I don't have the extension issue but I'm having about 475 s.f. of concrete poured next week. It involves a bit of excavation so they have a bobcat in there today. They think it will be about 3 or 4 days of work to excavate, set up the rebar (is that how you spell it?), pour and then come back and do an acid stain and some simple scoring. I think we are around $10 s.f. for that. I did a bit of shopping around and that seemed fairly consistent. Concrete prices are up, I'm told.