In estimating on heating by furnace, the average cost of labor is about one-third that of materials. For steam and hot-water heating, the ratio is about one-fifth.
The cost of a hot-air installation is approximately 6 per cent. of the cost of the building; for steam heating, 8 per cent.; and for hot-water heating, 10 per cent.
PLUMBING AND GAS-FITTING
PLUMBING
96. An approximate figure for the cost of plumbing is 10 per cent. of the cost of the building. This figure is for good materials and labor, and of course is subject to considerable variation. The cost of labor alone will average about one-fourth the cost of the materials.
97. Drainage System.—In making estimates for the drainage system, measure all horizontal pipes from the plans and all vertical pipes from the sectional drawings.
Commence at the sewer outlet and measure the main-sewer line forwards into the building; then measure the horizontal branches.
Measure the vertical, soil, waste, and vent stacks to their terminations above the roof, and waste-pipe branches to the fixtures on the several floors.
Itemize the several pipes in the different kinds and classes.
Estimate all earthen pipe by the linear foot, allowing for Portland cement in the joints.