Should I plaster concrete walls and ceiling?

[SpicyTomatos]

Walls are currently covered in wallpaper (which is falling off) and painted, and the ceiling was previously covered in Artex, but is now bare. All the concrete surfaces seem quite smooth.

So should I get it plastered?

If I don't, it will clearly save money, but I was wondering whether there are some disadvantages of this e.g. noise travelling more easily, looking terrible etc.

Any help would be much appreciated.

Hi.

By concrete walls, do you mean you have scraped off the wallpaper and Artex and there is grey cement rendering where you would expect plaster ? I am not being deliberately pedantic, concrete is something altogether different and is likely to throw everyone of the scent.

If it is cement render then the only advantages of plastering it are firstly, obviously a smooth finish and secondly you mention wallpaper which will not stick well to untreated render. If you are papering over it and the render is in good condition, then you will need to prime the surface first to enable the paper to adhere properly to the walls . Traditionally this was done with diluted PVA adhesive, you may need two coats. If you are painting it then to stop it flaking, just dilute the first coat of paint approx 3 or 4 water to 1 paint depending on the paint. Don't worry if it seems really thin, that's the point, so it soaks in well. You should really do this with fresh plaster in any case. It's unlikely to look as smooth as a fresh plaster finish but that may suit the look your after and will certainly cost less.

Hope that helps.

Many thanks for your reply. It is very useful.

I'm not sure I can answer your question which shows my ignorance! The building is made out of concrete, the artex has been scraped away and wall paper will need to be in due course. It is possible that the exposed part is not the concrete core, but everything I have heard from the workmen suggests that the exposured ceiling is concrete.

I would like to paint it rather than wallpaper it, and I think you have answered that question - the main downside is a slightly rougher finish. I was also a bit worried about sound travelling more easily along the wall and therefore annoying the neighbours.

It would be a lot of plastering though, so the saving would be nice.

I'd actually quite like to polish it, but I'm not that brave.

It may very well be concrete then. It's unusual I think, as in all the concrete houses I have seen, the exposed surface is rough to say the least. As regards to sound transmission. Not to bore you too much but sound absorption is measured in Sabin's and I have just checked a chart and it's exactly the same for a painted plaster and masonry wall as it is for a painted concrete wall so no worries there. The link to it is here in case you need to show it to someone. www.acoustic.ua/st/web_absorption_data_eng.pdf

Good luck.
PS polishing concrete is expensive and messy as you no doubt aware, also for best results, the blend of the concrete mix is usually chosen beforehand with polishing in mind. Looks good though.

post plenty photos please

We plastered ceilings and used lining paper over concrete walls, then painted that and it looks fine.

Couldn't leave them exposed as they were covered in bloody lead paint

Goldmonday - Thanks that's interesting. I'm wondering if that is what is covering the walls at the moment. It doesn't look like wall paper - everyone assumed it was simply painted until the artex removal from the ceiling ripped some of the paper off the walls and it became visible. How much did it cost in comparison to plastering?

PigletJohn - I will try to post photos on the weekend (I don't have any)

KitchenGuy - Thanks for the acoustic ratings. That is very useful and reassuring.

Please see attached photo.

Having looked at it again, the exposed wall is clearly not concrete. Not sure what it is.

The ceiling looks like concrete to me though.

is it blocks?

Can you scratch it with a teaspoon? What colour is the dust? Is it gritty? Can you press a drawing-pin into it?

It might just be a grey plaster.

When you rub your hand over it, does it feel smooth and flat?

In some districts, a sand and cement render is applied to the internal walls in place of backing coat of plaster, then a thin skim of fine plaster over the top. But it feels quite coarse and gritty, due to the sand.

having enlarged your photo, I gather that the lower part is wall and the upper part is ceiling. The wall looks like plaster where you have peeled back the paper, and the ceiling does look like concrete. If you stand back and take a wider shot we might be able to see shuttering marks (probably in 8ftx4ft sheets, but might be "planks")

I think I can see air-holes in the concrete, which surprised me as they are usually on the upper surface.

