How to re-waterproof over screed?

[jjjbbb]

Hi, 

I am renovating my bathroom. I have removed all the old tiles and have reached the screed. It is in decent condition I think. My questions are: 

- Can I re-waterproof over the exisiting screed? I really don't want to have to remove and re-screed as that seems like a lot of work. 

- The walls are quite uneven, with chunks missing out of the render. What can I use to even them out to provide a nice surface for the waterproofing? 

Thanks!

  

[JacobZ]

Hi @jjjbbb,

Welcome to the Bunnings Workshop community, it is fantastic to have you with us.

As long as the screed is solid and not flaking away, then you are fine to waterproof over it before putting down tiles. You can use a product such as the Crommelin Shower Waterproofing Membrane over the screed.

To repair the uneven walls, you can apply Dunlop Multipurpose Acrylic Render before waterproofing and tiling over it. Make sure you give the wall a good clean with a wire brush to remove any loose material, then wash it down with clean water to remove any dust that can affect adhesion. Check out How To Render for some guidance on the process.

It might look a bit messy, but you are not far off from waterproofing and then tiling.

Let me know if you have any further questions.

Jacob

[JacobZ]

Hi @jjjbbb,

I should also mention that due to the licensed nature of the waterproofing industry, you will have to get in touch with a professional waterproofing contractor to ensure your waterproofing is done to the relevant Australian or New Zealand Standard for waterproofing.

This will ensure your waterproofing is done to a professional standard and is covered by your Waterproofer's warranty.

Jacob