Extending concrete slab

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Dave65
Posts: 9
Joined: Tue Aug 02, 2016 4:07 pm
Location: Edinburgh

Post: # 111790Post Dave65

I've laid a slab to support a retaining wall. The wall has not been built yet. The slab has a dog-leg and the wall was going to follow the path of the slab. I have now removed the obstacle that necessitated the dog-leg and now wish to build the wall in a straight line. This will mean adding the 'extra' bit of slab.

My original plan was to expose some of the steel work in the slab already laid and tie the steel in the extra slab to this. Having read a bit I'm not so sure that this is the right thing to do.

I've attached a picture (with dimensions) showing both the original dog-leg proposition and also my preferred option with with the 'extra' slab.

I have 2 questions:

1) How should I 'join' the extra slab to the existing slab? Butt up against it? Some sort of expansion joint? Something else? And if the two slabs can move relative to each other, is my wall likely to crack?

2) where the slab(s) meet my neighbour's property, should I avoid the slabs touching their property?

Any help much appreciated.
Many thanks, Dave

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seanandruby
Site Admin
Posts: 4713
Joined: Mon Jun 26, 2006 11:01 am
Location: eastbourne

Post: # 111791Post seanandruby

Drill into existing concrete 200 centres an fix in place with ec410 or similar.You'll need to scabble existing slab. Where foundations meet neighbouring property use 2x20 ml fibreboard, or somethig to create a movement joint. If more than a metre high you'll need a structural engineers advice.
sean

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