How to seal a leaking outdoor balcony?

Hi there

First time posting here.

So I have an outdoor tiled balcony that is not covered with a roof, and it is leaking through to the ceiling of the bedroom below. A lot of the grout above the leak is cracked, missing or has shrunk. I have been quoted $50,000-60,000 to completely renovate which is way out of my affordability. It’s about 15sqm in area. I’m reasonably handy around the house but have never done tiling, nor regrouting.

i assume if I want to try and fix the grout, removing the grout and regrouting with epoxy grout might be the way to go to get waterpoof seal.
Any thoughts? Really trying to avoid the full reno cost but also don’t just want to delay fixing the leak.

Cheers.

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Comments

MitchellMc

Welcome to the Bunnings Workshop community @joelt. It's terrific to have you join us, and many thanks for your question about sealing a leaking balcony.

The quote likely includes the removal of the tiles and re-establishing the waterproofing membrane, as that's what has failed. You could employ various methods, such as using epoxy grout, to try and seal the tiles from leaking, but the underlying issue is that the membrane is leaking. The membrane captures all the water that seeps through your cement-based grout and/or tiles and redirects it off the roof. The grout and tiles are not by nature designed to be waterproof.

You might have success replacing the existing grout with epoxy, but you'll still be left with a compromised membrane, and any leaks that get past your new re-grouting will continue to leak downstairs.

You could consider removing the tiles yourself, having a professional re-waterproof the area and then re-tiling yourself. There would be a bit of work involved, but that would leave you with a leak-free roof and cost substantially less than having a professional complete the project entirely.

Please let me know if you have any questions.

Mitchell

emmab1986

https://www.workshop.bunnings.com.au/discussion/comment/40261#Comment_40261

Hi Mitchell,

I have a couple of questions regarding my leaking balcony:

How long does a waterproofing membrane typically last?
Is it possible to apply the waterproofing layer ourselves?
Someone suggested using Gorilla Waterproof Patch & Seal to fix a leaking balcony, does that product actually work for this purpose?

thanks!

EricL

https://www.workshop.bunnings.com.au/discussion/comment/92142#Comment_92142

Hello @emmab1986

Outdoor waterproofing can last anywhere from 5 to 25 years, depending on the system's quality, materials, application, and environmental factors like weather and maintenance. Proper installation by a qualified professional is crucial, and regular maintenance can help extend its lifespan.

Can you apply the waterproofing yourself? Yes, but I don't recommend it. Council rules and regulations might require you to engage the services of a trained professional so that the waterproofing is installed to code and is covered under the installers warranty. Having a professional install the waterproofing also saves you from having to guess if the application was correct and no step was missed.

The Gorilla Waterproof Patch & Seal liquid sealer acts similarly to a rubber sealer and prevents water from passing through. Is it the right product to use for your particular repair job? It probably isn't because a liquid rubber sealer is different from a waterproofing membrane. The waterproofing membrane can be tiled over and is more robust than a sealer. It can cover a large area and keeps its consistency uniform.

If you need further assistance, please let us know.

Eric

emmab1986

https://www.workshop.bunnings.com.au/discussion/comment/112125#Comment_112125

Thanks, Eric.

Our balcony waterproofing was redone about six years ago. If the waterproofing is still in good condition, should there be any leaking at all? I’ve also noticed some cracks in the silicone. The area where the leak was observed is at the lowest point of the balcony, where water tends to pool, and that’s also where the silicone cracks are visible. I’ll take photos and send them through when I’m home.

thanks, Emma

MitchellMc

https://www.workshop.bunnings.com.au/discussion/comment/123569#Comment_123569

Hi @emmab1986,

If the waterproofing layer was installed correctly, then there should be no leaks at all. It captures all water that passes through the tiles and grout, and this is especially important if there are cracks in the grout. If you are getting water leaks, then either the membrane has failed or the water is managing to bypass it somehow.

Regarding pooling, this indicates that the balcony was not graded correctly, as water should not pool on the surface. It should run freely to a drain and evacuate the area. If there are visible cracks in the grout or silicone where water is pooling, repairing those would help stem the leak; however, it doesn't address the underlying reason why the membrane is not working correctly.

Mitchell

emmab1986

https://www.workshop.bunnings.com.au/discussion/comment/131086#Comment_131086

Hi Mitchell,

I completely agree that the balcony wasn’t graded correctly. We did notify them at the time they redid the balcony; the slope improved, but it’s still not good enough. After it rains, we still have to wipe the water off for it to dry.

Attached are a couple of photos of the grout. Do you think the grout needs to be replaced?

Crack grout_1.jpg Crack grout_2.jpg

MitchellMc

https://www.workshop.bunnings.com.au/discussion/comment/135715#Comment_135715

Hi @emmab1986,

From the photos, the grout itself between the tiles looks generally fine and probably doesn’t need replacing if there are no visible cracks. The main problem is actually the joint between the floor tiles and the wall tiles. It looks like the existing silicone or polyurethane seal has lifted and delaminated, leaving a gap where water can easily seep underneath.

The best approach is to remove all the old, failing sealant, thoroughly clean the tile surfaces in that joint so they’re completely free of residue, and then reseal using a high-quality flexible sealant like Sikaflex 11 FC. Apply it carefully from the floor tiles up to the wall tiles to create a continuous, watertight barrier. This should prevent water from penetrating under the tiles and help address the leaking issue.

Mitchell

emmab1986

https://www.workshop.bunnings.com.au/discussion/comment/138852#Comment_138852

Hi Mitchell,

Thanks for the details. This is really helpful! I’ll do as you instructed.

Emma

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