Abstract: Wood trim is attached to the wail around a door, window, etc, by means of an extruded plastic attachment strip. The strip is formed with a hollow box-shaped protrusion which serves as a spline, which engages a complementary groove in the profile of the wood trim. A bar formed in the back of the strip profile serves to hold the strips in complementary slots in the door jamb.

Abstract: Door frames, window frames, baseboards etc are trimmed with solid weed, e.g. oak, trim pieces. The trim pieces are fitted over splines which are screwed to the wall. A jig enables the splines to be located accurately in position. The spline includes no beads, snaps, or other features that would require the oak trim section to flex; instead, the trim is secured by the friction arising from the fit of the spline into a groove cut into the rear face of the trim section. In a variation, a pair of parallel grooves are provided, together with a corresponding pair of splines, which are mounted on a web.