Extending existing garage base?

[blue8]

Hi, I'm playing with the idea of pulling down our old and distinctly knackered (flaky panels, rusting ties) sectional concrete garage and rebuilding in blockwork with a straightforward flat roof.

Ideally, I'd like to increase the width of the garage at the same time but this would require a wider base than the existing garage stands on. (I should add that the base is in considerably better condition than the garage.)

My questions then; Is extending a garage base feasible in the first place? Is it necessary to tie in an extension to the base with the existing part? How might this be done?

I've found no shortage of information on laying foundations and floor from scratch, and as far as I can tell the existing base will happily support a blockwork structure, but this has stumped me, and any advice or ideas would be welcome.

 

[^woody^]

I don't think its worth tying in the new to old.

Just make sure the sub-base is well compacted, and form a proper 12mm movement joint with fibre board and a polysulphide mastic seal

If you want to tie the slabs in, you would use dowel bars about 500mm long and 15-20mm diameter, with a sleeve in the existing slab and set into the new one