After the lining of the first floor is laid, the basement floor is to be put in. On the base of concrete 3 inches thick, composed as for footings, before it has set, put a wearing-surface 1/2 inch thick, composed of 1 part cement to 3 parts crushed granite, troweled to a smooth, level surface.

Reinforced concrete beams and slab over sidewalk coal-cellar, are to be composed of 1 part Portland cement, 3 parts sand, and 5 parts gravel or broken stone which will pass through a 3/4-inch ring. This is to be tamped in the forms and around the reinforcing metal, to form a solid, compact mass, As the strength of this slab is dependent principally on the care in mixing the material and in placing it, it must be tested three weeks after it is set, by placing five layers of brick over the entire surface. If under this test it fails or cracks, it is to be removed and replaced at the Contractor's expense.

After the completion of the building, a sidewalk in all respects matching that now in place is to be continued over the concrete slab, and the iron coal-hole cover-frame is to be built in so as to set flush with the surface.