door jambs

Sun Mountain offers the value-added option of purchasing pre-hung doors, ready to install in the door opening. Our frames, called “door jambs”, are manufactured from solid wood and are available in widths, thicknesses and styles to meet all needs.

Interior doors are generally hung on flat jambs with an adjustable door stop. The kerfed flat jamb, is an alternative more narrow interior frame style. It has slots on one or both edges for wrapping the drywall corner bead into the jamb, providing for a clean opening without case mouldings.

Exterior doors and fire doors are generally hung on rabbeted jambs, a thicker solid wood frame with the door stop cut or built directly into the jamb. The stop is generally kerfed, or slotted, for weatherstripping. For fire doors, our wood jambs can be manufactured to achieve 20-minute, 45-minute or 60-minute fire ratings.

Jamb widths are determined as follows:

Application	Jamb size
2x4 wall with 1/2" drywall	4-5/8"
2x4 wall with 5/8" drywall	4-7/8"
2x6 wall with 1/2" drywall	6-5/8"
2x6 wall with 5/8" drywall	6-7/8"

In Drywall-wrapped Applications	Jamb size
2x4 wall with 1/2" drywall	3-1/2"
2x4 wall with 5/8" drywall	3-5/8"
2x6 wall with 1/2" drywall	5-1/2"
2x6 wall with 5/8" drywall	5-5/8"