How to fix grout hairline cracks?

[Joshuam08]

Hi Bunnings community, I noticed some hairline cracks (and one small hole) in some of the grout lines in our shower base. The grout is only about 2 years old. I was wondering if these cracks mean the grout needs to be redone or can this be normal? It does appear to be happening on the narrower bits of grout so I assume it’s weaker.

 

 

  

If not normal, does it need to be completely removed and done again or is there a way to get more life out of it without redoing it all? Wasn’t sure where to ask so thought the experts here would know!

[JacobZ]

Hi @Joshuam08,

Hairline cracks in grout are pretty common, and they don't necessarily indicate a larger issue requiring a lot of action. They are likely due to the slight expansion and contraction of the materials.

Having a look at the cracks in your specific grout, unfortunately, they are not wide or deep enough that you could simply add some more grout, so I would suggest using a Grout Saw to scrape out the grout around the hairline cracks and holes, then replace them with some Dunlop Ready-To-Go Coloured Grout in the closest colour to your grout.

You can use a QEP 4 x 9" Economy Grout Float to press the grout into the lines, ensuring there is enough grout to fill the grooves and that it is pressed into the gap to ensure it makes good contact with the surfaces on all sides.

Once the grout is in place, clean up with a wet sponge, then allow the grout to dry.

Once dry, you might also like to use a sealer such as this Dunlop Grout Sealer, which will make the grout repel water and stay cleaner for longer.

Let me know what you think and if you have further questions, please don't hesitate to ask.

Jacob

[Joshuam08]

Hi all,

a follow up to this old post. Looking at finally trying to fix it up, but also noticed today my tile waste insert isn’t actually fixed in place anymore and can be moved in and out. I assume this is due to the grout cracking almost completely around one side of it. What’s the best way to fix this back into place? Clean the old grout around the edges, apply some new grout on the edge of the tiles and push it back into place?

 

[MitchellMc]

Hi @Joshuam08,

The proper fix would be to remove all the cracked grout surrounding the waste cover frame, then secure the frame back in place with a few dabs of wet-area silicone. Once that’s cured, re-grout around the frame so it’s locked back in properly.

If the insert is still fairly stable and you just want to stop it from moving, you can take the quicker route: clean out any loose grout, put a few small dabs of wet-area silicone underneath the frame, press it back into position, let the silicone set, and then fill any hairline cracks around the edge with a bit of fresh grout.

The full grout removal and re-grouting method will give you the longest-lasting result, but the silicone-and-touch-up option works fine if it’s otherwise solid. 

Please let me know if you have any questions.

Mitchell

[Joshuam08]

Hi Mitchell,

Late update. We decided to get someone in to regrout the shower with epoxy grout. They also fixed the drain cover back down. However, unlike in the earlier photos where you could see the what I assume was the screed and 4 blobs of glue to hold it down, they have glued 360 degrees around the drain cover which will definitely hold it in place, but I'm just wondering if the glue is usually porous and will still allow water that ends up under the tiles to escape along the waterproofing membrane to the drain? Or will this prevent that action and I need to get them back to remove it so there is gaps for water?

Thanks!

[JacobZ]

Hi @Joshuam08,

It really depends on the type of adhesive they've used. 

To me, it looks like a tile adhesive, probably cement-based, which is water-resistant, but not fully waterproof, so it should allow trapped moisture to seep through.

If you weren't aware of what they used, it might be worth giving them a call and asking what adhesive they used, as this would be the deciding factor.

Let me know what you think.

Jacob

[Joshuam08]

Hi Jacob, based on the info provided I think it is tile adhesive and probably cement based as well. I did ask as they left if moisture could still escape and they said yes, but wanted to confirm as when googling if moisture could pass through tile adhesive, the answers were mixed (primarily saying water resistant and should be able to pass but some results were saying no). Sounds like we should be okay then!