Publication Number 490-326, August 1996
"After a Disaster Roof Repairs 2: Basic Materials" dealt with basic materials. The single most important factor is that shingles of any length of bonding time, containing fiberglass or not, should meet the basic minimum standard "ASTM D 312-78." Number 15 felt is a material impregnated with asphalt so that it weighs at least 15 pounds per 100 feet and assists in moisture control in residences.
Directions here are for roofs with a slope of 4 inches or greater in 12 inches. Lesser slopes require different procedures:
First, apply the #15 building felt underlayment, fastening it down with 12-ga. roofing nails (with an annular thread when nailing into plywood) or staples one inch long driven through tin discs spaced a maximum of 12 inches on center. The single ply of underlayment is placed from peak to gutter with a 2-inch top lap, and a 4-inch end lap minimum.
Next, the shingles are applied. Usually instructions supplied by the manufacturer are the best to follow. Begin the starter course along the bottom edge of the roof and work to the top, following markings you have applied for squaring on the underlayment. Staying square and straight is a challenge. Fasteners need to be 12-ga., HD roofing nails (1.25 inches long) or 16-ga. 15/16 staples (1.25 inches long), spaced four per 36- to 40-inch section of shingle.
Overlapping instructions are supplied in printed instructions from the manufacturer, but the first line of shingles should overlap the roof edge 3/4" to allow for the final neat trim. A similar amount should overlap eaves. Overlaying sheathing edges allows sufficient material to protect edges of the sheathing from becoming wet. An additional and durable protection comes with flashing all edges of the sheathed deck before shingling. Flashing in roof valleys is also needed before finished roofing. Applying shingles to ridges and hips, as well as weaving valleys, requires some skilled help. This is not the place to try to skimp and pocket a little of the insurance money. Be wary of unskilled help in this process, or you may have to pay again soon to have the job redone, correctly.
Based on information developed by Clemson Cooperative Extension following Hurricane Hugo. Revised for Virginia audiences by Virginia Cooperative Extension.
For more information, contact your local office of Virginia Cooperative Extension.
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