Bad bricks

[MH731Z]

Hi All

Was not sure how to describe this issue but basically I removed the old rendering and discovered the wall is made up of several types of blocks and bricks as follows

1. very strong concrete blocks
2. very week brcks
3. very weak concrete blocks 'the darker coloured ones'

the wall is a cavity wall but with very small spacing and the other side of that wall appears to be normal bricks, the internal wall however has this weird mix, some images below

the block below is the weaker concrete, i even saw some glass in it, the ones below it are much much harder blocks

so my questions are as follows

1. should I replace those weak, weird looking blocks and if so what would be the best approach ?
2. what is the best thing to use to fill those large holes or space like in the image above ? expanding foam ?

any help or advise is much appreciated!

 

[MH731Z]

some more images below showing the weird mix of blocks and bricks

 

[MH731Z]

anyone ?

 

[Mottie]

If it’s going to be rendered, many people will just use up any old brick/block that’s laying about. Down the end of our road, a builders son has bought a house for himself to live in. He has added a porch and a double height rear extension. Been slowly doing it up over the last two years with his dad helping him. Both the porch and the extension are made up of an assortment of bricks/blocks, probably left over from jobs they have done. You won’t see any of them when it’s finished and rendered.

 

[MH731Z]

If it’s going to be rendered, many people will just use up any old brick/block that’s laying about. Down the end of our road, a builders son has bought a house for himself to live in. He has added a porch and a double height rear extension. Been slowly doing it up over the last two years with his dad helping him. Both the porch and the extension are made up of an assortment of bricks/blocks, probably left over from jobs they have done. You won’t see any of them when it’s finished and rendered.

I see, so it seems to be a thing.

 

[noseall]

anyone ?

Are you plastering it?

 

[Ivor Windybottom]

I'd use mortar with a gun for the holes, after wetting it. Foam could be a bit bouncy for plastering, so may crack.

Wouldn't worry at all about the blocks, they're not falling apart or cracking. They're probably made from ash from an incinerator.

 

[MH731Z]

Are you plastering it?

yes will be using plasterboards and foam adhesive gun to fix them then tape, skim etc

 

[MH731Z]

I'd use mortar with a gun for the holes, after wetting it. Foam could be a bit bouncy for plastering, so may crack.

Wouldn't worry at all about the blocks, they're not falling apart or cracking. They're probably made from ash from an incinerator.

good idea, is the mortar only because of the plastering ? I was thinking of using plasterboard and foam adhesive

 

[Ivor Windybottom]

Plasterboard's not usually attached with foam, it will be too flexible so the joints will all crack.

Fill the holes either way - even if dry-lined you'll get cold spots from the draughts.

 

[noseall]

Plasterboard's not usually attached with foam

 

[Ivor Windybottom]

Great, a bouncy castle in a can.

Plasterboard's bad enough when dotted and dabbed, putting foam under it must make it terrible.

 

[^woody^]

LOL. "Foam" does not mean "sponge".

BTW, it's the 21st Century, get with it.

 

[noseall]

Great, a bouncy castle in a can.

Plasterboard's bad enough when dotted and dabbed, putting foam under it must make it terrible.

Superb at acting as an adhesive medium where foil coated items are concerned.

 

[Ivor Windybottom]

It's full of air bubbles, it's a sponge. I know what foamed polyurethane is like, it's definitely not rigid.

Another of those cases where it's not right but it's OK. Might look alright at first, a couple of years later there will be hairline cracks down every joint as soon as someone leans on it.

I'd just get it wet plastered anyway, can't stand dry-lining myself. Seems a shame to take a solid wall and turn it into something that feels like a newbuild flat, that sounds like a cardboard box if you tap it. Plus you can't reliably fix anything to it, at least not without a major operation. Chasing out for any future additional wiring is pretty much impossible.