Crumbling Cinderblock?

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fadeout32

New Member
Hi All, I'm wondering what the best course of action is here. I've pulled the skirting boards off the walls to start a redecoration of a room, but now have a crumbling area as shown here:

IMG_20200731_182948.jpg


And in a wider view:

IMG_20200731_182938.jpg


We think that's cinder block as its a 1930s house. The previous owners had the room replastered and I think they just patched this section after stuffing it with newspaper. The section cracked and bulged into the room after removing the skirting board with a pry tool.

I'm not sure what the best course of action is, at the moment, we're thinking to use two coats of PVA and then mortar to fill the hole before plastering. Any advice or guidance you could offer would be appreciated especially if there is something we absolutely should avoid or something to bear in mind about cinderblock (if that is what this is).

Cheers.
 

Cockney1

Well-Known Member
Hi All, I'm wondering what the best course of action is here. I've pulled the skirting boards off the walls to start a redecoration of a room, but now have a crumbling area as shown here:

View attachment 52156

And in a wider view:

View attachment 52157

We think that's cinder block as its a 1930s house. The previous owners had the room replastered and I think they just patched this section after stuffing it with newspaper. The section cracked and bulged into the room after removing the skirting board with a pry tool.

I'm not sure what the best course of action is, at the moment, we're thinking to use two coats of PVA and then mortar to fill the hole before plastering. Any advice or guidance you could offer would be appreciated especially if there is something we absolutely should avoid or something to bear in mind about cinderblock (if that is what this is).

Cheers.
First things first, pull the paper out and check the date on it! It’s the law and just what any experience spread would do.
 

ChrispyUK

Well-Known Member
Hack it back and use bonding after pva. If you’re brave use multifinish but easifil is easier and sandable so better to blend.
 

Cox32

Active Member
Hi All, I'm wondering what the best course of action is here. I've pulled the skirting boards off the walls to start a redecoration of a room, but now have a crumbling area as shown here:

View attachment 52156

And in a wider view:

View attachment 52157

We think that's cinder block as its a 1930s house. The previous owners had the room replastered and I think they just patched this section after stuffing it with newspaper. The section cracked and bulged into the room after removing the skirting board with a pry tool.

I'm not sure what the best course of action is, at the moment, we're thinking to use two coats of PVA and then mortar to fill the hole before plastering. Any advice or guidance you could offer would be appreciated especially if there is something we absolutely should avoid or something to bear in mind about cinderblock (if that is what this is).

Cheers.
Wet it up with brush to get rid of any dust, use bonding coat to fill in hole and bring it out to thinkness of the wall. When it’s dry put skirting board on. And if the skirting board doesn’t cover all the damage area use some easifill then sand it
 

ChrispyUK

Well-Known Member
Why would you use PVA on cinder block, plain water for the mortar.

Ok Pitkin. This type of block work is crumbly and dry as fook, about 50mm thick and is usually built off a timber sole plate. Nothing wrong with using a pva mix on dry block when using bonding or on chases. Hardwall, wet it. Bonding, pva it. My rule of thumb but you could shove some compo in there instead.
 

tapit

Well-Known Member
Ok Pitkin. This type of block work is crumbly and dry as fook, about 50mm thick and is usually built off a timber sole plate. Nothing wrong with using a pva mix on dry block when using bonding or on chases. Hardwall, wet it. Bonding, pva it. My rule of thumb but you could shove some compo in there instead.
(y)
 

fadeout32

New Member
Bigger skirting

Thank's everyone who replied!

This is already part of the plan - we prefer it anyway but the hole is 230mm and we'd use 125mm skirting. Sounds like the consensus is optional PVA then bonding to flush then skirting and filling?

If you look closely you can see the date on the newspapers in the photos, you have to look really close though :p
 

fadeout32

New Member
Ok Pitkin. This type of block work is crumbly and dry as fook, about 50mm thick and is usually built off a timber sole plate. Nothing wrong with using a pva mix on dry block when using bonding or on chases. Hardwall, wet it. Bonding, pva it. My rule of thumb but you could shove some compo in there instead.
Thanks! Out of interest why is mortar not recommended? We already have some so would save us a few bob.
 
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