383. - The following specifications are intended to include the fireproofing of all the steel in the building, the filling in between the beams forming floors and roof, and the concreting over the same to the top of the floor strips. Also the covering of all columns, both those standing clear and those partly incased in the walls. Also the building of all tile partitions and tile vaults, and the walls of pent houses on the roof.

* If in the general conditions this paragraph may be omitted. † Baker's Treatise on Masonry Construction.

‡ Modeled after the specification for the Fort Dearborn Building, Chicago; Messrs. Jenney & Mundie, architects.

This contractor shall furnish all material, including the mortar for setting the same, and shall do all his own hoisting and set all the work in a thorough, substantial and workmanlike manner, to the satisfaction of the superintendent.

Mortar. - All work shall be laid in mortar composed of 3 parts of best fresh lime mortar and 1 part best (Louisville) cement, thoroughly mixed together just before using. Said lime mortar shall be composed of fresh-burned lime and clean, sharp sand in proportions best suited to this work. (For partitions Acme cement plaster may be used. See Section 344.)

Floors. - All floors shall be constructed of flat arches (of porous or semi-porous tile, end-method construction*) set in between the beams and of a shape that will give a uniform flat ceiling in the rooms below. The bottoms and projections of all beams and girders must be protected by projecting parts of tile or by separate beam slabs. In laying the floor arches every floor joint shall be filled full over its entire surface from top to bottom. No joints to exceed 3/16 inch in thickness.

No clipped or broken tiles will be allowed in the arches, and no cutting of arches will be permitted except where absolutely necessary and under the approval of the superintendent. All the arches must be formed to fit the various spans between floor beams, and in all cases special patterns of voussoirs or keys must be moulded and set where it is impossible to set the regular form.

All floor arches, ten days after they are laid, and before they are concreted, shall be subject to a test of a roller, 15 inches face, and loaded so as to weigh 1,500 pounds, rolled over them in any direction.

[This test is only intended to provide against poor workmanship and improper setting of the tile. If any system whose strength has not been fully demonstrated is to be used, it should be subjected to a more severe test. See Section 299.]

Columns. - All columns shall be covered with (porous) column tile held by metal clamps, both in horizontal and vertical joints. These column protections shall be so made as to conform with the city ordinance.

[Where the city ordinance is not sufficiently strict on this point, the specifications should be more definite as to the shape of the tile. See Section 318.]

Roof. - The roof shall be constructed in the same way as the floors, except that the top of the tile shall be flush with the beams and the soffits may be segmental, with raised skewbacks.

Partitions. - Build all partitions shown on the several plans of (porous, semi-porous or dense) hollow tile, 4 inches thick in the first and second stories and 3 inches thick in all other stories except the hall partitions, which are to be 4 inches thick throughout the building.

In glazed partitions the lower parts and all parts other than the sash and frames shall be of tile.

* This clause is not in the Fort Dearborn specification.

The tiles shall be set breaking joints and to be tied with metal ties or clamps.

Furring for False Beams and Cornices. - This contractor is also to furnish and put in place tile furring for the cornice and false beams in the (bank and assembly hall), to be of profiles and sections as shown by drawings. (See Section 349.)

The cove and ceiling pieces of the cornice, and all parts of the beams, to have holes cast for bolts, spaced not over 12 inches apart and at least two bolts for each piece. The furring to be properly and securely mitred at angles and all to be properly bedded, with close joints, in mortar as specified above.

All suspended pieces to be substantially fastened in place by -inch diameter T-head bolts, spaced not over 12 inches apart, with nuts and washers to each.

(Or, all furring for cornices and false beams will be put up by the contractor for plastering.)

Wall Furring. - Fur the outside walls in finished portions of basement with 3-inch (porous, semi-porous or dense) tile so as to form a vertical and true surface for tiling. The tiles to be set with the hollow spaces vertical, and to be securely fastened to the wall by flat-headed spikes.

Miscellaneous. - All tile work shall be straight and true.

All tiles of every kind must be thoroughly burned and free from serious cracks or checks, or other damages, and shall be laid in a proper and workmanlike manner.

No centres to be lowered until the mortar has set hard.

All structural steel on which the strength of the building depends in any way, including wind bracing, shall be protected by fireproof covering of approved shape and substantially fixed in place.

All tilework to be left in suitable condition for plastering.

Concreting. - This contractor shall fill in on top of the floor arches with concrete composed of 1 part (natural) cement mortar and 4 parts of screened boiler cinders, to be leveled off at the top of the highest beams or girders, and after the floor strips are set by the carpenter to be filled in between said strips with the same concrete pressed down hard with a reasonably true surface 1/8 inch below the top of the strips.

All damage to tile work to be repaired before the concrete is laid.

Roof. - This contractor shall cover the surface of the roof tiles with 1 to 3 (natural) cement mortar of sufficient thickness to come inch above the top flanges of beams and girders, and to give the desired pitch to the roof, with a reasonably uniform surface.

[If the tops of the tiles are more than \ inch below the tops of the girders, concrete may be used for filling to top of girders and inch of mortar applied above.]

Outside Walls. - The outside walls of pent house on roof to be built of (4-inch) hard-burnt wall tile, clamped together, and set in mortar as above specified. Every joint, both vertical and horizontal, to be thoroughly filled over its entire surface with mortar, and all outside joints to be struck in a neat and workmanlike manner.

This contractor shall give a written guarantee that the outside face of these tile will stand the weather for (five) years dating from the completion of the wall, and agree to replace any tile injured by the weather, either in winter or summer during said period, promptly and at his own expense.