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Bruce[_8_] Bruce[_8_] is offline
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Default butt joining floor slabs

On Tue, 20 Apr 2010 12:01:06 +0100, Tim Watts wrote:

Bruce
wibbled on Tuesday 20 April 2010 11:54

On Tue, 20 Apr 2010 10:41:01 +0100, Tim Watts wrote:

If you do - this trick is fairly easy:

Drill into the side of the old slab at foot intervals and resin-mortar in
some heavy studs (M10-M12), say 4" into the old slab and 4" protruding.
That should provide a good mechanical lock.



That's not anywhere near long enough. Thermal movements, shrinkage
and creep will be enough to break the bond, and the dowel bars (that's
what they are called) will be worthless. I would recommend 200mm into
the old slab and 200mm protruding. Otherwise, don't bother. Also, I
would avoid studs and use plain mild steel bar - not the ribbed kind
either.


Good to know. Do you reckon 300mm spacing is OK?



I have never seen closer spacing. In very large slabs, it is often
wider, but 300mm seems pretty sound for this application.