How can i retile and waterproof an external balcony?

[damon99]

I have an outdoor teracota tiled balcony about 30 sqm.  Its leaking through to the area below which fortunately has a concrete floor with a drain, but still the wooden timbers under the balcony are starting to rot.  The wooden ballistrude is also rotten and needs replacing.  There's cracks in the grout, and under the tiles is concrete sheeting.

I had a tradie take a look an he said it probably was never properly water proofed, they just relied on the grouting to keep the water out.  So i need to pull up all the tiles and put down a membrane.

I'm here for any advice, but specifically should I use a liquid membrane or a sheet membrane for a job this size?

Cheers.

[Jason]

Hi @damon99,

Many thanks for your post and let me extend a warm welcome to Bunnings Workshop. We're pleased to have you join the community.

It's great you've got some professional advice as it sounds like a potentially dangerous situation. Let me tag a few helpful members in @Nailbag, @JDE and @Jewelleryrescue to see if they can kick off the discussion and share their thoughts.

Jason

[JacobZ]

Hi @damon99,

Welcome to the Bunnings Workshop community and thank you for your question.

As my colleague @Jason has mentioned, a rotting timber frame beneath the balcony is not a good sign and it should be assessed by a suitably qualified person such as a builder or engineer and rectified as soon as possible to prevent collapse. Once the frame has been deemed structurally sound by a suitably qualified person, you can look at the waterproofing on top.

Typically, balconies like yours will use an exterior-grade liquid membrane such as this Crommelin Exterior Grade Brushable Waterproofer. Other elements will need to be added such as joint flashings where the balcony meets the wall and a sufficient drip edge to ensure water doesn't flow back underneath the balcony on to the frame.

As waterproofing is a licenced industry with strict standards that should be followed, I'd suggest speaking with a licenced waterproofer for their assistance with this project.

Let me know if you have any further questions.

Jacob

[Nailbag]

Hi @damon99 

a few moths ago I had a request to repair a very similar job. The tiles were worse being lifted and split across the floor and at the posts. The water damage had extended through the wall cavities below making the situation very serious.

I had the same recommendation as your builder that the tiles will need to be lifted, the timber sub-frame replace as necessary, new fibre cement underlay installed and re-waterproofed. Then new tiles installed. I also recommended a registered builder perform the work that could provide a warranty as this will easily be a $6K+ project.

Nailbag