Are you in a house, or a block of flats? How old? I find it strange to see bare concrete in a domestic home, unless it was intended to have a suspended ceiling (especially in a bathroom where here might be plumbing and ventilation ducts) or a storeroom or garage.

Looking on the bright side, a plasterer would usually charge "a few hundred pounds" to do a ceiling. Better value when you have several rooms done at once so you can have a solid day or two's work done. It might need PVA on day one, and plaster on day two.

Don't put PVA on a surface you hope one day to paint.

Thanks for your help.

It is a block of flats. Built around 1970.

The sand and cement render might explain the wall coverings. It is a little coarse and gritty. The ceiling is much smoother.

I was quoted £650 to plaster the ceiling which is ok (there are a lot of ceilings). I only really started to think about it when I realised I had to do something to the walls as well. I began wondering whether I really needed the plaster at all.

So, what do you recommend for the walls? Remove all the paper, plaster and paint? Or is it best to go with the liner and then paint as someone mentioned above?

if you have confidence in your plasterer, grt them to look at the walls and make a recommendation. It will (should) work out better value to have the whole lot done in one go. If the walls have been rendered they may only need a finish skim.

Before plastering, consider if you need any electrical (or plumbing) work done, such as wall sockets, switches, TV cables, speaker wires, LAN cabling, phones, or ceiling lamps, There might be conduit cast into the concrete ceiling, but it is very difficult to make neat alterations or additions. If they are going to be plastered over, it will be neater and easier, and you will get a better finish. If you have a concrete floor, you won't be able to put cables or pipes under it. Kitchens in particular need a lot of outlets.

If it was me I would also strip off the old skirting and architrave, otherwise the plasterer will try to meet them, but it will not be perfect. They are both relatively cheap to buy, and easy for a chippy to cut to neat corners and fix to the walls on top of the new plaster.

Thanks for the reply and the information.

I struggle to be that confident in any of the contractors as I am way out of my depth, and they all seem to contradict each other! But I am having quite a bit of work done, so I can at least ask two different parties for their opinion. Plus they have all been reasonably well recommended.

Yes, there is a concrete floor, and the plan is to remove and replace the skirting.

There are no conduits for the wiring (to the surprise of the electrician), they are all set in concrete which isn't ideal. The plastering / painting will be the last thing done. Most of my neighbours have fitted false ceilings and solved the problem that way, but that going to be too expensive.

I should really give some thought to TV and LAN cabling.

Thanks again.

ask your sparky if he agrees with my suggestion, which is to run oval conduit all round the room, about 450mm above floor, for the socket circuits, with another one for phone and LAN, and another one for TV.

It is then very easy to cut into it at any point to add a new outlet, and this is quite an economical method in labour and materials (no up-and-down legs).

Of these, the sockets are the most important that you can't live without.

Phone, alarm, LAN, aerial and speaker cables can be run behind skirting if necessary (space them off the wall on 18mm battens) but anything carrying mains electricity must not be. If you run the battens before the plastering, fit the upper one to coincide with the top of the skirting, and let the plasterer work down to it. This will prevent the skirting sticking out too much.

If the skirtings are fixed to the battens using screws (not nails or glue) then they can be removed and refitted if necessary with minimal damage apart from a spot of paint. I might have some photos somewhere.

That photo looks exactly like wet pour concrete to me. Right down to the discolouring and lines from to the shuttering to the pin holes from trapped air. The irony is that a lot of interior designers are leaving exposed concrete just like that as a trendy finish. If your on a strict budget just seal it, line it and paint it and it will look fine. If you can stretch to the cost of plastering that's always the best option and you can hide any new wiring in safe zones under the plaster. Your electrician will know where they are. Good luck.

Like PigletJohn above, just enlarged the photo and can see it is wall an also a ceiling. Looks like concrete ceiling and plaster walls to me too.

You could batten the ceiling out and plasterboard ( or the walls ) and run any cables on the surface of the concrete?

Zombie thread.

oh yeah , didn’t look at the date 🙂