Will floor levelling compound stick to Dunlop Waterproofing?

[Lburton67]

Hi everyone,

I am installing a replacement bath and as they are different sizes I now need to apply a floor leveller before installing the replacement bath.   BUT, the floor has previously been waterproofed.    

Can I apply the floor leveller on top of the waterproofing (and then REPROOF)?

Thanks

LB

[MitchellMc]

Welcome to the Bunnings Workshop community @Lburton67. It's terrific to have you join us, and many thanks for your question about waterproofing.

Is the waterproofing intact? If so, there's no specific need to re-waterproof. However, you will run into the issue that self-levellers are designed to go over concrete surfaces and not a waterproofing membrane. They need porous concrete and associated primer to adhere correctly. So, according to our manufacturers, you'd need to remove the existing membrane, level the area and then re-waterproof. The issue with that is that you can't just remove a small area of waterproofing and then patch it; it needs to be one homogeneous layer over the entire bathroom floor and up the walls.

I suggest enlisting a qualified waterproofer's services to provide advice on the best way forward, as compromising the current waterproofing could prove to be a costly experience if all the tiles need to come off to repair it.

Please let me know if you have any questions.

Mitchell