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There are damages to the timber flooring & garage plasterboard ceiling, which relate to a failed waterproofing membrane under the tile bed within the shower recess of the first floor ensuite. What needs to be done in order for this to be fixed. Thank you
Welcome to the Bunnings Workshop community @kris888. It's a pleasure to have you join us, and many thanks for your question about waterproofing membranes.
To properly address a failed waterproofing membrane, there are a few key steps that typically need to be taken:
First, the shower area needs to be fully stripped back. That means removing the tiles, screed (tile bed), and any underlying materials until the substrate (usually concrete or fibre cement sheeting) is exposed. This is essential because the existing waterproofing system has failed, and patching over it isn't considered a compliant or long-lasting fix.
Once stripped, a qualified waterproofer should be engaged to reapply a new waterproofing membrane that meets Australian Standards (AS 3740). In most states, this must legally be done by a licensed tradesperson, and a waterproofing certificate is typically required for compliance and for future insurance claims.
After the membrane is installed and cured, the area can be re-screeded and re-tiled. At this point, any plumbing should be pressure-tested to rule out contributing leaks.
In terms of damage to the flooring and garage ceiling—these areas will need to be assessed and repaired once the shower is fixed. That might involve replacing water-damaged timber flooring or underlay, and cutting out and replacing sections of plasterboard in the garage, followed by painting.
Please let me know if you have any questions.
Mitchell
