How to use a trowel on top of a tanking membrane

[aenaos]

Hi everyone, I'm a DIYer with a week's training how to tile. I am about to tile my shower. I plan to use a tanking kit first such as the MAPEI one. My question however is, would the trowel scratch the surface of the cured membrane, causing a breach and negating any waterproofing done?

 

[Tiberiu]

Don't worry about scratching the waterproofing paint. Just don't apply to much pressure when you trowel the adhesive. The paint is strong enough to withstand the normal trowel pressure.