My 1st Job Aquadefense over screws

[monkjack]

Silly question perhaps, but when you're applying a liquid membrane (aquadefense in this case), do you just apply it over the screws that were used to fix the boards. Or do you cover the screws in a little tape or something?

Also, when you've finished the tiling and grouting, and say you're drilling through the boards to attach the shower head fitting, won't that break the waterproof membrane? Or is it just a case of it's such a tiny hole how much water can get through?

 

[One Day]

Hi, Aquadefense will normally shrink on drying so it's probably a good idea to put a bit of scrim tape over the screw heads.
As for screwing through, yes it will compromise the waterproofing. To be 100% I will squirt a blob of wedi 610 or kerdi-fix into the hole before inserting the plug. If really stuck I'll admit to using Silicon!

 

[monkjack]

Thanks for the quick reply. I'll order some wedi 610. What do you use to attach the mapei tape by the way, I know it's not self adhesive.

 

[One Day]

The corner tape Mapei supply has mesh edges. Just push it into the corners whilst the aqua defense is still wet and make sure it's well bedded so the mesh gets completely covered. Because it air dries, it needs the mesh to make a bond.
I gently lay it into the corners and then use a 2" wallpaper scraper or a seam roller (NOT sTeam roller!) spread it into position.
If you were to use a waterproof tape like Wedi or kerdi, it would take months to dry out - if ever!

 

[monkjack]

I guess what I'm asking is, do you just use the aquadefense to adhere the tape in the first place and then second coat - I had originally assumed you put the tape on first using some kind of adhesive/whatever and then did two coats of aqua over that.

 

[monkjack]

I think this mapei video answers my questions.

Not sure what the difference is between aquadefense and mapegum, both by mapei. The spec sheet indicates aqua is a bit more heavy duty.

 

[One Day]

I rarely use it tbh.
I much prefer Ardex wpc and BAL tank-it (not from Topps though) as they don't rely on air drying.

 

[Flintstone]

I personally don't think that what he is doing in the video is going to make Much of a seal to the tray.

 

[monkjack]

I'm in no rush, the bathroom has been a building site for 2 months, I figure I can wait until next weekend for it to dry 🙂