Lumber Roof Loads

The load on an outside wall with clear span trusses is exactly half the load on each wall.

Lumber roof loads.

If you place the 2x6s at 16 o c then syp can span over 16 and spf can span 14. Live load psf dead load psf span calculator for wood joists and rafters available for the iphone. Determine the load per square foot that the roof must support. You can t beat sawn lumber for most small window headers but as spans and loads increase stronger materials are a better choice.

An spf roof at the same spacing and lumber size will span 11. The loads are based on adjusted roof snow loads from the governing building code. A complete analysis of wood s mechanical properties is complex but understanding a few basics of lumber strength will allow you to size joists and rafters with the use of span tables. For roof live loads of 12 psf or 16 psf.

Sawn lumber limits design potential and in some cases just doesn t work. Let s start by taking a broad view. Too often builders gang together 2 inch dimension lumber to support roof and floor loads without considering other options. Span calculator for wood joists and rafters also available for the android os.

For example if building is 24 x 24 and has trusses and the load on the roof will be for 30 lb snow load and a ceiling with no storage will total out like this. The live load depends on the maximum snow load in your area. These numbers are for roofs supporting light loads of 20 pounds for square foot. The structural goal of a house is to safely transfer building loads weights through the foundation to the supporting soil.

Roof rafter span use this table to determine the maximum lengths of roof rafters based on species and grade of lumber spacing dimensions load and slope. A clay tiled roof may have a dead. The load increases with the use of heavier roofing material. The dead load of a typical asphalt shingled wood framed roof is about 15 pounds per square foot.

Use this table to determine the maximum lengths of floor joists based on species of lumber joist spacing and joist size. Wood screws withdrawal forces allowable withdrawal load force wood species moisture content and weight weight of green and air dried fire wood wood panel and structural timber products mechanical properties density fibre stress compressive strength and modulus of elasticity of clear wood panel and structural timber products. For heavy loads at 24 o c 2 6 syp can span up to 9. For roof live loads less than 20 pounds per square foot psf rafter spans and required e values tabulated for 20 psf shall be permitted to be adjusted in accordance with the fol lowing table.