"Bob" wrote
We want to add on to our antique farmhouse. We would like to do a 24x24
1st floor addition. Much of this space will be family room, but should
it have a cathedral ceiling or traditional ceiling with unfinished
space above it?

Our debate is whether we should do just a cathedral ceiling over that
family room, or make the ceiling normal and then add a bonus room over
that, which would tie into the existing 2nd floor.

We know it would be more to do the 2 floors, but does anyone know about
how much more?

Part of the reason for cathedral ceiling is asthetic. But also, it is
to save money on framing for a potential 2nd room above the family
room. We would go ahead and spend the extra money to have the bonus
room only if the price differential is small. If cathedral option saves
big $, we'll opt for that.

[Also, as far as resale value goes, does anyone know whether it would
be more desirable to have that bonus room and regular family room
ceiling, versus just the family room with cathedral ceiling?]

Would appreciate any feedback you might have! Thanks.

Your question would be better answered by a local designer with proven
experience.
Some areas won't allow an unfinished 2nd floor.
You'll need to install a stairway to access the 2nd floor, which will reduce
the floor space on the 1st floor.
A stairway is roughly about 4' x 12'.
If you are required to finish the 2nd floor prior to the issuance of a
certificate of occupancy this will entail additional HVAC, Plumbing and
Electrical, as well as doors, subdividing walls and perhaps even egress
windows if there are any sleeping rooms on that level. In addition the
footings as well as 1st floor walls will need to support the 2nd floor, all
of which cause the costs to skyrocket.
Consult local professionals.