Once the drywall is in place, any new soffits can be framed and covered with drywall also. Their usual function is to fill in the open spaces between the ceiling and the tops of the wall cabinets, but they can also be used to hide new plumbing pipes if those are roughed-in outside the wall.
They're typically about 13" wide and 7" or 8" high (with 8' ceilings and 36" high wall cabinets).
The front is usually built by suspending a short wall from the ceiling, and the bottom is framed between that and the wall.
A pair of 2x4 nailing strips are secured first, one to the ceiling and one to the wall but running parallel to each other.
A 2x2 "ladder"-type wall is built on the floor for the front of the soffit, consisting of 2x2 plates, 2x2 plates matching the lengt../store/videos of the nailing strips, and 2x2 studs equal to the soffit height minus 3" for the thickness of the plates.
The studs are nailed between the plates every 16" for proper drywall backing, and the studs are so short the framing ends up looking like a ladder.
The top of the framing ladder is set flush to the ceiling, snug against the edge of the nailing strip, and it's nailed or screwed into it to secure it solidly. (Using screws is often preferred because there's less stress on the existing structure.)
2x2 "lookouts" (short, horizontal framing members) are cut to frame the bottom of the soffit, extending from the bottom of the nailing strip on the wall to the bottom of the front of the soffit, and they're secured by nailing or screwing up through their ends into the nailing strip and the front of the soffit.
The soffit framing can then be covered with drywall.
TIP: If you have to drill into the drywall or ceiling after the soffit is up, be sure to firestop the hole with gypsum board, tightly-packed insulation or mineral fiber.
Finishing Drywall Joints
You can usually figure on three separate applications of joint compound to finish the new drywall joints.
Fill each joint with compound, feather it out a couple inches each way and embed fiberglass mesh tape or paper tape in it. Also cover the screw and nailheads, filling the dimples and scraping away the excess. Let the first application dry overnight, unless you're using a quick dry formula—then follow package directions.
Before starting, use a drywall knife to scrape off any ridges left on the first application. Then spread more joint compound over the first application, spreading the compound thinly beyond the dried edges an inch or so. You're basic goal is to hide the inevitable build-up of compound by feathering it out across the surface, while filling any gaps left by the first application. Let the second application dry.
Scrape off any new ridges left after the second application, and then spread out your third layer of compound, feathering it even further this time. Let that application dry, sand it with a drywall screen and coat the surface with a good primer-sealer. Then you're ready for cabinets.
For more information please visit our Finishing Drywall Section