shower leaking behind wall

[dan_the_plumber]

Hello all.

I have a problem with a shower.

The tiles behind the shower all blew

Customer had them taken off and retiled.

Then they blew again and there was a discolouration of the ceiling in the kitchen below

Customer had tiles replaced a second time.

Then I was called in, I ran shower with cover off and found samll leak inside the shower which i PTFE taped which fixed the problem in the shower.

The wall was then retiled by the tiler.

I then camed back fully sealed where the electrical cable come through the wall with silicon.

I also covered the back of the shower unit in silicon and screwed back to the wall

All the tiles have now blown again!!!

I'm at a loss......Anyone suggest what the problem might be please?

Dan 🙂

 

[spanner]

Prior to the wall being a solid or stud wall, its important to seal pipe, would be good to let us all know if its a solid or stud wall though budd..!!

 

[spanner]

So solid walls then!!!.. The problem sounds like a pin hole. If the feed pipe to the shower is "mains fed" , which they normally are, and the pipe is "copper" consealed in a solid wall without the "LAG" i.e denso tape or plastic protective sleeving, would look like you'll have to disconnect it from point of where FEED enters the solid wall to shower unit, cap it, and start another entry to the instantaneous unit.. Concrete ,sharp sand, ballast, cement, they cause copper to ROT... Well Dan it sounds like it to me if the the unit IS mains FED! Good Luck and hope its sorted soooon. What is the unit. 8.5 9.5 10.5Kw???

 

[Whn1]

The only real way to solve a problem like this is open up a good size of the wall and thoroughly look for the problem.

Be careful with silicon as some kinds of tanking like Tile Safe react with it.

I'd agree with this, the tiles are screwed anyways, expose everything you can. And then work from there.

 

[dan_the_plumber]

Hello again.
I went to tiling merchants and found that a tanking kit was about £75 quid!

Now for a shower room I would definatley by a kit and do it right.

But for this job it's just a wall inside shower cubical.

I know you can use just ordinary PVA the seal before tiling.

I just wondered if anyone knows if this is a good idea or not?

It's certainly a lot cheeper!!!

Cheers...Dan

 

[MattWeth]

Screw fix do the mapei tanking kit for about £35

 

[scottyblen]

does concrete, brick work and screed corrode copper due to electrolysis? copper is not ferrous metal is it?

sorry for the dumb questions i am soon to be doing a course in plumbing. lol

 

[Simon F]

does concrete, brick work and screed corrode copper due to electrolysis? copper is not ferrous metal is it?
sorry for the dumb questions i am soon to be doing a course in plumbing. lol

hello again scotty, copper does corrode in contact with masonry.
it is not ferrous so it does not "rust" but it still corrodes or oxidises

 

[MattWeth]

does concrete, brick work and screed corrode copper due to electrolysis? copper is not ferrous metal is it?

sorry for the dumb questions i am soon to be doing a course in plumbing. lol

No copper isn't ferrous (ferrous means contains iron)

Concrete etc does corrode copper but not via electrolysis - it's a chemical reaction.

Edit: beaten by Simon 🙂

 

[scottyblen]

No copper isn't ferrous (ferrous means contains iron)

Concrete etc does corrode copper but not via electrolysis - it's a chemical reaction.

thanks matey. i was wondering via which way/how it corrodes.

 

[PlumbBobBob]

I know you can use just ordinary PVA the seal before tiling.

I just wondered if anyone knows if this is a good idea or not?

It's certainly a lot cheeper!!!

Cheers...Dan

never ever under any circumstances use pva to seal walls for tiling onto. the tile adhesive will react with the pva preventing the tiles from staying on the walls. read this from the tiling forums.

[DLMURL="http://www.tilersforums.co.uk/tile-adhesive-grout-substrate-preparation/2511-p-v-versus-primers.html"]P.V.A. Versus Primers[/DLMURL]

 

[AWheating]

as steve has said do not use pva to seal a wall for tiles you need to use suitable designed chemicals. Most professional tilers would have tanked the walls prior to tiling, question the tiler why it has not been tanked??

also ready mix adhesives are not suitable for shower areas, it needs to be a cement based waterproof adhesive (powder) if i remember correctly.

 

[dan_the_plumber]

Thanks a lot...Yeah unit is 9.5KW

 

[dan_the_plumber]

Sound advice.....I thought proper tanking and powder adhesive for the best but not sure why

Now I know...Thanks a lot!!!!

 

[gravytrain]

ready mix adhesives are not suitable for shower areas

there are some ready mix suitable for showers. BAL white star or grip, also the equivalent from Mapei

 

[dan_the_plumber]

sorry is that ready mix adhesive and grout or do you mean tanking?

As well as trying to deside on best adhesive and grouts to use

I'm also trying to find a product to water seal the walls without it costing £55 for a tanking kit

Cheers....Dan 🙂

 

[MattWeth]

Gravytrain is referring to adhesive.

There's no real way round the cost of tanking products but I wouldn't do a shower without tanking - for my peace of mind if nothing else.

As I said earlier screw fix do the Mapei tanking kit for £40 if you've got a plumbfix account (item: 78484)

I'd also always use cementitious powdered adhesives and grouts rather than tubbed stuff (even if they are supposed to be suitable for showers).

 

[dan_the_plumber]

Thanks Matt...Nice one 🙂

 

[PlumbBobBob]

i agree with matt. tubbed adhesive is only good for the tubs it comes in really. i only use powdered.

 

[MattWeth]

i agree with matt. tubbed adhesive is only good for the tubs it comes in really. i only use powdered.

And the tanking kits come in the same tubs (and you don't have to clean them out 😀 )

 

[AWheating]

i was always told that ready mix adhesive requires air to set(which is why it stays usable in the tub), so it can take alot of time for it to set fully and its not very water proof because of its make up. Powder on the other hand is normally cement based which dry via a chemical reaction so will set even in damp conditions without air supply.

so i would always go with powder,s with or without admixtures.

plus powder is normally alot cheaper.