Lathing and Plastering.

(1) 

Permit for Plastering. Before any person, firm or corporation shall commence work on any inside plastering or outside stucco or inside dry walling, a permit shall be obtained from the Building Inspector; provided, however, that no permit shall be required for any job for inside plastering or dry wall work not exceeding one hundred (100) square yards. When under this subsection permits are required for inside plastering or dry walling, a fee shall be charged in accordance with Section 13.255 of this Code. The cost of inspection on outside stucco shall be included in the fees provided for under the applicable Section 13.255.

(2) 

Walls and Partitions. The surface of all walls and partitions back of any wainscoting in any building hereafter constructed, enlarged or repaired shall be plastered with at least one coat of plastering of three-eighths (3/8) inch or more in thickness, unless such wainscoting is placed against a fireproof wall.

(3) 

Wood Lath. Wherever wood lath is used as a plaster base, said lath shall be not poorer than No. 2. Such lath shall have an average of not more than one and five-eighths (1 5/8) inches in width and not less than three-eighths (3/8) inch in thickness. Both ends of the lath must have at least an inch of firm wood for nailing. The corners of every room lathed with wood lath shall have corners reinforced with expanded metal lath extending at least four (4) inches each way from the corner. The gauge of the metal from which the lath is expanded shall be no lighter than twenty-five (25) gauge.

(4) 

Key Lath Joints. All ceilings, studding, partitions and furred walls of all buildings, when plastered with lime mortar on wood lath, shall have not less than a three-eighths (3/8) inch key and the ends of the lath shall not be crowded tightly together. Joints shall be broken at least every seventh lath.

(5) 

Three-Coat Work. Wherever three-coat plastering work is to be done, there shall be provided, on all partition and wall openings, three-quarters (3/4) inch grounds, or the frames shall be set projecting three-quarters (3/4) inch outside the face of the studding, said grounds or frames to be of substantial construction and set true and straight. Lath shall in no case be used as grounds.

(6) 

First or Scratch Coat.

(a) 

Ingredients. The first or scratch coat of all three-coat work shall be at least equal to the following: The line shall be of the best quality, evenly and thoroughly burned limestone; the sand shall be of angular grains, sharp, properly screened and free from loan or other deleterious substances; the hair binder shall be water-soaked, well beaten, clean, long winter hair, or approved vegetable fiber cut in two-inch to three-inch lengths may be used for such binder.

(b) 

Mixture. The mortar for the first or scratch coat shall be mixed in the proportions of one barrel of lump lime, two and one-half (2-1/2) barrels of clean, sharp sand, and the binder in the proportion of two (2) pounds of hair on three (3) pounds of fiber to one hundred (100) pounds of lump lime. Said coat shall be well keyed into the lath and shall be at least three-sixteenths (3/16) inch thick. It shall be scored to scratch with diagonal lines in two directions nearly through the thickness. The lime shall be thoroughly slacked, the putty being allowed to cool before incorporating the hair, to avoid burning. The sand shall then be added and thoroughly mixed, and the mortar banked for at least one week before it is applied.

(7) 

Second or Brown Coat. The second or brown coat shall be at least one-quarter (1/4) inch thick and shall not be applied until the scratch coat is dry and it shall be brought to a true plane. The mortar shall be composed of one barrel of lump lime to five (5) barrels of sand with binder in proportion of one (1) pound of hair or fiber to one hundred (100) pounds of lump lime. The mortar for said brown coat shall be prepared as for the scratch coat and banked for at least one week before it is applied. This thickness of the first two coats of plaster shall not be less at any point than one-half (1/2) inch measured from the outside of the lath.

(8) 

Third or Finish Coat. The third or finish coat shall be the best quality of prepared finish or well slacked lime putty gauged with plaster of Paris, or plaster of Paris with marble dust or white sand in combination. The mix shall be proportioned one part of plaster and two (2) parts of white mortar. The lime shall be thoroughly slacked in a box, mixing in a small proportion of white sand or marble dust. It shall then be run through a No. 10 mesh wire sieve into a storage box and allowed to stand at least forty-eight (48) hours before gauging with plaster of Paris and applying. Hydrated limes of approved brands may be used in place of lump lime. The third coat, when finished, shall present an even and true surface.

(9) 

Cornices or Coves. All cornices or coves shall be run straight, true and smooth.

