extension planning - what comes first...?

[Fender1]

2016 is the year that I want to get the house of my dreams. We have a flat roofed double garage ( integral to house) plus kitchen at rear and want to put two beds plus bathroom above these and also a single extension to the rear of the property.

My question is this:
I know roughly what I want and the rough £/m2 price but do I get a builder on board before an architect or someone else to draw up the plans? It'll need p permission too so we'll need to do a bit of homework I reckon.

What have others done in similar situations?

A builder can only give you a very rough idea of the cost if you don't have plans to show him.

I would get an architect (or ideally a good technician) to draw up some plans for your planning permission and go from there. I would also dig a trial hole and get your local building control to come and inspect your foundations (or the structural engineer involved). If they are inadequate to take the second storey - it can have a massive impact of the cost of the works.

Thanks, that feels natural to engage an architect/ technician early and get something down on paper.

Also good point re checking existing foundations.