According to the National Roofing Contractors Association, shingle installation should be done in accordance with local building code. However, other factors, such as area weather and type of shingle also play a part in how shingles are installed.

Asphalt shingles for New York roofs are most commonly available in strips of 36 inches long by 12 inches wide. Each strip has a set of three “tabs,” which provide the visual “shingle” effect when installed correctly. Each 3-tab strip has a layer of adhesive just above the tabs. The heat of the sun activates the adhesive, which binds to the layer below and creates a seal that augments the nails when installed.

A starter course (layer) of shingle strips with the exposed tab portion cut off is installed on the eave edges of the roof. The starter course’s vertical and horizontal edges should extend between 1/4 inch to 3/4 inch beyond the edges of the rake and eave. The starter course should be secured with roofing nails applied 2-1/2 inches to 4 inches above the edge of the eave, and between 6 inches to 9 inches apart over the entire length.

After the starter course, the shingles are installed in an offset pattern of a consistent measurement, usually 4 or 5 inches. This ensures complete coverage and gives the finished roof an attractive visual pattern. The pattern is begun in this manner:

1. Starting on the left side of the roof at the eave, place the first full shingle strip directly over the starter course at the eave and rake edges. Each complete strip should be secured by a minimum of four roofing nails, spaced evenly (high wind areas may require six nails per strip).

2. Cut 4 inches from the left side of the next tab strip, and install directly in line with the left edge of the previous strip.

3. The next strip should be cut to 8 inches and installed in the same manner.

4. Continue shortening each strip by an additional 4 inches for every subsequent row until the last row is a 4-inch tab.

5. Continue the pattern to the right of the first set, using whole 3-tab strips.

Always consult a Boston roofing contractor to install any type of shingles. Make sure to check Angie's List and references before hiring.