shower grout failure ?

[John.Stitch]

A shower in the bathroom 6' square with no window but has a fan. Conversion in 2004.
The shower is in one corner the base has a lip all the way round.

Plywood on top of 3x2 studding was used as the backing for the shower walls which were then tiled.

I noticed fungi growing at one corner of the shower with the wall, when it grew again I took off the pipes covering to have a closer look.

After a shower water can be seen slowly dripping from the underside of the tray, then it goes down the plasterboard wall and to the floor.

Trying to diagnose the fault.
In the shower the grout tends to go grey then black

I have regrouted it once, I also tried silicon which did not last.

The grout I used was Microban for showers.

It could possibly be the water getting over the lip on the tray but the water dripping takes 2-3 minutes to establish after the shower starts.

My diagnosis is to replace the grout unless anyone has other ideas.

There are three pics here;
http://yfrog.com/bfp1000284njx

 

[jctilingservices]

A shower in the bathroom 6' square with no window but has a fan. Conversion in 2004.
The shower is in one corner the base has a lip all the way round.

Plywood on top of 3x2 studding was used as the backing for the shower walls which were then tiled.

I noticed fungi growing at one corner of the shower with the wall, when it grew again I took off the pipes covering to have a closer look.

After a shower water can be seen slowly dripping from the underside of the tray, then it goes down the plasterboard wall and to the floor.

Trying to diagnose the fault.
In the shower the grout tends to go grey then black

I have regrouted it once, I also tried silicon which did not last.

The grout I used was Microban for showers.

It could possibly be the water getting over the lip on the tray but the water dripping takes 2-3 minutes to establish after the shower starts.

My diagnosis is to replace the grout unless anyone has other ideas.

There are three pics here;
http://yfrog.com/bfp1000284njx[/QUOTE]


Did you use a tanking system on top of the ply ?

what type of adhesive did you use?

whats the grout line width?

Is there a good seal between shower tray and first row of tiles?

How long are yous in the shower for

There is DEFINATELY NOT a leak in the pipework of the shower ?

When you say " 1 corner" do you mean where 2 walls meet, or do you mean at the corner just above the tray?

If you mean the internal corner where 2 walls meet, did you grout or silicone the joint.

Did you use a cheap silicone around the tray or a good anti fungal/mildew silicon??

 

[John.Stitch]

Did you use a tanking system on top of the ply ?
From memory no I did not. The wall under it was tanked to three feet up from the floor then the ply screwed on the wall I think. The wall is an external one at ground level but it is very well built even though it is below ground level on the outside by 2-3 feet. I only notice the water after a shower and not on the wall.
--------------------------------------------
what type of adhesive did you use?
I don't have the bag, I bought it the same time as the tiles and grout from a large tiling place in Bristol --Tileflair so should be ok?
------------------------------------------------------------------------------
whats the grout line width?
I used 1.5mm plastic pegs so 2 mm max
--------------------------------------------------------------
Is there a good seal between shower tray and first row of tiles?
Yes, the tray was set in place first then the tiling was done after bringing the tiles down well over the lip on the edge of the tray. The tiles overlap the lip for the full length of the lip which is 1/2"
------------------------------------------------------------------
How long are you in the shower for
5-10 minutes nearer 5 than 10
--------------------------------------------
There is DEFINITELY NOT a leak in the pipework of the shower ?
No there is not for the drain pipework.
I cannot access the shower feed pipes but they are on the other wall from the leak.. But the water only occurs when the shower is on.
It is a Limestone area so scale is an issue in the kettle.
--------------------------------------------------------------------------------
When you say " 1 corner" do you mean where 2 walls meet, or do you mean at the corner just above the tray?
I felt the water on the underside of the tray where it abuts the wall on the LHS of the tray by the loo, not in the corner, but I cannot feel the underside of the tray in the corner.
-------------------------------------------------
If you mean the internal corner where 2 walls meet, did you grout or silicone the joint.
Not that corner but...
Initially I grouted after tiling then regrouted the joint with the tray as some grout had eroded away then I applied silicon and then when that came away by water erosion and then I regrouted again.
------------------------------------------------------------------------
Did you use a cheap silicone around the tray or a good anti fungal/mildew silicon??[/quote]
It was good quality, but it got washed away by the water after a while

The grout was Bal Microflex

Tests carried out:
1.I ran the shower with the head down the waste.
No leak.
2. Ran the shower for 5 mins against the RH wall tiles.
No leak
3. Ran the shower against the LH wall tiles at the second level of tiles.
Water came down the edge of the end of the plasterboard and onto the DPC as per the original problem.

So re-grouting would seem to be the solution.
What is the best way to remove old grout and any tips on brand of grout to use as well please.

 

[jctilingservices]

unless you have a fein multi master or the equivalent with a narrow blade you will struggle to get ALL the old grout out, you could try a narrow bladed grout rake, or possibly a dremmel.

