Waterproofing a bathroom

[dustycooks73]

G'day I'm confused as!

I've had to redo my bathroom from scratch.

I've pulled up the tiles and screed all the way to the cement slab. I had someone re screed for me cos it would be a dogs breakfast if I did it!

Anyway, on all the posts and vids I've seen some use a plastic sheet in conjunction with the paintable membrane and some don't, the one consistent is it must be super clean and free of dust etc. the screed that has been laid is slightly gritty, I haven't washed it down yet. the Q is will that effect the W/P solution? an duo I need to use the plastic sheet?

cheers D

[Jason]

Hi @dustycooks73,

Welcome to Workshop. 

Sorry to hear you've hit a roadblock with your bathroom renovation, but let me tag some helpful members in @ProjectPete, @gippslandhome, @PJA and @Adam_W to see if they'd like to kick off the discussion and share their thoughts about next steps for you.

Feel free to post anytime you need a hand with this project or any others around the house and garden. 

Jason

[MitchellMc · Accepted solution]

Hi @dustycooks73. Apologies for my slow reply.

Before you start the project, you may like to check with your local council about any licensing requirements for water-proofing.

If the surface is slightly gritty, I would recommend using Gripset Betta Prep Coat Waterproofing Primer before applying the Gripset Betta- Under Tile Waterproofing Membrane. This primer will ensure the membrane adheres correctly to the surface.

There are also some helpful all-inclusive products for shower recesses like the Crommelin Shower Waterproofing Kit. The kit provides all materials and instructions to successfully waterproof a shower recess prior to tiling.

I'll pop a couple of videos below which should also give you plenty of information to assist you.

Please feel free to let me know if there is anything further you need.

Mitchell

[Carmel99]

Hi...we've just finished our bathroom and did HEAPS of research into waterproofing. We used the paint on waterproofing... Once the screed has fully dried, vacuum it well and paint over some primer (use one that is compatible and same brand as the waterproofing ) then pain on the waterproofing. I used 3 coats in the shower and 2 coats on the rest of the floor. You need to silicone the edges first and use waterproofing tape around the edges. Bunnings have heaps of great videos that go through the steps. Also dont forget to seal the grout afterwards as it does make a big difference to how clean the new tiles stay (:

Good luck ! 

[dejayajay]

Those plastic sheet videos are all US based. That method is not used here, at least not on any job I have ever seen. 

Vacuum any dust, and prime with an acrylic based concrete primer (not a paint primer). Apply extra to areas that are soaking it in too fast.

(My advice is DON'T use Bondcrete, as it is dissolves back to a liquid if it gets wet - I think it is just PVA glue, with an genius brand name).

Then paint on the waterproofing, two to three coats, or enough to make a waterproof membrane. And like another person here said, apply a fillet of compatible sealant to all corners and crevices beforehand. Use your finger to smooth it to a small radius, 5 - 6 mm. I'm not sure if silicone is right for this. I use an SMP eurethane such as Solarflex ($21/600ml sausage), but you can use Flexiseal ($15/600ml). (Both are paintable, but the SMP has the edge in sticking to the widest range of products. I use it for many, many tasks).