average thickness of floor joistst
Floor Joists. The floor joists comprise the bulk of the floor thickness. Standard floor joists are usually 2-by-10 or 2-by-12 dimensional boards, installed on edge. The actual width of those boards, however, isnât identical to what their name implies.A 2-by-10 joist is really only 9 1/4 inches wide and a 2-by-12 is only 11 1/4 inches wide, so depending upon which size joist the blueprints call for, they will add the respective measurement to the thickness of the floor.Subflooring only adds 3/4 inch to the floor thickness.he actual width of those boards, however, isnât identical to what their name implies. A 2-by-10 joist is really only 9 1/4 inches wide and a 2-by-12 is only 11 1/4 inches wide, so depending upon which size joist the blueprints call for, they will add the respective measurement to the thickness of the floor.