Waterproofed walls aren't straight, how to fix for shower wall panel installation?

coldcountrycouple

Hi All,

We've waterpoofed our ensuite bathroom with crommelin. We are ready to install shower tray and Eśtilo shower wall panels. As it's an old house we have discovered walls aren't plumb and need to rectify this before we can complete the shower install. We have an up to 19mm gap, we brought some brutus moulding trim 38mm x 6mm.

Our plan is to place this vertically on wall using crommelin sealant adhesive then attach titan plastic packers to bring out to level. We are thinking of applying expanding foam in between then cutting foam level once cured and applying the shower wall.

First time doing a bathroom & looking for advice if this idea will work ? Other suggestions welcome, Thank you

MitchellMc

Welcome to the Bunnings Workshop community @coldcountrycouple. It's wonderful to have you join us and many thanks for your question on installing wet-area panels.

That’s a tricky one. Unfortunately, having a flat and plumb surface is pretty important for those shower wall panels to work properly. The only exception would be a slight deviation that the adhesive thickness alone would accomodate.

From the installation guide, the panels need to be fully adhered to a continuous, flat substrate so they can be pressed tight and any air pockets expelled. If you batten the wall out and introduce gaps (even if you fill them with foam), you won’t be able to achieve full contact. The panel itself isn’t designed to span or act structurally. It’s just a finish layer, so you’d be relying on it in a way it’s not intended to perform.

While your idea could work in theory, it does go against the installation requirements, which increases the risk of issues like poor adhesion, movement, or even the panel bowing over time.

A more reliable approach would be to:

• Pack and straighten the wall framing properly, or
• Install a flat sheet substrate (like villaboard or similar) that is shimmed/packed out to achieve a true, flat surface before waterproofing

That way, you’re giving the panels exactly what they’re designed to be installed onto.

It’s a bit more work upfront, but it will give you a much better long-term result and avoid potential failures down the track.

Please let me know if you have any questions.

Mitchell