Estimating Building Costs (Paperback)

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1917 Excerpt: ... ft. The square root total is 1,139. Fig. 8 shows the three pitches. Coming to Fig. 7 we see the advantage of this method of taking off areas. It is not really required on such a roof as shown in Fig. 6. In this plan the building line is shown solid, and the projections are dotted. The dotted projection at the dormer shows why all such duplications have to be added extra. The main roof directly below the dormer projections is necessarily included in the first total, and when a roof above a roof is built it has to be added extra. Fig. 10 shows this at A and B. The slopes at B are taken in by the first main estimate, for 42 per cent.--in the case of a pitch roof--is added for all the area, and therefore the dormer projections at Fig. 10 must be included in addition. Fig. 7 shows the same plan, 26 x 30 inside the wall line, and 30 x 34 over the cornice. There is also an L, 8x12 wall line, and 8x16 over the cornice. Fig. 9 shows the elevation without the cornice. A contractor taking off the area for a pitch, as shown here, and following the foregoing method, would simply multiply 30x34=1,020, and add 8x 16=128, making a total of 1,148, plus 42 per cent. for the rise, 482 sq. ft., equals in all, 1,630 sq. ft. Adding 36 ft. for a narrow cornice at the dormer the roof area for this pitch is 1,666. Change of Pitch.--But some roofs have a regular pitch almost down to the wall plate, and then change to a flatter one, and for this reason it is sometimes better to estimate the area strictly to the wall line and add the projections of the main and dormer cornices separately. This is especially the case with wide cornices, if they are not regular in pitch. TABLE FORTY-THREE Board Measure to Square of Roof for 2 x 4 Rafters 12" centers 81 ft. 20" centers 51 ft. ...