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Bricklaying & Repointing

73mm bricks 215 blocks courses out

Anonymous user 26/02/2026 - 10.21 AM

Hi all, I'm building a side extension and I'm using the same height bricks as what's on the existing property (73mm) Ill also be using 215 solid blocks on the inside skin.. My question is, because the bricks are 73mm tall, by the time it comes to putting the cavity wall ties in the courses dont line up,, using 10mm mortar gaps the first wall tie inserted on the second block course would be 48mm out, then the next course would be 96mm out then 144mm. Without bending the wall ties down that far what other options would you all suggest? Thanks..

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8 Answers

Pete Nash

Rating: 5 out of 5
Barnstaple
I take the existing brick work is old , this will be because their imperial , and blocks today are metric . theirs no way of doing this except, for bumping the block work beds up to gain the mms needed .
Answered19 February 2026
7

Bricky ste

Rating: 5 out of 5
Liverpool
Hi, as someone else has said it's a unavoidable small problem. U could make the blockwork beds bigger and try to compensate for the difference between the bricks and blocks. But me personally would keep everything the correct gauge, (unless your toothing into the house brickwork which will more than likely be bigger mortar beds anyway as a lot of old stuff is.) I generally find that I have to use a tape measure to measure the closest to 450 mm as this is what the ties should be. And if you have to bend the ties slightly that's fine, just try to make sure they bend downwards to the brickwork so any water doesn't ever fall back towards the inside of the house. Slightly long winded but always difficult to explain in writing. Hope this helps.
Answered1 October 2019
5

James Building Services

Rating: 5 out of 5
Birmingham
As stated in previous posts the bricks are imperial and blocks are metric a small fall on the ties will not create any problems alternatively bed joints on block work should be increased to suit brickwork hope this helps
Answered21 October 2019
2

MV Build It

Rating: 5 out of 5
Oldham
From the damp course your tie wires should be every 450mm , so if you measure up and put the ties to the nearest courses at 450 then 900 then 1350 then 1800 and so on as long every 450mm you will find that some will tie on ok with the block work 👍
Answered29 September 2019
1

Michael Bradfield building services

Rating: 5 out of 5
West Drayton
Do bigger beds on the block work to match the brickwork
Answered27 September 2019
0

SK Builders

Rating: 4.5 out of 5
Coventry
Put the ties every 6(498mm) course and inside the 2 course of blocks put a slip brick to get 500mm. Problem solved 😉
Answered11 February 2026
0

Martyn Perrin

No reviews yet

Guildford
Adjust Block Course Height Use 10-12mm mortar beds on blocks instead of standard 10mm This gives you flexibility to "catch up" with brick courses every few rows
Answered11 February 2026
0

Petru Guriuc

Rating: 4.9 out of 5
Hounslow
When you’re mixing 73mm bricks with 215mm blocks, the courses almost never line up perfectly, that’s completely normal. What most bricklayers do is tweak the internal block bed joints slightly (within reason) to help bring things back in line over a few courses. You can also run slightly thinner bed joints on the blockwork where needed to reduce the difference gradually. The main thing is not to force the wall ties by bending them excessively. Just keep them at the correct spacing spec: around 450mm vertically and 900mm horizontally, closer around openings, and build them into the nearest suitable bed joint as you go. They don’t have to sit exactly opposite each other course for course. In short, focus on correct tie spacing and good practice, not on making the brick and block courses match perfectly, because with different brick heights they rarely ever will.
Answered26 February 2026
0