tiling onto sandstone wall

[yb4xs]

I am in the process of replacing my ensuite bathroon shower unit (doors only). In taking the old doors off 4 tiles have come off the wall, not a major drama as I wanted to re-secure the tiles anyway.

However, when the tiles came off so did the backing plaster(?) behind the tiles, right back to the sandstone wall behind it which is crumbly. I know pretty much nothing about this sort of thing and was looking for some advice on how to deal with this. I was quite happy to give the tiling a go (we've all got to learn somehow!) but I wasn't expecting this to happen too. A section of wall about 20cm x 10cm is now exposed. What needs to go over this before I can put the tiles back up?

Or if you think this is going to be a big job for a professional, how much do you think it's going to cost to get this sort of thing fixed?

Thanks for any help!

 

[lancenotalot]

The backing plaster that you say came off with the tiles sounds like skim coat and the sandstone your refering to is most likely the backing coat/render. What age is the property?
When the backing coat crumbles off can you see brickwork behind?

 

[yb4xs]

Hi thanks for replying.

No can't see any brickwork. On the bits that didn't come away there's the tiling adhesive then it goes onto about a half centimetre of what looked to me to be plaster but maybe not, then behind that is the wall. It's the wall bit that quiet crumbly.

It's a 1900 tenemant building. The ensuite was built as an add-on about 7 years ago, before we owned it.

I've attached a couple of photos so you can see what I mean. View media item 31580 View media item 31581

 

[lancenotalot]

Thats backing coat underneath.If the skim is coming off like that it would normally mean the wall needs stripping back to the brickwork and reboarding.

If you want a temp fix then give it a coat of acrylic primer on the affected areas then try some patching plaster,I wouldn't imagine it would last very long though.

If the plaster is sounding hollow when you tap it and crumbley then its shot and needs replacing.