Maximum Horizontal Roof Rafter Span

Douglas Fir and maximum span

Douglas fir maximum horizontal  roof rafter span for Lumber Grade Selected Structural and No. 1 and No. 2, are indicated below. Max. dead load (weight of structure and fixed loads) 15 lbs/ft2. Live load is weight of furniture, wind, snow ..

  • 1 psf (lbf/ft2) = 47.88 N/m2

Max. Live Load 20 lbs/ft2

Maximum Span (ft - in)
Nominal Size
(inches)
Rafter Spacing, Center to Center
(inches)
Lumber Grade
Selected Structural No. 1 No. 2
2 x 6 12 16' - 4'' 15' - 9'' 14' - 9''
16 14' - 11'' 13' - 8'' 12' - 9''
24 13' 11' - 2'' 10' - 5''
2 x 8 12 21' - 7'' 19' - 11'' 18' - 8''
16 19' - 7'' 17' - 3'' 16' - 2''
24 17' 14' - 1'' 13' - 2''
2 x 10 12 27' - 6'' 24' - 4'' 22' - 9''
16 25' 21' - 1'' 19' - 9''
24 20' - 9'' 17' - 3'' 16' - 1''
2 x 12 12 33' - 6'' 28' - 3'' 26' - 5''
16 29' - 5'' 24' - 5'' 22' - 10''
24 24' 20' 18' - 8''

Max. Live Load 60 lbs/ft2

Maximum Span (ft - in)
Nominal Size
(inches)
Joist Spacing Center to Center
(inches)
Lumber Grade
Selected Structural No. 1 No. 2
2 x 8 12 15' - 0'' 13' - 7'' 12' - 3''
16 13' - 7'' 11' - 9'' 11'
24 11' - 7'' 9' - 8'' 9'
2 x 10 12 19' - 1'' 16' - 8'' 15' - 7''
16 17' - 4'' 14' - 05'' 13' - 6''
24 14' - 2'' 11' - 9'' 11'
2 x 12 12 23' - 3'' 19' - 3'' 18'
16 20' - 1'' 16' - 8'' 15' - 7''
24 16' - 5'' 13' - 8'' 12' - 9''
2 x 14 12 25' - 11'' 21' - 7'' 20' - 2''
16 22' - 6'' 18' - 8'' 17' - 5''
24 18' - 4'' 15' - 3'' 14' - 3''

Related Topics

  • Beams and Columns - Deflection and stress, moment of inertia, section modulus and technical information of beams and columns

Related Documents

  • Live Loads - Minimum uniformly distributed live loads

Tag Search

  • en: horizontal roof rafter span live load dead load lumber size stuctural
  • es: horizontal techo lapso viga de carga viva de madera de carga muerta tamaño stuctural
  • de: horizontale Dachsparren Spanne Last Eigenlast Holz Größe Stuctural

Search the Engineering ToolBox

- "Search is the most efficient way to navigate the Engineering ToolBox!"

Engineering ToolBox - SketchUp Extension - Online 3D modeling!

3D Engineering ToolBox Extension to SketchUp - add parametric components to your SketchUp model

Add standard and customized parametric components - like flange beams, lumbers, piping, stairs and more - to your SketchUp model with the Engineering ToolBox - SketchUp Extension/Plugin - enabled for use with the amazing, fun and free SketchUp Make and SketchUp Pro. Add the Engineering ToolBox extension to your SketchUp from the Sketchup Extension Warehouse!

Translate the Engineering ToolBox!
About the Engineering ToolBox!

close