Loose plaster and cement behind

[Jack155Q4]

Hi,

On our new house (new to us anyway) we have started stripping back the old wallpaper - it is coming away well but so is some of the plaster and the sand/cement behind.

I am tempted to get a plasterer to fix it up and make it a nice flat paintable surface however money is a little tight with a number of other projects to do.

My main issue is that the layer of sand cement that was applied to the bricks (1930s house) has come away in some areas and on others where it looks fine there is a tapping noise when you knock the wall with your knuckle suggesting it is not properly bonded to the bricks.

I guess ideally you pull down the entire plaster finish and the sand/cement down and go back to brick but I really don't want to go down that route due to the expense at this stage.

The sand/cement certainly won't go anywhere (of course I would never had known if we hadn't started stripping the paper.

Could I get away with a skim and hope the cemented parts do not deteriorate too much after and cause cracking? Are there any particular products to try?

It is on quite a large area (hall way, stairs and landing). For the area where the cement has come away completely I will fill it with some mortar and finish with multi purpose plaster.

Many thanks for any advice.
Jack

Photos (I will get a photo of where it has gone back to brick later today):

 

[joe-90]

Yes you can usually get away with it when the really loose stuff is removed. Your patches will anchor the existing in place.

 

[Jack155Q4]

Hi Joe,
Many thanks.
Could you just give me a quick guide on what to apply to the bricks.

I am thinking of a pva then mortar to bring it up the level of the existing and then finish with a layer or two of multi-purpose.

Jack

 

[NickB_99]

Could you just give me a quick guide on what to apply to the bricks.

I am thinking of a pva then mortar to bring it up the level of the existing and then finish with a layer or two of multi-purpose.

Yes, diluted PVA approx 4 or 5 parts water to 1 of pva.
Paint the day before - especially attention to the edges of the existing.
Then paint with it again just before plastering (when tacky/sticky)

You don't use mortar as such to fill the patches - mortar is usually a term reserved for bricklaying.
If your house has a cavity wall, then probably be easiest to fill the patches with Bonding or Hardwall.
Render is the cement/sand mix that I think you mean. That is usually a bit more work than gypsum undercoat plasters (mix ratios, additives etc and takes longer to set), but would work fine also.

And your finish plaster is Multi-finish (not multi-purpose)

 

[Jack155Q4]

Many thanks. I will be doing this with help from my Dad who has plastered a fair few times over the years so hope now to make too much of a mess.

Regards,
Jack

 

[iturner15]

I just had the same problem. I used thistle undercoat plaster then skimmed over the whole room (only because I wanted to do the whole room mind) I'm sure you could fill the gaps flush with plaster

But, since, been advised to use hardwall or bonding (as above) then multi finish. Check out my threads I've started

 

[Jack155Q4]

Looking forward to getting stuck in to this.

A photo of the exposed brickwork and previous repair job that was hidden by wallpaper: