Interior walls rendered in concrete

[Lindyboo]

Have just discovered that all the interior walls in our cottage, apart from a couple of exterior ones which are boarded and insulated, are rendered not in plaster, but concrete, about 1 inch thick.

I’ve assumed this is a bad thing, but am I right?

Thanks

 

[FamilyWiggs]

Are you sure? You mean real concrete - balast and all. Sounds a little odd, and I can't imagine it was easy to do!

This is a bad thing - particualrly if you want to remove it!!!

 

[Lindyboo]

Well, fairly sure, but I confess to some ignorance, so maybe its cement, but I further confess that I don't know what the difference is between the two. The stuff is grey, rock hard - which explains why I've never been able to hang pictures - the nails just bend when I hammer them. The only stuff that I've managed to knock off the wall has been where the damp has got behind onto the brick, but the further from the damp the more solid it gets and eventually can't be worked any more. And the stuff I've managed to remove brings away the surface of the brick and the mortar with it. If I could figure out how to post a pic I'd show you ...

The render is quite tatty, insofar as it's uneven and the previous idiots had papered over it and hoped for the best, so we'll have to do something to get them smooth. There's no way we can get this grey stuff off - a whole house of it and it's as hard as - well, concrete. Sigh.

 

[Flyfisher]

Possibly it is cement mortar rather than concrete as such, which I understand to mean a mixture of sand, aggregate and cement - then standard mx (in my limited experience) being 'C20' meaning aggregate up to 20mm diameter.

Our old larder was also rendered with cement mortar. The 'skirting' was also made of the same stuff, although it couldn't have been original since that part of the house is 18th century.

Is there any actual need to remove it, especially if it would cause significant damage? Do you know where the damp was coming from? Most of ours was the result of failed guttering depositing water on the outside walls - now fixed, hopefully!

As for hanging pictures, you might have to resort to drilling a small hole first and using a rawlplug & screw instead of a nail.

 

[Lindyboo]

Thanks Flyfisher. Perhaps it's cement mortar, which I've not heard of before. I think the render is best left, so I'm pondering ways to create a smoother surface. Options seem to be either plaster over the whole lot - which will mean hiring a plasterer to get a good smooth finish and the budget is now very tight - or dot and dab plasterboard over it. The only place where it absolutely must be removed is from the side of the main chimney breast, an area of about 4 x 7 ft. This has been slapped on very thick with a nauseating attempt at a rustic finish and it interferes with plans to locate a new door frame.

The damp causes have yet to be identified. I suspect in one location (bottom of a door frame) that the dpm is missing from that area, but we expect the builder to be digging up the floor in the next room in a couple of weeks, so he'll be able to tell us. The other main area is in the corner of the chimney breast, where damp - in fact wet - had come through the wallpaper and along the alcove. This clearly had been an earlier problem as the render had been patched with a very sandy mix of sand/cement. Having removed this all is now dry, but the bricks aren't good enough to leave exposed, so it'll have to be covered up with something. It's been suggested to me that the damp here is coming down from the chimney, but we had a new roof a few months ago. Any suggestions welcome.

 

[FamilyWiggs]

Options seem to be either plaster over the whole lot - which will mean hiring a plasterer to get a good smooth finish and the budget is now very tight - or dot and dab plasterboard over it.

I think you might be surprised at how cheap a thin plaster skim is, if you approach your local "cash in hand" Barrat home plasterer doing a bit of "freelancing" in the evening.

Of course you are leaving it to his conscience to declare all taxable income and to reimburse his regular employer for the materials he just "happened to have in the van". :wink:

 

[Lindyboo]

Well, that's a thought. I suppose there might be one or two chaps out there who would consider such a thing ... I must learn to think outside the box.

 

[jocelyn plummer]

Yes, I think that it is a cement mixture. We had it in our Medieval property, covering some wall paintings. I longed to remove it because we had traces of the paintings upstairs, and a couple of other properties in the village did have work done to expose the paintings over the fireplaces.

We were advised that it would be a long and messy job, preferably for the professional .

 

[Flyfisher]

I think you might be surprised at how cheap a thin plaster skim is,

Yes, and even if you cover it all up with plasterboard won't you need to skim that anyway?

 

[Lindyboo]

Been looking into that (a la internet) and many say that the done thing for some years has been to wallpaper straight onto the plasterboard. I recall having done that - in ignorance - about thirty years back. It works surprisingly well as long as the wallpaper lifts off and leaves a lining behind, or you line it first and make sure the board is sealed. I know it's cheating, but desperate times etc ... We've just had the quotes in for the main work here and needed a stiff drink to accompany them, so some economies of cost and time must be made at this stage, or the essential work can't be done.