That works fine, you just have to take into account the jamb when building the
flat.
Sometimes I think the only reason we TD's exist is to make sure door's are properly installed in door flats. I've made the mistake many times, on
working drawings, of simply putting the rectangle in and putting the door dimensions simply to have a carp frame a hole in the
flat to those exact dimensions, forgetting to take into account the
thickness of the jamb and the
swing allowance of the dor and hinges. I, typically, install my doors directly into the flats using the 1x4 as the jamb. This works well for door that are opening onstage or towards the "front" of the
flat. Usually you install a door that opens offstage or towards the back of the
flat with a little more framing support as, unsupported, the 1x4 or 6 will flex too much and
throw off the geometry of the door.
The true "old school" way of installing doors in flats < flown/stationary broadway style flats> was to construct the wall with an opening in it. When the wall was flown in, or moved onstage a carp would run to the door way with a door
unit in
hand. A door
unit would be the Jamb with a
casement molding attached to it and the door hung in it. The jamb would be kept open on the bottom by a "
Sill Iron" sometimes called a "saddle
iron". The
Casement molding would have either bolts or
lag screws poking through it, these would
line up with holes in the
flat which would allow the carp to place the door
unit, then tighten it in place with
Wing nuts from the offstage side.
I'll try to get all these terms installed in the Wikki ASAP with some pictures and stuff.