What grout for balcony tiles?

Question

Hi,

I have a 1×6 m balcony that stays mostly wet during the Melbourne winter. I’m having the tiles and underlay redone because the original tiles and grout cracked, which caused water damage.

I want to make sure this is done properly. When I spoke to the tiler, he mentioned he would be using standard grout typically used in bathrooms. That didn’t sound quite right to me.

Isn’t regular grout porous? If water pools on it, even slightly, wouldn’t moisture eventually seep through? I’ve been reading about it, and it seems like epoxy grout might be a better option.

I’d appreciate some advice. My main goal is achieving the best possible waterproofing and long-term protection.

MitchellMc · Answer

Hi @jesinj22,

Cement-based grouts, such as the grout used in your shower, are perfectly suitable for use on a balcony. While cement grout is porous and allows a small amount of moisture to pass through, a correctly installed tiled balcony should have a waterproofing membrane beneath the tiles. This membrane is designed to capture any water that seeps through the grout and, more importantly, prevent moisture from causing damage if water finds its way through tile joints or future cracks.

From what you've described, it sounds possible that the issue you've experienced may be related to a failure or absence of the waterproofing membrane, as a properly functioning membrane should prevent water from causing damage to the underlying structure.

Although epoxy grout offers greater water resistance and can reduce moisture penetration, it is not a substitute for a waterproofing system. Regardless of the grout type used, a balcony should always have an effective waterproofing membrane installed beneath the tiled surface.

Given your concerns, I'd recommend consulting a waterproofing or tiling specialist to assess the condition of the existing membrane and determine whether it may be contributing to the problem.

Please let me know if you have any questions.

Mitchell

EricL · Answer

Hello @jesinj22

Yes, some Davco grouts are suitable for swimming pools, but you must check the specific product type, as it does not apply to all of their grouts. The best options include the Davco Sanitized Colorgrout it's a cement-based grout suitable for submerged applications like pools and spas. However, it is crucial that you must mix it with the Davco 4 in 1 Grout Additive for pool use, instead of using water to increase its water resistance and flexibility. It also has a very long cure time of 21 days or longer if the weather is overcast.

Whereas the

https://www.bunnings.com.au/dunlop-3-25kg-slate-grey-easy-clean-epoxy-grout-kit_p6650311

only takes 7 full days to cure. Because it is an epoxy-based formula, it creates a non-porous barrier that prevents water from seeping through. It naturally resists stains, chemicals, and the growth of mould and bacteria, making it ideal for indoor and outdoor wet areas like showers, bathrooms, and laundries.

If you need further assistance, please let us know.

Eric

jesinj22 · Answer

Thanks @EricL .

I am a bit confused.  I am looking at this  Davco 1.5kg #03 Gunmetal Grey Sanitized® Colourgrout , and the description says

"Commercial and domestic walls and floors including swimming pools and wet areas"

Isn’t this a normal type of grout? How can it be used for swimming pools? If it can be used for swimming pools, then wet balconies should definitely be fine, shouldn’t they?