It doesnt matter which grout you use, it will NOT be totally waterproof, unless it is EPOXY GROUT

 

[John.Stitch]

Thank you for your advice and your time to read and comment.

 

[tictic]

you can pick up a dremmel and 1.5mm bits for about 30/40 pounds.
and when it comes to grouting if using bal grout(dependnt on which one) you can a bal GTI to the grout.

 

[jctilingservices]

you can ADD bal GTI to the grout.

Ha ha ha, just thought i would help you out Davie mate

 

[tictic]

you can ADD bal GTI to the grout.

Ha ha ha, just thought i would help you out Davie mate

time for me to get a new phone and pc mate.... honestly it aint me its the pc....
alright anyway jimmy,how is the fishing going..

 

[jctilingservices]

alright anyway jimmy,how is the fishing going..

to be honest Davie mate the fishing is gonna have to go on the back burner for quite a while, fully booked from now until 28th nov, and inbetween those dates i only have 1 day off , plenty other provisional bookings too.

Hows things your end, especially that holiday you gotta pay for

 

[tictic]

pretty much the same here jimmy work wise.

as for the holiday,she is waiting for her pal and kids to get back to her with a date...then i will just work away and come back to a nice quiet house.... ..sounds to good to be true....

 

[jctilingservices]

pretty much the same here jimmy work wise.

as for the holiday,she is waiting for her pal and kids to get back to her with a date...then i will just work away and come back to a nice quiet house.... ..sounds to good to be true....

if i was italian mate i would say it sounds " belissimo "

 

[John.Stitch]

I used a grout rake to remove the grout from 7 tiles on the bottom inside the shower and one on the next row above.

The plywood underneath the bottom row was damp and not too bad on the row above.

The ply in one corner had warped so it came into the shower by a good 1/2", I'll screw it back into place.

Got two pics I'll post when the camera battery is recharged.

I have to let the ply dry out but I'm not sure how long this will take.

Do I apply anything to the ply I have exposed, such as tanking gunge and do I apply any sealer to the bottom of the ply where it meets the tray?

Some of the grout is stained light brown which appears to be the water bringing the wood colour out into the grout.

I am considering renting a Fein Multi tool to remove the grout the tool costs £15 per day to hire and the bit cost £40 to buy (but can be had on the bay for £30) not seen a dremel to look at, there are copies sold in Lidl or Aldi and toolstation.

 

[Richard C]

Using ply as a tile base is a really poor choice & it must always be tanked in a wet area. Apart from expensive epoxy products, even the best waterproof adhesive & grout is only waterproof in the sense it will not turn to mush when wet, they still absorb water; waterproof tile backer boards are what you need in a wet area.

What’s happened in your case is that moisture has got behind the tiles, the plywood has expanded & warped which in turn pops the grout, more water gets in & before too long the whole lot starts to go mouldy under there, smell & then it falls apart. The ply should also have been WBP; if it’s standard ply board water will dissolve the glue the plies will de-laminate & it will fail. If the ply is now wet & has warped, to be brutally honest with you, it’s shot & whatever repair you attempt now is only going to be temporary. IMO your shower tile job is doomed to failure & it won’t be too long before you have to rip it all out & start again. Rather than hiring/buying expensive kit to remove the existing grout & re-grout, you would do better to put the cash towards ripping it all out & starting again but this time using the correct materials.

 

[John.Stitch]

The ply was WBP but from what you say I'll rip it out and start again.

Presumably if the backer board is waterproof I can use standard grout?

The shower is in a corner of the bathroom
One wall is an external wall and tanked blockwork and the other is studding.
So how is the board fixed to the wall and the studding and still being waterproof if you put screws through it?

This is one type of backer board form a shop near to me;
http://www.tileflair.co.uk/category-is-tile-backer-board/

 

[Richard C]

The ply was WBP but from what you say I'll rip it out and start again.

Now the ply appears to be shot, repair will only be temporary & is just throwing good money after bad IMO so probably the best option for the longer term & you'll have a nice new shower enclosure

Presumably if the backer board is waterproof I can use standard grout?

You still need to use a flexible waterproof adhesive & grout of the correct type for your tiles; quality trade products only, not cheapo DIY crap.

The shower is in a corner of the bathroom
One wall is an external wall and tanked blockwork and the other is studding.
So how is the board fixed to the wall and the studding and still being waterproof if you put screws through it?

On timber stud just screw into the stud timber. On brick/block walls, some board use proprietary fixing methods but on others you can use the same method as the Marmox U tube clip; but some manufacturers won’t recommend it!
http://www.pureadhesion.co.uk/marmox-1250x600x10mm-insulated-tile-backer-boards.html

The small penetration of the screw through the backer board is insignificant; Seal & reinforce tape all board joints prior to tiling.

This is one type of backer board form a shop near to me;
http://www.tileflair.co.uk/category-is-tile-backer-board/

Marmox is an excellent product but there are others that are less expensive.