Sec. :39. Lining Existing Walls. In ease it is desired to increase the height of existing party or independent walls which are less in thickness than required under this Code, the same shall he done by a lining of brickwork to form a combined thickness with the old wall of not less than 4 inches more than the thickness required for a new wall lug with the total height of the wall when so increased in height, The said linings shall be supported on proper foundations and carried up to such height as the Commissioner of Buildings having jurisdiction may require. No lining shall be less than 8 inches in thickness; and all lining shall be laid up in cement mortar, and thoroughly anchored to the old brick walls with suitable wrought-iron anchors, placed 2 feet apart and properly fastened or driven into the old walls in roses alternating vertically and horizontally with each other, the old walls being first cleaned of plaster or other coatings where any lining is to be built against the same. No rubble wall shall be lined except after inspection and approval by the Department.
Sec. 91. Walls Tied, Anchored, and Braced. In no case shall any wall or walls of any building be carried up more than two stories in advance of any other wall, except by permission of the Commissioner of Buildings having jurisdiction; but this prohibition shall not include the inelosure walls for skeleton buildings. The front, rear, side, and party walls shall lie properly bonded together, or anchored to each other every 6 feet in their height by wrought-iron tie anchors, not less than inches by % inch in size, and not less than 24 inches in length. The side anchors shall be built into the side or party walls not less than 16 inches, and into the front and rear walls, so as to secure the front and rear walls to the side or party walls when not built and bonded together. All exterior piers shall be anchored to the beams or girders on the level of each tier. The walls and beams of every building, during the erection or alteration thereof, shall be strongly braced from the beams of each story, and, when required, shall also he braced from the outside, until the building is inclosed. The roof her of wood beams shall he safely anchored, with plank or joist, to the beams of the story below, until the building is inclosed.
Sec. 42. Arches and Lintels. Openings for doors and windows in all buildings shall have good and sufficient arches of stone, brick, or terra-cotta, well built and keyed with good and sufficient abutments or lintels of stone. iron, or steel of sufficient strength, which shall have a bearing, at each end, of not less than 5 inches on the wall. On the inside of all openings in which lintels shall be less than the thickness of the wall to be supported, there shall be timber lintels, which shall rest at each end not more than 3 inches on any wall, which shall be chamfered at each end, and shall have a suitable arch turned over the timber lintel. Or the inside lintel may
be of east iron or wrought iron or steel; and in such case stone blocks or cast-iron plates shall not be requires] at the ends where the lintel rests on the walls, provided the opening is not more than 6 feet in width.
All masonry arches shall be capable of sustaining the weight and pressure which they are designed to carry; and the stress at any point shall not-exceed the working stress for the material used, as given in section 139 of this Code. Tie-rods shall be used where necessary to secure stability.
Sec. 43. Parapet Walls. All exterior and division or party walls over 15 feet high, excepting where such walls are to be finished with cornices, gutters, or crown mouldings, shall have parapet walls not less than 8 inches in thickness, and carried 2 feet above the roof ; but for warehouses, factories, stores, and other buildings used for commercial or manufacturing purposes; the parapet walls shall be not less than 12 inches in thickness, and carried 3 feet above the roof, and all such walls shall be coped with stone, terra-cotta, or cast iron.
Sec. 44. Hollow Walls. In all walk that are built hollow, the same quantity of stone, brick, or concrete shall be used in their construction as if they were built solid, as in this Code provided; and no hollow wall shall be built unless the parts of same are connected by proper ties, either of brick, stone, or iron, placed not over 24 inches apart.
Sec. 45. Hollow Bricks on Inside of Walls. The inside 4 inches of all walls may be built of hard-burnt hollow brick, properly tied and bonded into tile walls, and of the dimension of ordinary bricks. Where hollow tile or por ons terra-cotta blocks are used as lining or furring for walls, they shall not be included in the measurement of the thickness of such walls.
Sec. 46. Recesses and Chases in Walls, Recesses for stairways or elevators may be left in the foundation (or cellar) walls of all buildings, but in no case shall the walls be of less thickness than the walls of the fourth story, unless reinforced by additional piers with iron or steel girders, or iron or steel columns and girders, securely anchored to walls on each side. Recesses for alcoves and similar purposes shall have not less than 8 inches of brickwork at the back of such recesses; and such recesses shall he not more than 8 feet in width, and shall be arched over or spanned with iron or steel lintels, and not carried up higher than 18 inches below the bottom of the beams of the floor next above.