Washers or Just Screws?

[dannyeverton]

You need washers for any mechanical fixings with those type of board. 6mm needs to be stuck with a solid bed of tile adhesive. Only really suitable for overboarding a skimmed wall or alike. Thicker boards can be dot and dabbed then fixings through the dots and the dabs!

 

[dannyeverton]

I have an uneven brick wall and also clinker block wall. I want to use 12mm jakoboard. Jako recommend 20mm if I dot and dab and screws. Can I scratch coat first with tile adhesive or bonding coat, let it dry, then a full bed of tile adhesive and the 12mm board on and screw? Thanks

 

[benchwarmer]

No! 20mm will barely tickle the brick?
12mm jacko +
Dot and dab =
At least 40/50 mm screws!
Minimum mate