Shower leaking - regrout?

[Crosby99]

Noticed this leak after someone had a shower in the rarely used guest bathroom. This picture is from the entrance hall, below the guest shower room.

Similar thing happened a few years ago when we had house renovated, and the builder then put some more grout on the shower floor which seemed to do the trick.

I believe the grout has failed again (or was never designed to be watertight) and there is no tanking.
I ran water directly down the plug hole using the shower hose and there was no further evidence of the leaking. Thus the determination of the grout being the culprit.

Question for the PH hive mind is what's the best way to sort this?

Is it the remove the 'old' grout and then use an epoxy grout? Or is there an easier quicker way?

This shower room is used very infrequently, so the solution needs to have longevity, but will not necessarily be hammered by use...

Edited by Crosby99 on Saturday 2nd November 14:07

Edited by Crosby99 on Saturday 2nd November 14:08

Edited by Crosby99 on Saturday 2nd November 14:11

[Crosby99]

Some pictures of existing grout

Edited by Crosby99 on Saturday 2nd November 14:13

[Belle427]

I would guess the floor is moving too much hence the cracking, is it upstairs on a wooden floor?

[Little Lofty]

The tanking has failed as has the grout, for an infrequently used shower its pretty poor. You could re-grout, but it will never be 100% without ripping it out and starting again. My friend has just had the same problem, multiple attempted fixes and then enough water to bring down his kitchen ceiling, he has just had it redone from scratch, this time with a large tray rather than tiles.

[GasEngineer]

Tiles.

[Crosby99]

They are wood effect porcelain tiles.

If I take the short-term/cheaper option of a re-grout as opposed to ripping it all out, what's the best way to remove all that grout?
A grout rake or a multitool?

If it's a multitool (I can borrow a friends cordless Makita), any blade recommendations?

[Stevemr]

I don’t know if this is the correct solution, but I think I would take out the existing grout, then redo it with a brown silicone sealant.
I suspect there will be a bit of movement with the floor and silicone being flexible may allow for that.

[colin79666]

What is under the tiles? Grout isn’t 100% waterproof.

[8-P]

Stevemr said:

I don’t know if this is the correct solution, but I think I would take out the existing grout, then redo it with a brown silicone sealant.
I suspect there will be a bit of movement with the floor and silicone being flexible may allow for that.

You could try this I guess, if the shower isn’t used that much it might be ok. I’d be tempted to dribble some Captain Tolleys into all the gaps first. Let it find the gaps/ leaks

https://www.force4.co.uk/item/CAPT-Tolley/Captain-...

Ultimately as others have said this would be patch up and not a final solution.

[Vanden Saab]

Rip it out and do it properly. The only reason you lose grout like that is movement in the tiles and/or floor beneath. Nothing else you do will fix it.

[Indecision]

colin79666 said:

What is under the tiles? Grout isn’t 100% waterproof.

Very much this - if the shower hasn’t been tanked it’s always going to be problematic. I’d strongly advise removing, tanking and refitting.

[Little Lofty]

Crosby99 said:

They are wood effect porcelain tiles.

If I take the short-term/cheaper option of a re-grout as opposed to ripping it all out, what's the best way to remove all that grout?
A grout rake or a multitool?

If it's a multitool (I can borrow a friends cordless Makita), any blade recommendations?

If you use a multi tool there is a high chance you will go through any tanking that has survived, it could make things worse. As mentioned, for the grout to fail like that on a lightly used shower something is seriously wrong with the subfloor, plus once the tanking is compromised you are wasting your time on anything thats not a full rip out.