re: Estimate to build brick and concrete deck

3rd picture is gonna be the cheapest and the number I would pull out of my arse starts at 40k for 900 sf depending on location and goes up from there.

The 1st and 4th were done when the house was built and to do something like that as a renovation would be stupid expensive. The 2nd was an addition like the 3rd.

Not sure if the perimeter foundation has the extra capacity for them to ledger into the 2nd floor framing or if they had to remove some brick and add additional gang studs to that back wall.