Sun Mountain Blog

Using Kerfed Flat Jambs to Create Case-Less Interior Door Openings

Case-less interior door openings (with no case moulding around the door) are growing in popularity, particularly in contemporary and modern home designs.


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Sun Mountain offers kerfed flat jambs to create these case-less interior door openings. Kerfed flat jambs are slotted on the edge for wrapping the drywall corner bead (rounded or even square drywall corners) into the jamb.



These jambs are typically 1” more narrow than regular flat jambs, to allow for wrapping the drywall corner bead into the jamb. The chart below illustrates the proper jamb widths for kerfed flat jambs, to fit standard wall stud widths and sheetrock thicknesses:

                        Stud, Sheetrock Thickness             Flat Jamb Width
                         2×4 Stud, 1/2” Sheetrock                3-5/8” Wide
                         2×4 Stud, 5/8” Sheetrock                3-5/8” Wide
                         2×6 Stud, 1/2” Sheetrock                5-5/8” Wide
                         2×6 Stud, 5/8” Sheetrock                5-5/8” Wide

And, our kerfed flat jambs are available in any wood species sold by Sun Mountain.


To learn more, contact us at 888.786.6861 or visit