various setting times in either grey or white....depending on what colour grout you're using. I use this brand a lot for walls and find it a good adhesive at a very good price. Use a 5-6mm notched trowel and you can backbutter the tiles if you want to....esspecially if they are porcelain or heavily patterned.