Does this look okay for my first rehab?

[Ryan White]

Its listed for $29k but going to offer 10k.

it needs a complete rebuild, floors are gone, including the joists all rot under the walls, termites damage up the wall framing on one end that i can see, roof as well needs replaced. 

the flooring is the main thing im worried about, like do you have to take down the whole frame of the house to replace all the joists?