How to repair waterproofing on old shower?

sydfoilist

Hi,

I have an old shower in our laundry room and the sealant and paint on the floor are deteriorating and flaking off.

We only moved in a year ago so I have no idea what the original products were but it’s likely from quite a while ago(!)

It looks like paint with some sort of thick clear glossy finish, presumably waterproofing. 
Would the right thing to do be to chip/sand back the deteriorated patches on the floor and paint new sealant on? Are there suitable sealants?

  

MitchellMc

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

Waterproofing, as defined in the construction code, is a protective layer that sits beneath tiles to create a watertight barrier and prevent moisture from seeping into the structure. It’s not intended to act as a finishing layer on top of a cement floor. In your case, there may or may not be a waterproofing layer beneath the existing surface. If there isn’t, the current installation doesn’t meet modern construction standards.

It appears that a rudimentary waterproofing solution has been implemented many years ago. Unfortunately, even if you remove the deteriorated surface, I’m not aware of any waterproof coatings that could be applied directly to the cement floor and serve as both a watertight barrier and a finished surface.

To bring your shower up to current standards, the best approach would be to strip back the existing layers to the cement base and walls, apply a proper waterproofing membrane, and then tile over the floor and walls. This would ensure the shower is fully compliant with modern codes and properly protected against leaks.

Be aware that due to the age of the shower, there's a reasonable chance that lead-based paints were used, so please wear adequate PPE and utilise methods such as wet sanding and chemical strippers to remove the current coating.

Please let me know if you have any questions.

Mitchell