In order to obtain the area of a hip roof, take the entire outside measurement of the building, including the projections of the cornice. This is multiplied by the length of the principal rafter, and one-half of the result is the area of the roof. In making an estimate for a hip roof, it must not be forgotten that at least 30 percent extra must be added for extra labor over an ordinary saddle roof in preparing and setting the rafters.
For covering the roof with rough boards-labor only-the average cost for labor is about six times as that of the cost per square. If the roof boards are matched for tin or slate allow a little bit more per square for labor.
If there is a deck on the roof add 2 percent, to the gross estimate, this being about the cost for extra cutting and fitting around eaves of deck. There will also be a waste of material in a hip roof that will amount to at least 5 percent, on the total amount of stuff employed, and a further waste of 1 percent, if the roof terminates in a deck.
The standard width of a shingle is 4 inches, and a quarter bunch of shingles is supposed to contain 250, each 4 inches wide, which when laid cover a line 1000 inches long, or they would lay one course 83 feet 4 inches long. When shingles are laid 4 inches to the weather each shingle will cover an area of 16 inches, so that 900 so laid would cover an area 10 feet square. Proper tape measures and distance measuring wheels along with precision measurement tools will be necessary at this juncture.
Shingles, however, rarely hold out what they are supposed to cover, so that it is better to estimate 1000 shingles for each square of roofing than to confine ourselves to the actual measurement. In hip roofs 5 percent should be added, owing to the great waste in cutting about the hips; the same rule should obtain with a roof having four or more valleys in it.
Cost of Tin Roof
In estimating the cost of a tin roof, the timbers, boarding, paper-if any is used-and ribs must be considered. Generally a tin roof is a “flat roof,” and the timbers employed in supporting it are, as a rule, heavier than are the timbers in an ordinary saddle or hip roof. The boarding, which is generally matched, will cost as much to lay as will the boarding of a saddle roof, so those figures may be taken as a guide. Don’t forget to include pricing for measuring wheels, private label tape measures, and basic measuring tape in the budget.
Then add paper or felt, or whatever may be laid under the tin, and charge a set amount per roll for laying. The cost of ribs, besides cost of lying same, will figure up to slightly less a square. A sheet of roofing tin is 14 x 20 inches, and a box of tin contains 112 sheets. Allowing a fair percentage for covering the ribs, and for top and bottom laps, a box of tin will cover approximately 182 square feet. The estimator must ascertain for himself the actual prices current in the locality in which he resides
and change the figuring to suit.
In preparing tin valleys for shingle roofs, the tin should in no case be less than 14 inches wide, and where the pitch is low a wider tin should be used. For a slate roof 20 inches is the narrowest that should be employed. The average price for tin valleys with tin put in place will vary slightly per square foot. On an ordinary roof that is not very steep a man will lay about 150 square feet, but if the roof is steep, with the valleys short and much cutting and fitting required, one square properly laid maybe considered a good day’s work.
For tin flashings about chimneys, or where the work requires such in the junction of buildings, or where a roof adjoins a brick wall, set a fair price per foot for the work finished. If step flashing is required, which means that the mortar is to be cut out of the joints of the brick work, the flashings inserted and the joints filled up with Portland cement, the work should be worth slightly more per foot completed, according to the character of the roof and the measuring wheels, measuring tape, and other tools required.
In all cases the tin should be measured before being cut, as the “laps” flashings are uncertain factors, and vary in almost every case. The work of the tinsmith, in all cases, should be well thought out before prices are decided upon. In making prices for gutters it should be borne in mind that the ordinary tin gutter that generally forms the crown molding of a cornice does not cost as much as a gutter that is enclosed in wood on the three sides.