(10) 

Patented or Hard Wall Plaster. Patented or hard wall plasters shall be of brands approved by the Building Inspector and shall be received at the scene of building operations in the manufacturer's original packages and shall be mixed and applied in accordance with the manufacturer's specification. The lath shall be spaced not less than one-quarter (1/4) inch apart, joints to be broken at least every seventh lath, leaving a space between ends of lath. Patent or hard wall plasters shall be applied promptly after mixing, and with sufficient pressure to form a good and sufficient key or clinch on the opposite side of the lath.

(11) 

Two (2) Coat Work. Lath shall in no case be used as grounds. All grounds or jambs for two (2) coat work, where patent plasters are used, shall be of substantial construction and shall project beyond the face of the studding or wall three-quarters (3/4) inch. Where wood lath are used for such work, they shall be spaced not less than one-quarter (1/4) inch apart, with joints broken at least every seventh lath. The proportions of the materials for two (2) coat patent plaster work shall be the same as specified by the manufacturer of the plaster and shall be applied promptly after mixing with sufficient pressure to insure a good key or clinch on the opposite side of the lath. The first coat shall be straight, true and square to the floor line, leaving an even and regular surface, and the second coat shall not be applied until the first coat shall have thoroughly set. The thickness of the two (2) coats shall not be less at any point than three-eighths (3/8) inch, measured from the outside of the lath. All white mortar finishing coats, on any kind of plastering work, shall be laid on and troweled or floated to a smooth surface leaving, on completion, neither deficiencies nor brush marks.

(12) 

Plastering on Plaster Board. No plaster board or sheets of composition board shall be used as a plaster base until the same have been approved by the Building Inspector for such use. Where plaster board or sheets of composition board are used for plaster base, it shall be nailed not further than four (4) inches center to center of nails on every stud or joist.

(13) 

Plastering on Metal Lath.

(a) 

Three (3) coat Work. In all cases where plastering is applied to wire or metal lath, said plastering shall be three (3) coat work, consisting of a scratch coat, brown or second coat and finish coat, the finish coat to be put on as desired by the owner.

(b) 

Fabricated Material. No fabricated material intended for a base to receive exterior stucco or interior plaster shall be used until the same shall have been approved by the Building Inspector for such use. Any such fabricated material to be used must be constructed or fabricated in accordance with approved engineering principles and must have a tensile strength not less than that of twenty-four (24) guage expanded metal weighing three and four tenths (3.4) pounds per square yard and must have rust-resisting qualities equal to those of galvanized metal lath.

(14) 

Plastering Concrete Work. Where plastering is applied to concrete work, the concrete shall be thoroughly cleaned, chipped, scored or dashed with Portland cement and sand before the plastering is done. Wherever unsanded patent plaster is used, the proportion of plaster to sand in the mix of the first or scratch-coat shall be not less than one part of plaster to one part of sand and such plaster shall be so applied as to thoroughly cover all concrete work to which it is applied.

(15) 

Exterior Cement Stucco.

(a) 

Expanded Metal Lath. Expanded metal lath shall be used for exterior stucco work. It shall not be less in thickness than No. 24 U.S. Standard Gauge and shall weigh not less than three and four tenths (3.4) pounds per square yard; and, whenever woven wire lath is used for such work, the wire used in the manufacture of wire lath shall not be less in thickness than No. 23 U.S. Standard Gauge and shall weigh not less than three and four tenths (3.4) pounds per square yard. All metal and wire lath to be fastened on with galvanized staples not less than one inch in length and spaced not more than six (6) inches apart vertically and not more than twelve (12) inches apart horizontally. All such lath shall be painted or coated with rust-resisting materials.

(b) 

Furring. Wherever non-furring lath, consisting of expanded metal or woven wire lath, is used for stucco work, furring at least one-quarter (1/4) inch in thickness shall be properly fastened to the outside walls in a vertical position, said furring to be spaced not more than twelve (12) inches on centers.

(c) 

Three (3) Coats Needed. Except as provided hereinafter for patented exterior stucco, all exterior cement stucco work shall consist of three (3) coats: first, a scratch-coat; second, a brown coat; and, third, a dash or finish coat.

(d) 

First Coat. The first coat of all stucco work shall consist of one part Portland cement and two (2) parts of sand, and sufficient hair or other approved fiber shall be added thereto to properly bind the mortar. Provided, however, that not to exceed ten (10) pounds of lime putty may be added to each sack of Portland cement, at the discretion of the designer or owner. Said first coat shall be properly scratched with diagonal lines in two (2) directions, nearly through its thickness and shall be thoroughly set before the second coat is applied.

