Door Jambs

A pre-hung door is a complete unit, with the door frame (or “jamb”), hinges, and door stop, preassembled for quick and easy installation. This ready-to-install solution eliminates the need for on-site assembly, saving time, reducing labor costs, and streamlining the construction process.

Sun Mountain not only crafts premium-quality doors but also offers expert factory pre-hanging. Hinge pockets are precisely mortised for a flush fit, ensuring the door hinges squarely within the frame. Hinges are included and available in a variety of metal finishes. We also provide hardware prep at no additional charge, including boring and latch/deadbolt fortising, with the option for single or double bore in various “backset” positions (distance from the door edge to the hardware).

Factory pre-handing guarantees a clean, consistent reveal (the small, even gap between the door and jamb when closed) for a polished, professional fit. While we offer a full range of standard jamb options, custom jamb designs and sizes are available on request.

For a free, no obligation quote, contact Sun Mountain at 888-786-6861 or sales@sunmountaindoor.com

Jambs for Interior Doors

Flat Jambs With Adjustable Stop

For interior doors, Sun Mountain offers solid wood flat jambs with an adjustable stop. If the door is ordered with a factory-applied wood finish, the jambs and stop are finished separately, allowing for easy on-site adjustment without the need for finish touch-ups.

Kerfed Flat Jambs

Sun Mountain also offers solid wood “kerfed” flat jambs. A kerf is a slot cut on the edge of the jamb, used for wrapping the drywall corner bead (square or rounded drywall corners), creating a clean, “caseless” opening where the drywall meets the door frame directly, eliminating the need for case mouldings. Kerfs can be applied to one or both sides of the jamb (as shown).

When pre-hung interior doors are finished in the factory, Sun Mountain includes finishing of the jamb at no additional cost. The adjustable stop is finished separately for field adjustability.

Jambs for Exterior Doors

Rabbeted Jambs

Exterior doors require durability, which is why Sun Mountain frames them with solid wood rabbeted jambs featuring a non-adjustable stop cut directly into solid wood. A  Q-Lon® weatherstrip is inserted into a kerf along the stop, creating a tight seal around the top and sides of the door to limit air transfer and protect against the elements.

Kerfed Rabbeted Jambs

For a cleaner, more integrated look, Sun Mountain also offers kerfed rabbeted jambs. Typically, the kerf is applied to one side only on the interior face of the door frame (as shown).

Sills

Sun Mountain’s pre-hung exterior doors also include a standard aluminum adjustable door sill, available in Mill (aluminum) or Oil Rubbed Bronze finishes, and configured for either inswing or outswing doors, all at no additional cost.

Additional sill options are available, including ADA-compliant sills, wood sills, and hydro sills (recommended for double doors; additional cost applies).

Sweeps

Factory-prehung doors from Sun Mountain include either L-shaped or surface-mount door sweeps with built-in drip caps to divert water. L-shaped sweeps are standard on all 1-3/4″ doors; surface-mount sweeps are used on 2-1/4″ or thicker. If installed on-site, we recommend sealing the top edge of the sweep with silicone to prevent moisture.

BRICK MOULDING

Sun Mountain includes standard 2″ wide x 1-1/16″ brick case moulding with eased edges (E2E) on all pre-hung doors at no extra cost (excluding radius moulding). Additional decorative profiles and stucco mouldings are also available, free of charge, except for radius versions.

Jamb WIDTHS

Door Jambs must match the full wall thickness, accounting for both the stud and sheetrock. Most walls are framed with either 2×4 or 2×6 studs and finished with ½” or ⅝” sheetrock. To ensure a precise fit, determine your wall components and refer to the charts below to select the correct jamb width.

INTERIOR JAMB WIDTHS

Flat interior door jambs are available in the following widths, to match the following wall stud and sheetrock thicknesses: 

Flat Jamb With Adjustable Stop

Kerfed (both sides) flat jambs for interior doors are available in the following widths, to match the following wall stud and sheetrock thicknesses: 

Kerfed (Both Sides) Flat Jamb with Adjustable Stop

STUD, SHEETROCK THICKNESS	JAMB WIDTH
2×4 Stud, 1/2” Sheetrock	3-1/2” Wide
2×4 Stud, 5/8” Sheetrock	3-1/2” Wide
2×6 Stud, 1/2” Sheetrock	5-1/2” Wide
2×6 Stud, 5/8” Sheetrock	5-1/2” Wide

Kerfed (one side) flat jambs for interior doors are available in the following widths, to match the following wall stud and sheetrock thickness:

Kerfed (ONE Side) Flat Jamb with Adjustable Stop

STUD, SHEETROCK THICKNESS	JAMB WIDTH
2×4 Stud, 1/2” Sheetrock	4-1/16” Wide
2×4 Stud, 5/8” Sheetrock	4-3/16” Wide
2×6 Stud, 1/2” Sheetrock	6-1/16” Wide
2×6 Stud, 5/8” Sheetrock	6-3/16” Wide

Exterior JAMB WIDTHS

Rabbeted jambs for exterior doors are available in the following widths, to match the following wall stud and sheetrock thicknesses:

Rabbeted Jamb

STUD, SHEETROCK THICKNESS	JAMB WIDTH
2×4 Stud, 1/2” Sheetrock	4-5/8” Wide
2×4 Stud, 5/8” Sheetrock	4-7/8” Wide
2×6 Stud, 1/2” Sheetrock	6-5/8” Wide
2×6 Stud, 5/8” Sheetrock	6-7/8” Wide

Kerfed (one side) rabbeted jambs for exterior doors are available in the following widths, to match the following stud and sheetrock thicknesses:

Kerfed (One Side) Rabbeted Jamb

STUD, SHEETROCK THICKNESS	JAMB WIDTH
2×4 Stud, 1/2” Sheetrock	4-1/16” Wide
2×4 Stud, 5/8” Sheetrock	4-3/16” Wide
2×6 Stud, 1/2” Sheetrock	6-1/16” Wide
2×6 Stud, 5/8” Sheetrock	6-3/16” Wide