Roofing shingles should be thick at the butt. The most popular thickness is expressed as 5/2, meaning that the butts of five shingles will measure 2″ in thickness, so that each shingle is 2/5″ thick, at the butt, tapered, of course, to less than an eighth of an inch at the tip.
These shingles should be put on with galvanized nails, as the blued or bright nails will soon rust and let the shingles blow off.
Expose wood shingles about 41/2″ to the weather on the flatter roofs, and 5″ to the weather on the steeper roofs. Note that the roof must not be too flat for shingle roofs, minimum rise 5″ per foot of run.
Shingles are laid with a small space, about 1/4” wide, between the shingles. If they are laid too tightly together, they will buckle when they get wet, look unsightly, and give opportunity for the rain to blow under them.
Always put two nails in every shingle, no matter how wide or narrow. Split all shingles over 8″ in width, as they will split of themselves if you don’t do it.
To start shingles, stretch a line along the lower edge of the roof about two inches out from the cornice. To do this put a shingle on at each end of the roof, and let it project the required two inches beyond the cornice. Then with shingle nails in the ends of these shingles, tie the string and stretch it tightly.
This will give you the line for the first course of shingles. Always double the first course of shingles; that is, lay a second course directly on top of the first course, with the lower ends even so that you have two thicknesses of shingles at the start.
Then measure up 41/2” or whatever your exposure is to be and strike a chalk line, or lay a straight piece of 1″ x 6″ on the correct line to mark the bottom of the next course. Put the next course of shingles to this line, or against the straight edge, and nail them in place. Put the nails about 3/4” from the edges of the shingle, and far enough up so the next course will cover them. Give the shingles a side lap of at least 11/2″.
Sheathing does not need to be tight together for shingles. Do not use roofing paper under wood shingles.
For asphalt or composition roofing shingles the sheathing must be tight together. If you want a projection at the eaves, it will be necessary to support the asphalt shingles, as they are too limber to project by themselves. An easy way to accomplish this is to use a double course of wood shingles at the eaves, giving a projection of about 11/2″; the asphalt shingles can then be made even with the wood shingles and will be adequately supported. This will get the drip far enough away from the cornice.
To get a smooth effect, some shinglers place the first course of asphalt shingles with what is normally the top edge toward the bottom, then place the next shingle immediately on top of this one in the regular way to start the pattern of the shingling.
Care should be taken to keep the pattern of the roof running in straight lines, as the regular size of the composition shingles make any deviation very noticeable. If you get started right, no difficulty should be encountered.
Nail the composition shingles with 7/8” galvanized roofing nails, or with other size if recommended by the manufacturer. Directions for placing composition shingles usually come in the bundle with the shingles.
It is a good precaution to put a layer of 30 1b. felt on the sheathing before placing asphalt shingles.
The principal disadvantage of wood roofing shingles or asphalt and paper shingles is that they are not fireproof.
The fireproof roofing materials include such materials as slate, tile, rigid asbestos shingles, copper, and galvanized iron.
With some careful self-application you should be able to construct a sound roof.