(e) 

Second Coat. The second coat shall consist of one part Portland cement and not more than two and one-half (2-1/2) parts of sand. No lime shall be used therein and said second coat shall be thoroughly set before the third coat is applied.

(f) 

Third Coat. The third coat shall consist of one part of Portland cement and not more than one and one-half (1-1/2) parts of sand or pebbles and may be finished as directed by the designer or owner.

(g) 

Thickness of Coats. The thickness of the first two (2) coats of such stucco plastering shall not be less at any point than three-quarters (3/4) inch, measuring from the outside of the lath.

(h) 

Weather Conditions. No such stucco work shall be done in freezing weather and, whenever such work is done in hot weather, it shall be sprayed occasionally with water so as to prevent it from checking or cracking.

(16) 

Patented Exterior Stucco. All patented exterior stucco hereafter used or applied shall be applied at least three-quarters (3/4) inch thick over the face of the lath, tile or other construction, said thickness to be exclusive of the stone or dash and thicker, if so specified by the manufacturers. If the factory specifications for the particular type of such stucco to be used call for one-coat work, the stucco shall be troweled on and brought to a level surface and to a thickness of not less than three-quarters (3/4) inch, outside of the lath or other construction to which it is applied, before the stone or dash is applied. If such factory specifications call for two (2) coat work, the first or scratch-coat shall be put on to a thickness of not less than three-eighths (3/8) inch over the face of the lath or other construction to which it is applied, and the finish or second coat shall be applied to a thickness of not less than three-eighths (3/8) inch before the stone or dash is thrown on.

No exterior stucco shall be applied on wood lath.

(17) 

Interior Basement Walls. Wherever the interior walls of basements are plastered below the grade of the lot, Portland cement mortar shall be used.

(18) 

Suspended Ceilings.

(a) 

Hangers. All hangers to be not less than three-sixteenths (3/16) round iron, anchored to top of floor construction with anchors not less than eight (8) inches long. If structural framing can be used, hangers shall be attached to the same. Hangers to be not less than No. 8 galvanized wire; three-fourths by three-sixteenths (3/4 x 3/16) inch flat or three-sixteenths (3/16) inch round mild steel spaced not to exceed four (4) feet in each direction.

(b) 

Carrying Bars. Carrying bars or runners shall not be less than one and one-half (1-1/2) inch channels of .422 pound not to exceed four (4) feet center to center. Channel furring shall be not less than three-quarter (3/4) inch channel of .276 pound twelve (12) inch center for three and four tenths (3.4) pounds flat lath, or twenty (20) inch center for three and five tenths (3.5) pound rib lath. The lath shall be fastened to the furring channels with at least eighteen (18) guage galvanized annealed wire spaced at least every six (6) inches. The furring channels shall be fastened to the carrier or runner channels by at least fourteen (14) gauge annealed wire, wrapped twice around both channels and secured by a double or triple twist to form the so-called "saddle tie."

(c) 

Weight of Lath. The minimum weight of lath shall be three (3) pounds per square yard.

(d) 

Carrying Ceiling. When the ceiling is to be plastered tight against the underside of joints, the following method of carrying the ceiling will be permitted: fourteen (14) gauge galvanized wire hangers placed not farther apart than twelve (12) inches along each joist and not less than eight (8) inches projecting below the beam or joist to fasten the channels to. The channels shall be not less than three-quarter (3/4) inch channels of .276 pound and shall run at right angles to the joists and not farther apart than twelve (12) inches. The lath shall then be fastened to the channels as specified above.

(19) 

Furring for Cornice. Furring of all false beams and cornice furring brackets to be made of standard (hot rolled) channel not less than three-quarter (3/4) inch or three-quarter by three-sixteenths (3/4 by 3/16) inch flat iron. These brackets where three-quarter (3/4) inch channel is used for cross furring for each member, shall not be placed more than three (3) feet apart. All work of this nature must be properly cross-braced so as to hold it to a true line for plastering. All brackets shall have hangers not to exceed three (3) feet on centers.

(20) 

Corner Beads. Corner beads shall be erected straight and true with clips or fastenings not over twenty-four (24) inches apart. Lathers are required to use either a line or straight edge and erect corner beads in a proper and workmanlike manner.

(21) 

Notice to Inspector. Every contractor, before doing any plastering work on any building, shall first notify the Building Inspector as to when the work of plastering to be commenced.