DR Danise, It is possible Mr. B is an escape artist & that is why he was running free. I wonder if he will return. Did you have a tag on the collar? If you want a call on him I suggest letting the shelters know in case he shows up there. Did the workmen have any idea what time he disappeared? Wherever he is, I wish him well.
I'm sorry about the roof & agree with DR Jose, make sure you have a guaranteed amount, in writing & signed by him, the contractor may not go over.