In article .com
, Weatherlawyer writes

wrote:
We're planning to replace our existing conservatory with a more modern
"glass box". The conservatory has some fairly major concrete
foundations, but the box would be a different size and therefore the
foundations won't do. Is it possible simply to extend those foundations
by a metre or two (horizontally - the height/depth needn't change), or
do they need to be complete dug up and replaced?

Just drill it for rebar. I have no idea where you'd get that from nor
the size you'd need. Use an SDS to zig zag a few in. They need to be
tight without splitting the concrete. Maybe find some sort of nylon
sleeving?

Resin bonding them in would probably be the way to go:
http://www.screwfix.com/app/sfd/cat/pro.jsp;?id=42772 , I'd put the holes
in straight too, three or so at around 10/12mm dia if putting down a little
reinforcement in the new strip.
--
fred
Plusnet - I hope you like vanilla