tying in extension walls

[sm_jamieson]

I have to build an aircrete wall and cavity against a brick party wall. The party wall is 9" thick up to around 2 metres high, where it changes into a single skin on the neighbours half of the party wall, and next-doors ceiling joists fully penetrate this skin. I filled in the gaps around these joists with foam when I demolished my old out- house. I intend to tie in a new wall that is 90 degrees from the party wall using a wall starter system. What I need to do is modify the upper section so it is effectively a

9" wall in order to properly isolate next door from the cavity. I probably cannot chop out bricks from her wall in order to form a standard bond with regular headers etc.

So what is the best way of tying in a new skin to to create a 9" wall to the satisfaction of the BCO ? Bearing in mind that this new skin will then further become one side of a cavity wall (i.e. it will be tying in 2 directions).

Thanks, Simon.

[4square]

I would advise, have a word with the BCO who covers your area, probably not the first time this has arisen, and they ought to be able to help on details like this. It may even be covered in one of the approved documents. Best to sort all these sort of details before starting work, no nasty surprises then!

[The Natural Philosopher]

Sounds like raking out a little mortar and inserting 'bow ties' to me, but ask BCO for sure.

[Phil L]

short screw-in ties, stainless steel, or galvanised. If you intend building the skin from bricks, the ties will have to go in the horizontal joints, but if you build it from block, they go into the bricks themselves, which makes a better job....make sure you use short ones or they may burst through to next door.

[sm_jamieson]

bricks ? I cannot visualise this. I will build most of the skin out of blocks, some brick at the end, where they would show. Simon.

[Tournifreak]

If I've understood you corectly, this is what you need...

[sm_jamieson]

Actually, yeah, I could just use several of those, both for the 90 degree wall and to tie the single skins together. I'll discuss the options with the BCO. Cheers, Simon.

[Phil L]

The screw in ties fix better to bricks than to mortar, so it's best to space the blocks so that they don't line up with the horizontal joints of the brickwork..there's a small pic here:

may have to start off with a piece of block first so that the spacings are correct, thermalite are easy to saw using an old handsaw.