Adhesion/coverage problem

[LEH]

Jackoboards

 

[LM]

Judging by your pics the adhesive looks like it’s dehydrated too quickly on the back of the very absorbent tiles, mix probably too stiff also. As above, what substrate where you tiling to and did you prime it?

 

[Blunt Tool]

Adhesive could be too dry and that biscuit backed ceramic tiles draw the water from the adhesive quickly, sponge the back of them with water before serrating with adhesive and wash down the jackboards aswell with water

 

[LEH]

Thanks for all the pointers

 

[Dumbo]

To be honest I always prime backer boards because it save damping them down . Once they are primed it's done .

 

[Unused Account 1]

Ive done it just make sure addy bit wetter