The Roof Is The Equivalent To 0 5 In Of Wood

A comprehensive source of technical information on wood characteristics is the wood engineering handbook second edition forest products laboratory 1990.

The roof is the equivalent to 0 5 in of wood.

4 prescriptive rafter span tables. A common choice for flat roofing material is epdm rubber as it is highly durable waterproof and can be made from recycled materials. Make sure the shear value fv for the species and grade you use exceeds the fv listed in the span table. Floor assemblies using wood trusses may be approved for exemption if the floor assembly demonstrates equivalent fire performance.

Osb and plywood come in thicknesses ranging from 5 16 to 3 4 inch and the thickness needed for a particular roof depends on several factors including rafter spacing expected load and roof design. 2015 irc section r502 8 1. When the header joist span does not exceed feet the header joist may be a single member the same size as the floor joist. Most metal roof covering comes with a 30 to 50 year warranty with most types lasting far longer.

The dead load of a typical asphalt shingled wood framed roof is about 15 pounds per square foot. A clay tiled roof may have a dead. Therefore in order to apply this exemption to floor trusses the trusses must be tested and evaluated for equivalency to the fire performance of nominal 2 x 10 lumber. Continuous insulation 0 0 5 osb 7 16 0 62 0 62 0 62 spf stud 6 875 6 875 6 875 spf header 6 875 6 875 6 875 cavity insulation 20 25 20 1 2 drywall 0 45 0 45 0 45.

The smallest pitch of a roof is 0 5 12. If you size a roof beam like a structural ridge that has a l 240 limitation you would multiply the minimum e value by 0 666 785 000 x 0 666 522 810 in this case. The load increases with the use of heavier roofing material. A completely flat roof is a poor design as water and snow will collect on it eventually leading to your roof collapsing in from the weight of it all.

It is a lightweight choice very long lasting and very resistant to. Again equivalent alternatives are possible through the u factor approach. For l 180 multiply by 0 5. The tension side of floor joist members inches or greater in nominal thickness shall not be notched except at the ends of the members.

Pvc or vinyl flat roofing is one of the most common forms of flat roof coverings. Chapter 5 design of wood framing 5 2 1 lumber general as with all materials the designer must consider wood s strengths and weaknesses.