Joining Brickwork

[me]

I've noticed a couple of brick-built extensions being built near by and was struck by the fact that the new walls are just being butted up against the old - ie brickwork not being interleaved. (I guess there may be pins of some sort being put in which I can't see)

I certainly wouldn't do it this way myself - are there not any regulations governing this type of joint?

[Brian Sharrock]

The 'modern' way seems to utilise wall tie kits, such as

vertical channel is attached to the 'old' wall with connectors (at right angles) bonded into the 'new' wall.

[Grunff]

The standard way of doing it is to use wall ties, like this:

are very effective, and much less work than toothing in.

[Tony Bryer]

That's now the preferred method, though there should be some sort of toe between the extension and existing house - usually a metal channel 'Furfix' or similar. Bonding in is fine until there's a bit of differential movement between the already settled but (generally) shallow foundation house and unsettled deeper foundation extension.

[Chris Bacon]

Hm. What was "dg" saying a while ago about the "modern requirement for massive foundations v. existing foundations". Hmm.

[dg]

Its the modern way, and the idea is that the metal bolt-on "wall starters" will accomodate movement of the new work.

However, two things which come to mind are -

1. A properly tied in new wall will resist normal movement just as well. If there is so much movement of the new work that it cracks a toothed joint, then there are problems with the foundation anyway, and the joint is the least of your worries.
2. The joint of the wall starter is supposed to be pointed with polysulphide mastic, so that any movement leaves a sealed joint. But

95% of the time this is just pointed with mortar and cracks after two days due to shrinkage

dg

[Andy]

I have just used the Screwfix Wall Starter to tie in a new block wall to an existing pier, all very easy. The points to remember are to use stainless steel wall ties if the job is an exterior wall, and to screw the wall tie rail into the existing brickwork, not mortar joints.

Much, much easier than trying to dog in a block wall to an existing pier.

Andy.

[sourpuss]

The bolt on fir fixes allow some movement, should the new foundations settle even 1mm the joint won't crack unlike if the bricks were interwoven. Cheers. Martin