Replastering 1930's Wall - Brick & Cinder Block ?

[Spinny]

Need to get the staircase wall replastered in our 1930's semi. The hollow old plaster came off the brick wall all too easily, but then discovered the second storey is not brick but something else - cinder block or something ? Although some patches are hollow behind the plaster when tapping it, in general it is very difficult to remove because the 'cinder block' and the grey first coat/undercoat of plaster seem to be so well bonded you cannot tell where one stops and the other starts - there is no clear cleave point and you can only chisel where you think the join should be. It is going to be difficult to strip this off but a plasterer said if it doesn't come off and bricks are wet plastered then the lot is skimmed it will crack at the junction line.?

 

What needs to be done to make this ready for replastering ? Am I really going to have to spend hours with a hand chisel trying to get the grey plaster pff the grey cinder block even though there is no real junction between the two ?

[Sparrowhawk]

My 1920s house is cinder block from brick foundations with a brick stringer(?) at the 1st floor joists. It looks like your first floor could be cinderblock but hard to make out from the photos as not enough is visible. It's horrible stuff to work with.

 

Can the plasterer not bed in a wide scrim at the junction to stop it from cracking?

[twice round the block]

Before you go any further. I'd get a plasterer in for some advice and a price, as you maybe removing too much old plaster.

[Spinny]

I have had 2 plasterers in and they said different things.

 

One said take all the plaster off the top of the wall, the pink skim coat and the old undercoat.

The other said he could wet plaster the lower part and then skim the lot.

 

There must be a million houses built like this across the land - has anyone had this issue and how did they resolve it ?

[Mr Punter]

Leave the stuff that is well bonded.  The skim will be able to bridge the 2 substrates.