(A) General requirements. All wood construction shall conform to the requirements of this section.
(1) Minimum sizes of lumber members required by this subchapter refer to nominal sizes. American Lumber Standards for dressed sizes shall be accepted as the minimum sizes conforming to nominal sizes. Computations to determine the required sizes of members shall be based upon the net dimensions (actual size) and not on the nominal sizes.
(2) Splicing of wood joists between bearing points is prohibited.
(3) Girders shall be structural steel, solid wood, built-up wood or reinforced concrete.
(4) All joists of solid wood girders shall be made over pier or column supports. No built-up girders shall have joints broken at less than four foot intervals.
(5) Wood or steel posts when used as columns in basements shall bear on a cement base 24 by 24 by 12 inches. The base shall bear directly on the post footing.
(1990 Code, § 8.10)
(B) Floor, ceiling and roof framing.
(1) Where floor joists frame into the side of wood girders, the joist shall be supported on metal joist hangers.
(2) Ends of floor joists framing into masonry walls shall be supported on metal joist hangers or shall have not less than four inches bearing and shall have at least inches fire cut. An air space of one-half inch shall be provided at ends and sides of wood joist framing masonry.
(3) Floor joists shall have a clearance of not less than 18 inches between the bottom of joists and the surface of the ground underneath. Floor joists up to 13 feet in length shall be at least two by eights placed 16 inches on center, 13 feet to 16 feet shall not be less than two by tens placed 16 inches on center.
(4) Floor joists shall be doubled under all non-bearing partitions which run parallel to the floor joist. Joists under bearing partitions shall be multiplied in sufficient number to adequately support combined loads. Doubled joists shall be separated and blocked at four feet intervals where piping or duct work occurs.
(5) Ends of lapped joists shall rest on girders or on bearing partitions and shall be securely nailed to plate and to each other.
(6) Floors, including attic floors and flat roof joists, shall be cross-bridged at intervals not to exceed eight feet and double-nailed at each end.
(7) Where the structural strength of framing members is definitely impaired by inherent defects or by cutting or drilling, such members shall be reinforced or replaced as required by the Code Administrator.
(8) An opening not less than 24 inches by 30 inches access into each attic space shall be provided.
(9) All attic spaces and other space between flat roofs and ceilings shall be ventilated by screening louvers or other means approved by the Code Administrator.
(10) Ceiling joists up to 14 feet shall be two by sixes; 14 to 16 feet shall be two by eights. When ceiling joists do not serve as ties for the rafters, collar beams of one by six or two by four shall be installed on at least each third pair of roof rafters and shall be securely nailed to the rafters. Maximum spacing of collar beams, five feet on center.
(11) All openings in roofs for dormer windows which are not supported on partitions shall be framed with double rafters and headers.
(12) All rafters shall be at least two by sixes spaced 16 inches on center.
(13) Roof boards shall be minimum three-quarter inch or plywood one-half inch.
(1990 Code, § 8.11)
(C) Exterior walls.
(1) All exterior wood or metal stud walls shall provide strength and rigidity equivalent to the following:
(a) Two by four inch wood studs spaced not more than 16 inches on center for walls supporting floor loads;
(b) Two by four inch wood studs spaced not more than 16 inches on center for walls that do not support floor loads.
(2) Headers over all openings shall be doubled and shall be set on edge. Spans for headers shall not exceed the following for size given.
(a) Spans up to four feet: two two by fours;
(b) Spans four feet to five and one-half feet: two two by sixes;
(c) Spans over seven feet: two two by tens.
(3) In lieu of headers, trussed construction may be used.
(4) The sills of frame walls supported directly on masonry shall be not less than two inches thick and not less in width than that of the width of the studs. Such sills shall be bolted to the masonry at corners and between corners with half inch bolts not less than 11 inches in length and spaced not more than six feet apart.
(5) Sheathing may be of wood, structural insulation board, gypsum board, plywood or other materials approved by the Code Administrator.
(1990 Code, § 8.12)
(D) Interior walls.
(1) All interior walls shall provide strength, rigidity and durability equivalent to the following: two by four inch wood studs spaced not more than 16 inches on center for all interior walls.
(2) All interior walls shall be covered with wood, dry wall, masonry, plaster or the equivalent in strength, rigidity and durability. The following minimums shall apply to the above materials:
(a) Wood - one-quarter inch over three-eighths inch backing;
(b) Drywall - three-eighths inch;
(c) Plaster - five-eighths inch of covering.
(3) Above components may further be covered by laminated or affixed coverings.
(1990 Code, § 8.13)