How to remove and regrout outdoor balcony and mortar mix?

[leoantw]

SAME TILESSAME TILES

[MitchellMc]

Welcome to the Bunnings Workshop community @leoantw. It's wonderful to have you join us, and many thanks for your question about removing grout and re-grouting.

How large is this area? Even for the pictured area, removing the grout would be quite an extensive, painstaking and time-consuming process. You'd likely need to use a larger tool like an angle grinder and a smaller oscillating tool for the finer work. Given the amount of work it would require to remove the existing grout, it would be best to consider replacing the tiles entirely. The process of removing the grout would be so difficult I don't believe you'd find a professional that would consider it unless the damage is localised to a small area and I certainly would be hesitant to give it a go as a D.I.Y. project.

The current grout is sunken below the surface of the tiles in this area, so you could potentially remove any loose material and grout over the existing grout. This wouldn't be the preferred method, but it could refresh the look for several years. That's not a bad idea if you were potentially considering replacing the tiles in the future.

Please let me know if you have any questions.

Mitchell
 

[leoantw]

Hi Mitchell,

Many thanks, your response is greatly appreciated.

The total area is about 26 sq metres but not all in need of repair. The mainly extended eve covered areas are pretty good. My biggest problem is the rain is penetrating the damaged areas, dripping down inside and causing paint to bubble and peel on the exterior wall.

Looks filthy!!

I know it would be difficult to get a tradie to do a fiddly job and I don't want to do a re tile at this point. I am thinking of angle grinding the very damaged areas to a depth of 5-10 mm approxand re mortaring. What mix ratio/type mortar should I use?

Also is there a clear sealant I could use in slightly damaged areas just to waterproof.

Any/ all suggestions on tools/ tips etc would be greatly appreciated.

Thanks

Leo

[MitchellMc]

It's worth remembering, @leoantw, that your balcony should have a waterproofing layer beneath the tiles. If water is dripping through, then it sounds like that layer has already been compromised. The grout between the tiles isn't actually waterproof and still lets water weep through; that's why we install waterproofing membranes in showers and under balcony tiles. The reason for mentioning this is you don't want to cut so deep with the angle grinder that you destroy the membrane if there is one in place. I wouldn't suggest cutting deeper than the tile's thickness. 

I'd recommend using an exterior flexible grout such as Dunlop 1.5kg Flexible Coloured Grout - White. Once you're done refilling your grout lines, you should seal them to prevent water penetration. This sealer can be used on the older grout, too, if there is no significant cracking.

Here are some helpful guides: How to remove grout, How to grout wall tiles, and How to seal grout.

Mitchell