When frames are fixed on the door ways, a joint is formed in between the timber and masonry. This joint should be covered since timber and masonry do not bond. In buildings, different materials fixed together have joints that require to be covered. In expansion and contraction of different materials a gap will appear. Materials like glass and timber, glass and concrete, aluminum and masonry, glass and steel do not bond and thus a finish is applied on the joints.

When fixing door frames in a building, the passage should allow for a finish to cover the material joints. The design should be at least four feet. This will allow a nibs of four inches to be built on both sides of the door way. The frame is fixed in the remaining distance between the nibs. The door frame may be fixed flush on one side of the nibs. The other side may be recessed at least two inches from the nib ends. Alternatively it is fixed midway on the nibs, thus its recessed on both sides. Read the rest of this entry »