Leaking shower wall grout joints, best patch material? - Tile Advice

[Mick]

Hi,
I am new to the forum. I am a keen DIYer. I have a problem which I thought would be pretty widespread but I cant find much information on. Could any experienced tilers please help?

I have a 3 sided tiled shower cubicle (porcelain tiles on gypsum plaster on brickwork, a resin shower tray has factory fitted upstands on 3 sides behind the plaster). It's about 20 years old, recently dampness has been showing in the plaster of adjacent rooms, up to about 0.6m metre high. I am sure water has been getting through the grout joints which have fine hairline cracks.

I have taken off the tiles above the shower valve, well above any dampness and I was looking at patching up the plaster walls and tanking the plastered walls with Aquaseal and retiling the lower walls. (The copper valve feed pipes were also embedded in the plaster and I was looking at wrapping these in duct tape and felt prior to filling.)

I am struggling to find the best material to patch the plaster with? I did consider using Tetrion which is a powder filler I had, apparently suitable for inside or outside but their technical dept. said find something else. I know the best base for tiles is sand cement render but I don't know how suitable it would be for a bit of repatching of gypsum plaster? I don't want to hack off the plaster because over 95% of it is in perfect condition.

Can anyone help?

It would be much appreciated, Thanks Mick

 

[Spare Tool]

Prime it then patch with rapidset tile adhesive..

 

[Mick]

Prime it then patch with rapidset tile adhesive..

Thanks would you prime with PVA?

 

[Waluigi]

Get some celafelt around the pipes if there’s room. Duct tape is widely used but it’s not really the right product as it doesn’t allow the pipes to expand properly within the wall

 

[Blunt Tool]

As above acrylic prime then rapid set flexi adhesive

 

[Mick]

Thanks for your replies!