Behind the plaster coat it's like very crumbly sand

[Iainw123]

In my conservatory I have had an issue with penetrating damp.
We have found the issue and corrected it ( hopefully)
Now I need to get the walls decorated again.

I noticed a few hollow sounding bits of plaster so took them off and beneath it was what appeared to be solid plaster. Although some bits have black marks ( which I think may be some kind of mound)

I found one really damaged bit and pulled it off and what can only be described as a waterfall of sand poured out. As I pulled out more and more plaster it revealed that pretty much all the wall behind the "good" plaster is like flaky, crumby sand.

I thought before I pull it all off I should consult the experts.
Do I need to pull it all off and go right back to the brick and get someone to re-do the whole wall or it it much easier than that and there is some way of rescuing it?

i will try to put up a photo in a second post

 

[Iainw123]

I think I have uploaded a picture below. You can see the crumby sand like stuff in the top part and the plaster that on the surface looks ok but I think is crumby behind it.
Maybe I should point out that none of the pink plaster sounds hollow when I tap it

 

[roughcaster]

If it's as bad looking as you say, i'd remove the whole lot back to brick. Once you start messing about with that old sandy basecoat, you can sometimes open a can of worms. You said you had a penetrating damp problem that "hopefully" has been sorted. By removing all the old stuff, it gives you a chance to look at the old brickwork, and think about whether to re-plaster onto it again, or do what a lot of people do now with old problem walls, and that is to remove all the old plaster, check over the joints in the old stone/brickwork, re-point if neccesary, (some even cover the wall with a membrane) then strap the wall with treated timber, insulate between it, and then plasterboard it with 12.5mm thick, foil backed p/b. Once the wall has been boarded, it would then be taped, and you're then ready for decoration. Whatever you do, I certainly wouldn't plaster onto that old brickwork with Gypsum plaster, (lime plaster maybe), especially knowing you've had an issue with penetrating damp. I'd go for the insulation/plasterboard option, but this is just my opinion, others will have theirs.

 

[vinn]

What was the original issue?
Is this wall the rear wall of the house?
Is the opening in the wall a doorway?
The elec cable protection seems to be very close to the surface


The sandy base coat is an improper render mix - typically you will have to hack all off back to bare brick, & start plastering or rendering again. Be cautious hacking off around the "mound" & the cable.
Is the house/rear elevation rendered?

The ceiling seems to be badly boarded - is this a DIY job?

 

[Iainw123]

Thanks guys
It's looks like I have to take it all the way back then.
What a pain... But I'd rather do it properly.
The ceiling is currently being replaced.
It was a conservatory with a plastic see through ceiling but now I have someone replacing it with a timber roof and they have insulated it and boarded it. It just hasn't been plastered yet that's all.
The builder is away this weekend so I wasn't able to ask him about the wall.
I guess I will need to pay him to re-do that wall now

Thanks a lot guys for your replies

 

[Iainw123]

Forgot to say what the original issue was
It was old guttering that was blocked ( all replaced now)
And not enough flashing ( whatever that is!)