Block work doesn’t align

acurachris · 12 Nov 2018

Hi

I’ve realised an issue with my extension and hoping for a little input.

The building officer has said to cut the brickwork vertically to open the cavity up and I can then tooth the brickwork. The bricks under the lintel (pictured) will then be removed and blockwork rebuilt under it and joined to new.

However, I’ve only just realised that the old cavity is 50-75mm and new is 100mm so the block work isn’t going to align!

It means they’ll be a 25mm or so offset on the join, is this okay or does anyone have a better way?

Ajjax · 12 Nov 2018

Leave the bricks in place, use a wall starter for inner leaf, cut a vertical DPC slot and put some straps across?

acurachris · 13 Nov 2018

Ajjax said:
Leave the bricks in place, use a wall starter for inner leaf, cut a vertical DPC slot and put some straps across?

Thanks for replying, although, the BCO has already said those bricks should be taken out. There was an extension here previously which was just butted up (no ties or anything) to the wall. I was wondering if offsetting the new blocks to the existing by 25mm would cause an issue.

I'm not sure there is another way really (thinking about it), just wondered if this has come up for someone else.

garyo · 13 Nov 2018

I've had this twice. You should remove the bricks for thermal bridging reasons as well as damp, then it's up to you whether to use wall starters or toothing in.

The 25mm step is unavoidable. In the past I've a) hidden it with lucky placement of kitchen units or b) dot and dabbed a layer of insulated plasterboard on to the old building to level it all out.

acurachris · 13 Nov 2018

garyo said:
The 25mm step is unavoidable. In the past I've a) hidden it with lucky placement of kitchen units or b) dot and dabbed a layer of insulated plasterboard on to the old building to level it all out.

Yeah i'm fine with the wall not being level on the inside, because as you say, that can be hidden with plasterboard or something. It just feels somewhat of a bodge to not have the walls in a straight line

. So long as it's acceptable and won't affect the strength of the wall, then i'll do that.

Cheers

cAtLeYx · 17 Nov 2018

acurachris said:
Hi

I’ve realised an issue with my extension and hoping for a little input.

The building officer has said to cut the brickwork vertically to open the cavity up and I can then tooth the brickwork. The bricks under the lintel (pictured) will then be removed and blockwork rebuilt under it and joined to new.

However, I’ve only just realised that the old cavity is 50-75mm and new is 100mm so the block work isn’t going to align!

It means they’ll be a 25mm or so offset on the join, is this okay or does anyone have a better way?

View attachment 152137 View attachment 152138 View attachment 152145

Prop the lintel, remove the face brickwork to the left hand side of the opening, construct outer face of brickwork toothed into the existing, reduce your cavity on this elevation to a full fill 50mm and then your inner leaf will line up and you've removed any risk of cold bridging.

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Block work doesn’t align

acurachris

Ajjax

acurachris

garyo

acurachris

cAtLeYx

DIYnot Local

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