HELP! How do I tank 'this'?

[Toastandjam]

Hi - I know, I know - the plumber has sinstalled it too close to the wall, and why the builder felt the need to plaster the shower walls - we'll nver know.

Meanwhile, I'm about to start tiling 'it'

1. Please can someone tell me how I should tank around the mixer - should the holes/gaps be filled first with plaster?

2. Is the primer in my Mapei tanking kit enough?! It says it covers 4m2 but I can see (before opening it) that the container isn't even half full - doesn't seem to be very much....

Thanks

 

[yorksbuilder]

Please advise what is behind the plaster?

 

[Toastandjam]

Please advise what is behind the plaster?

it's a stud wall - you can just make out the joist at the bottom....

 

[accelerator]

There are some guidelines on the technical datasheet here:

SHOWER WATERPROOFING KIT

Provides an essential waterproofing system compatible with today’s frequently used showers

www.mapei.com

 

[opps]

I don't see why Mapei would ship such a small quantity in such a large container. Are you sure that someone hasn't previously opened it?

BTW, plaster skim over boards has a lower weight bearing than no plaster over the boards.

 

[yorksbuilder]

it's a stud wall - you can just make out the joist at the bottom....

Yes, I mean what's the plaster onto?
Regular plasterboard?
Moisture resistant plasterboard?
Cement backer board?

 

[simplesteve]

1. You can fill around the mixer with anything, as long as you get it reasonably flat with the rest of the plaster. I usually just use Tile Adhesive.
2. Unfortunately, you're not going to get far with that amount of primer

 

[yorksbuilder]

I have used the mapei tanking kit a few times for shower enclosures. The amount of primer they give is fine. Sometimes for large ones you need to buy extra roll of tape or 2 whole kits

You can fill the hole with tile adhesive and once dry prime and tank all areas

If it was my job, I would remove all the plasterboard and start again with backer board, seal around the valve properly with pu or polymer adhesive, then prime and tank the backer board

 

[catlad]

If it was my job, I would remove all the plasterboard and start again with backer board, seal around the valve properly with pu or polymer adhesive, then prime and tank the backer board

Me too!

 

[simplesteve]

I'd also check the depth of the tails from the feeds into that mixer. It's hard to tell from that photo, but is there room behind the mixer for a tile ?

In a perfect world, the job would be done differently, but to be honest there's no need to panic just because it's plastered. Here in the real world, id say 75% of the bathrooms i do are either onto plaster or plasterboard, and half of them don't get tanked first ! You'll be fine.

 

[Koolpc]

I agree, no need to rip it all off. Just tank it properly and tile. Should be fine.