Lumber Roof Size

This tells you the size of the beam needed to support the porch s roof.

Lumber roof size.

The term dimensional lumber came into popular use around the beginning of the 20th century to distinguish lumber cut to pre determined sizes from other types of wood such as corded wood for fireplaces during this period the building industry sought to control costs and minimize waste by developing standard sizes and grades for building timber. 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. For a porch roof the beam needs to be. The dead load is constant and is estimated as 10 pounds per square foot for wood framed construction.

Dimensional lumber and modern building. Before lumber companies began selling osb the standard choice for sheathing a roof with a 24 inch rafter spacing was 1 2 inch cdx plywood the letters cdx indicate that it is construction grade. 1 ft 0 3048 m. Most interior beams need to include the roof load.

If there is are any questions about anything else then you should contact your supplier or an engineer. 2 are indicated below. Last updated july 15 2018. Weather you re building a shed roof or adding a dormer to your second story it is important to choose the proper size rafter.

Douglas fir maximum horizontal roof rafter span for lumber grade selected structural and no. 1 psf lb f ft 2 47 88 n m 2. This means the example porch would need a 6 inch by 8 inch beam. The following tables give details of the allowable spans and spacing for some of the more common timber sizes used in traditional roofing construction.

There are several variables to consider when determining the proper rafter size. This sizing guide for roof rafters will help determine what you need for your small project. Dead load weight of structure and fixed loads 15 lbs ft 2. Live load is weight of furniture wind snow and more.

This calculator matches up with 90 of the applications in the 2012 international residential code book. Pitched roof timber sizes. In the example d calculates to 7 75.