1st Job: Tiling directly onto wall

[Stefan]

Hi,

Here's a picture of the lovely wall in my en suite, where I'm planning on building a shower:

photo.jpg

The holes are from where I removed a large mirror that used to be mounted on the wall. I'm going to tank and tile the wall, so my options are:

• Fill the holes, remove the remaining glue from the mirror to make a flat surface, and then tank. OR
• Fix on backer boards (Hardi are easiest for me to get) and then tank.

I guess it should only take an hour or so to clean off the glue and fill the holes, so that's my preference. The question is will it then be harder to tile / have problems with strength of wall? If I tank and have a pinhole, would water damage cause this surface to crumble?

What sort of adhesive should I use to fix to this wall (either for backer board or for tanking?)

Many thanks!

Stefan

[Bri]

Just fill the holes and tank the wall doesn't look in bad condition. What tiles are you putting up? The reason I ask as that looks like skimmed boards, so be careful of your weight limits.

[Stewart]

As above.... What tile are you planning on using and what tanking system......

[Stefan]

Thanks. I haven't decided yet on the tiles and tanking. Will likely use a membrane tanking system, and then some rustic-style tiles. Weight was my concern - how would I work out the limit for this wall?

Thanks

Stefan

[Mike]

you could weigh a m2 of tiles and add a few extra kilos for adhesive. the skimmed wall has a recomended maximum weight limit of 20 kg per m2.

[Stefan]

One more point I've discovered today - the walls bow slightly (<10mm), so I'll need to build out slightly with adhesive. So it looks like my options are:

1. Get some light tiles, tank and tile directly onto the wall.
2. If I (well actually the missus), decide to go for heavy tiles, I'll need to do something about the wall. So can I just put on backer boards with screws and adhesive, or do I need to remove the existing plaster first?

Removing the plaster feels like it's going to be messy and difficult, any other options?

Thanks

Stefan

[Bri]

You could over board with backers but you must make sure when you screw them to the wall that you screw into the stud work or if its a dry lined/render and skim wall, srew right through into the brickwork. You'll need some long screws!!!

[widler]

Just fill the holes and tank the wall doesn't look in bad condition. What tiles are you putting up? The reason I ask as that looks like skimmed boards, so be careful of your weight limits.

its roughed on and skimmed bri,either browning or bonding. still got weight issues though,either way

[Stefan]

Okay, so if the weight will be a problem, is removing the plaster the best option? Can it be done easily with an SDS chisel?

Thanks

[aph257]

SDS plus 3" chisel works brill. i did a 4 x 2.5 mtr wall in 20 mins last week. don't forget to wear mask and goggles and seal up door or you'll get dust all over house.

[Stefan]

Progress...got my SDS drill, and started taking off the plaster. It comes off pretty cleanly to the layer below:

photo(1).jpgphoto.jpg

It looks to me like this layer is concrete? There are stones in the wall, and I guess it's harder than the plaster, since the chisel going through the plaster easily but making much less impact on the layer behind.

Presumably the concrete layer is the one I should be fixing the backerboard to, with both adhesive and screws? How clean does it need to be - in some areas the plaster comes off perfectly right back to the concrete, in others there're clumps of plaster left. Should I be meticulous about removing all the plaster?

Thanks

Stefan

[steve187]

the layer behind the plaster could be building blocks either concrete, breeze or Hemelite, concrete are or course concrete, breeze are a black messy substance and hemelite are a pale grey and very light in weight. once you know what they are post again.

[Stefan]

Thanks. The layer is a pale brown, like sand. It's rough, and has lots of stones in it, up to about 1cm in diameter. Doesn't sound like it's breeze block or Hemelite, so I'm guessing concrete. It's a bit hard to tell with all the plaster, but I think they are blocks - there are disconnects where the edges don't quite line up. At some of these there appear to be deeper patches of plaster - could the wall have been built with gaps which were then filled with plaster?

Not sure how much of this is relevant, just posting everything I can see!

Stefan

[easyt]

If it was a soft thermalite block the chisel would go through it like knife through butter. The picture is a bit too close to make out. How old is the property and whereabouts in the country. Is it a normally constructed brick outer skin?

[Stefan]

I'm in Cambridge, the house was built in 2002. The outer walls are brick, if that's what you mean. The wall I'm working on is the one bordering the next house along in the terrace.

The chisel goes through the plaster very easily, but mostly stops at the blocks, so I can push it along and strip out a channel of plaster, without going into the layer below. If I catch an edge of the blocks I can take out small chunks of them, but they're definitely much harder than the plaster.

[Stefan]

Update:

I've stripped back both walls, on one side I've got concrete blocks, which I'm going to apply battens to and then the backerboard, and on the other side, I've got a partition wall, made of some soft grey blocks. That one I'm going to attach the backboard with adhesive and screws.

Thanks for all the advice!