Wood beam spans 2

[reverbz]

Hey guys,

For 2x's and other sizes of typical lumber, what do you typically try to limit your spans to? Mostly asking about solid sawn here though don't mind hearing about GLB and other specialty products if you know it off the top of your head.

Thank you!

 

[JStructsteel]

Usually L/360 deflection for floors. For rafters L/240.

 

[XR250]

Depends on the "quality" of the house. For most that I do...
2x8 - 10 ft.
2x10 - 12 ft.
2x12 - 14 ft.
Also, depends on the room. For Kitchens or baths I may go less due to the weight of expensive materials.

Calcs out well above L/360.
I don't use L/360 for any floor unless my feet are held to the fire.

 

[nicculusreadicculus]

It depends on where the beam is going, i.e. roof, attic, floor? that determines what loads and deflection limit I will use. usually 20 DL/20 Lr for roof, 10DL/20LL for ceiling/attic, and 15DL/40LL for floor. I started going to L/480 for floor deflection. IRC Span Charts are wonderful for quickly finding a size

 

[phamENG]

If running calcs, L/480 (max 1/2") for live load deflection of joists, L/600 (max 3/4") for girders. Unless, of course, strength controls. But that's actually pretty rare for high end homes. If pulling from IRC tables, always go up one size.

IRC tables are okay for older style homes with lots of split up rooms. Larger rooms and open areas, even if it 'works' based on IRC tables, the floors are often quite bouncy.

 

[RontheRedneck]

I like to limit floor members to a span/depth ratio of 18 to 1. (18 foot max span for a 1' deep floor member)

For beams I like to start with 12 to 1 and go from there.