Roof Rafter Deflection Limit

2 are indicated below.

Roof rafter deflection limit.

2x4 2x6 2x8 2x10 2x12. 1 psf lbf ft2 47 88 n m2. Maximum deflection limits are set by building codes. This is the easiest way to determine allowable dead loads live loads and deflection limits.

For sandwich panels used in roofs or walls of sunroom additions or patio covers the total load deflection shall not exceed l 120. The code section on working load deflection states. They are expressed as a fraction. Roof beam double span.

Clear span in inches l over a given number. You can also use af pa s span tables for joists and rafters. On a roof with a slope greater than 4 to 12 the live load limit is typically adjusted downward from 20 psf to 15 psf to allow for the relatively greater dead load on the steeper roof. L 240 for unplastered floor construction.

Douglas fir maximum horizontal roof rafter span for lumber grade selected structural and no. And l 180 for unplastered roof construction. For continuous aluminum structural members supporting edge of glass the total load deflection shall not exceed l 175 for each glass lite or l 60 for the entire length of the member whichever is more stringent. L 720 l 600 l 480 l 360 l 240 l 180.

Spacing in 12 16 19 2 24. 3 stud construction standard utility. Default deflection criteria for the following members. The deflection of floor and roof assemblies shall not be greater than l 360 for plastered construction.

Ridge beam double span. Roof beam single span. For example the allowable deflection of a 12ft span floor joist with plaster l 360 is 0 4 12ft divided by 360. See the table below.

A floor joist appropriately selected to span 10 feet with an l 360 limit will deflect no more than 120 360 1 3 inches under maximum design loads. Ridge beam single span. Floor joists ceiling joists rafters snow load rafters roof live load deflection limit. Live load is weight of furniture wind snow and more.

This publication has a much more extensive. Note it gives the allowable deflection based on a fractional span quantity so a larger denominator will yield less deflection. Supporting roof and floor. The l is the length in inches of the clear span of the joists or rafters that make up the ceiling.

So these are the limits set by the code.