Question to Bricklayers

[carryoncamping]

I'm about to use 73mm bricks (a kind of Imperial/Metric hybrid) for an extension on a pre 1960s house.

The blocks will be standard Metric (i.e. 440x215x100mm Which as you know equates to 3x2 metric bricks (215x65x102.5mm )+10mm joints).

I was wondering how you place the walls ties so that they run down away from the inner skin (to reduce damp transfer)? As the taller bricks will get out of "sync" with the blocks.

Are you allowed (BC) to place wall ties in the perps?

Hope the above makes sense!

Cheers
Carry

 

[noseall]

every sixth course, every fifth course, every sixth course every fifth course...........and so on.

 

[tawelfryn]

Make sure you use ties that can bend easily, not the rigid type it will be a nightmare! (stainless steel) Make sure the ties a plenty long enough to bend down a course and still have enough bearing. Place ties on normal when you build the block work, every two courses for insulation to clip, and every course up reveals.
When doing the brickwork, bend ties down the nearest course which you can, to avoid any running up. Ties should not be put in perps.

 

[gangman]

Just finished an extension in Cardiff using imperial size bricks and metric blocks. It can be a bit of a pain messing around with the ties but when you look at the finished job that's all forgotten about and it'll be worth it for the extension to look like its always been there.

You've had some good answers already and there's some tips I can add. Whenever I'm using imperial bricks I build the internal skin of the footings about an inch higher. That helps on the first couple of courses of ties.
When you're matching existing brickwork you're stuck with their gauging and that can be all over the place. If you need to, instead of going two courses of blocks for your ties go one, that can help match the beds up.
I've done a lot of work with the old stock bricks in London, and a few times I've trimmed a course of blocks to match the beds. You just do what needs to be done, it might take more time but it's the end result that counts.

The main place to struggle is up the reveals. Here I use extra ties and get them in the best I can and I have put ties into the perps on the bricks here. The way I look at it it's there's more strength in a tie in a perp than no tie at all or a tie bent down so far it's not sitting in the beds far enough.

You'll have problems with the insulation boards as well. When the ties are bent down the clips don't really hold the board above. Now BCOs are looking for the joints on the boards to be taped so that helps hold them but if I'm not happy with the board I use a 4in screw through a clip and fix into the blockwork.

Best of luck with your job

 

[^woody^]

If you are using an aerated block (celcon, thermalite etc) then you can get helical ties that you knock into the blockwork anywhere you like to match up with the brick courses.

You will not be able to pull these out, they are really good.

 

[carryoncamping]

Thanks for all you informative replies.