Tiles on plywood in shower area?

[mag]

Hi everyone, I urgently need some advice, I am not a tiler or in a building trade at all, but I am a bit worried re the job that is about to be done in my shower. It's a 100 year old building, the workmen just took the old tiles off in the shower and the wall underneath is completely soaked, some parts (old plaster) are crumbling etc. Last night they brought in two plywood boards, a tub of Unibond super PVA and a tub of Travis Perkins non slip tile adhesive and are hoping to complete the job today.....
I know little about tiling, but when I think of putting plywood on wet walls, PVA on top and tiles stuck on top with an adhesive that is not really designed for very wet / humid areas with poor ventilation I fear I might be redoing the whole thing in the next few months again.
Can anyone advise me on some suitable materials for this job? Thanks a million!

 

[chrisroe]

your fears are correct this is only going to work for a short time

i cant post now as ive got to get the kids to school but im not working today so i should or someone else will fill you in with the correct methods

can you confirm type and size of tile etc
power shower ?
extractor fan
shower over bath or shower cubical

see you later

why not try to delay the work till tommorow as you will have all the info by tonight

this is why the forum is so useful

gtg

 

[mag]

Thanks Chris for prompt response. I am thinking of delaying, not the least because the walls are still very wet.

It's a shower over bath. Not a power shower, but it is quite powerful as the water comes off mains and a combination boiler and this area always has a good water pressure. There is no window - just an extraction fan. The bathroom is small, about 1.5m by 3m. The problem is this is a housing association property, so I cannot hope for anything else but the cheapest materials, including the tiles - simple white, suppose from Travis Perkins again. However, the HA has an obligation to do a decent job and I am not prepared to be taking days off work and no use of bathroom for a family of six again in a couple of months time.

 

[Deleted member 9966]

Hi mag

where abouts are you?

I'd ring the HA now and tell them that the walls are soaking wet and that if the workmen cover it up and tile over it, then they're just storing up problems for later. Any idea why the walls were wet behind the tiles? Had the previous tiles/adhesive/grout failed could you tell?

PVA isn't a material that is used as a primer anymore. Tubbed adhesive + PVA = adhesive taking a long time to cure. And you're correct, plywood in a wet area, particularly if not correctly waterproofed (and I don't mean with PVA) is a repair job waiting to happen.

Get on to the HA and tell them that you're not happy with the materials being used. Are the walls where the plaster has come away brick walls? Are there any internal stud walls that need repairing?

GRR

 

[Matt]

There is no point in tiling over the walls if they are wet. Why are they wet? Has the problem causing that been sorted?

If so, there are a few ways to do it properly. You can use plasterboard if the tiles are just a small cermaic tile (Which I presume they are as you said they are basic white). The area around the shower needs to be tanked if it is to last long term. Especially with a family of 6 as I imagine the shower is used numerous times, daily. You can either use a tanking membrane or a paint on paste.

Once the taking has been applied and is dry, I would recommend a powdered cement based adhesive to apply the tiles.

If they are larger (Heavier) tiles, then a tile backerboard like Aqua Panel or Hardibacker would be needed. It would be better to use a tile backerboard either way, as water wouldn't damage it if it ever did get through (Which if tanked properly it shouldn't)

Hope this is of some help

 

[dock]

Structure behind tiles needs to be dry before they carry on. If this cannot be achieved remove plaster and fix cement based boards to brick.
Given the size of your family to anticipate use of the shower it should be tanked prior to tiling and Mapei Mapegum WPS would do this in conjunction with Mapeband.

Tiles must be fixed in a powder based adhesive to a tsanking system - not ready mixed. Keraflex would do this
As the shower is tanked will not need a water impervious grout so a water resistant one will do and Ultracolor Plus could be used.

Note British Standard recommendations that state that 14 days should be allowed following tiling before using the installation

Chris may well add to this once he's dropped the kids off!!

 

[mag]

Thanks everyone for helpful responses. I asked my Housing Association for this job, because water was coming through to the adjoining bedroom. It seems that the reason for the ingress was poor previous tiling and the water was coming through grout, cracks etc. There are no leaks from the plumbing or the chimney breast plus the wall surface was the wettest on the surface, just under the tiles. That's why I want this to be sorted out once and for all and properly.

One of the walls is the main, brick wall and covered partly with the old plaster (the one that has horse hair in it!) and partially with newer plaster, that is just turning into red sand when you rub it (sorry for my lack of knowledge of proper building terminology!). the other wall was a plasterboard, but it disintegrated when they were taking the tiles off, so it's just a gaping hole with wooden battens to which the other plasterboard (the bedroom's wall) is fixed on the other side. So the hole needs to be closed with something and the other wall needs to be prepared for tiling.

They still haven't arrived, I will be calling my HA now... thanks everyone and if you have any further advice, I would be ever so grateful.

 

[Deleted member 9966]

Mag

Tell them that if they want to avoid having to re-do the bathroom due to water ingressing behind the tiles, then they need to use the correct materials and include some form of tanking material. Tanking can either be a membrane roll or a paste. I have used the Mapei paste myself and it's easy to apply. It's a little bit more expensive than you would hope, but if it saves you having to rip out the bathroom after a couple of years, then an extra £40 ish is worth it.

And rather than using plywood, simple plasterboard (plus tanking) will be more than effective. Do not let them use the PVA anywhere.

Give the HA hell mag :smilewinkgrin:

 

[chrisroe]

Back home now

Bloody hell havnt you lot got work to do
well done everyone i dont think i can add to this so

im off to physio then iceing my ruptured crisiate ligament in my knee

 

[Deleted member 9966]

Back home now

Bloody hell havnt you lot got work to do
well done everyone i dont think i can add to this so

im off to physio then iceing my ruptured crisiate ligament in my knee

this is work :lol:

ok ok, I'm a woman, I can therefore multitask

keep us updated mag... if you get more information from the HA and workmen let us know what they are saying.