Span Of The Roof

Longevity depends on the climate of an area the way the original installation was handled and whether ongoing care and maintenance have been part of a regular routine.

Span of the roof. The spans in this table are based on a maximum supported rafter span of 16 feet where the supported span is the total horizontal distance spanned by the roof rafters divided in half not the diagonal distance or the length of the rafter. Rafter span tables use these tables to determine lengths sizes and spacing of rafters based on a variety of factors such as species load grade spacing and pitch. The average lifespan of your roof depends on the type of roofing material you have installed. Span roof definition a roof having two slopes of equal breadth and pitch meeting at a common ridge.

Shingle roofs tend to have a shorter lifespan than other options such as tile. The average lifespan of a shingle roof is based on a number of factors. The average lifespan of asphalt shingles ranges from 20 to 40 years depending on the manufacturer although many warranties only guarantee between 15 and 25 years. So this table could accommodate a house with a total rafter span or house width of 32 feet.

Visit the roof framing page for more information on cutting roof rafters and visit the roof pitch calculator for determining rafter lengths based on rise and run.