Rafters Sizes, High Slope (Over 3 in 12) With No Finished Ceiling - 20 psf Live Load, 7 psf Dead Load - 12 inch spacing
Calculating the size of the rafters you need when building a home or an addition is not a complex situation as we have provided a group of tables that will allow you to make your selection.
Note: Always check with your local building department to ensure that your choice of rafter sizes and material meets their requirements.
Four tables are provided:
- High Slope (Over 3 in 12) With No Finished Ceiling - 20 psf Live Load, 7 psf Dead Load - 12 inch spacing
- High Slope (Over 3 in 12) With No Finished Ceiling - 20 psf Live Load, 7 psf Dead Load - 16 inch spacing
- Low Slope (Over 3 in 12 or less) With No Finished Ceiling - 30 psf Live Load, - 12 inch spacing
- Low Slope (Over 3 in 12 or less) With No Finished Ceiling - 30 psf Live Load, - 16 inch spacing
| High Slope (Over 3 in 12) With No Finished Ceiling 20 psf Live Load, 7 psf Dead Load - 12" spacing |
|||||
Species |
Grade |
2 X 4 |
2 X 6 |
2 X 8 |
2 X 10 |
Coast Sitka Spruce |
Select structural |
11' 1" |
17' 4" |
22' 11" |
29' 2" |
No. 1 & Appearance |
11' 1" |
16' 5" |
21' 7" |
27' 7" |
|
No. 2 |
10' 3" |
15' 0" |
19' 10" |
25' 3" |
|
No. 3 |
7' 8" |
11' 4" |
15' 0" |
19' 1" |
|
Douglas Fir, Larch |
Select structural |
11' 3" |
17' 8" |
23' 4" |
29' 9" |
No. 2 |
11' 1" |
17' 4" |
22' 11" |
29' 2" |
|
No. 3 |
8' 11" |
13' 6" |
17' 10" |
22' 9" |
|
Eastern Hemlock- |
Select structural |
10' 1" |
15' 11" |
20' 11" |
26' 9" |
No. 2 |
9' 7" |
15' 0" |
19' 10" |
25' 3" |
|
No. 3 |
8' 4" |
12' 5" |
16' 5" |
20' 11" |
|
Hem-Fir (North) |
Select structural |
10' 7" |
16' 8" |
22' 0" |
28' 0" |
No. 2 |
10' 4" |
15' 8" |
20' 8" |
26' 5" |
|
No. 3 |
7' 11" |
12' 1" |
15' 11" |
20' 4" |
|
Ponderosa Pine |
Select structural |
9' 10" |
15' 6" |
20' 5" |
26' 0" |
No. 2 |
9' 7" |
14' 6" |
19' 1" |
24' 4" |
|
No. 3 |
7' 5" |
11' 1" |
14' 8" |
18' 8" |
|
Red Pine |
Select structural |
10' 1" |
15' 11" |
20' 11" |
26' 9" |
No. 1 & Appearance |
10' 1" |
15' 8" |
20' 8" |
26' 5" |
|
No. 2 |
9' 10" |
14' 3" |
18' 10" |
24' 0" |
|
No. 3 |
7' 5" |
10' 10" |
14' 4" |
18' 3" |
|
Spruce Pine Fir |
Select structural |
10' 7" |
16' 8" |
22' 0" |
28' 0" |
No. 1 & Appearance |
10' 7" |
16' 1" |
21' 2" |
27' 0" |
|
No. 2 |
10' 0" |
14' 8" |
19' 4" |
24' 8" |
|
No. 3 |
7' 6" |
11' 1" |
14' 8" |
18' 8" |
|
Western Cedars |
Select structural |
9' 7" |
15' 0" |
19' 10" |
25' 3" |
No. 2 |
9' 3" |
14' 7" |
19' 2" |
24' 6" |
|
No. 3 |
7' 6" |
11' 4" |
15' 0" |
19' 1" |
|
Western White Pine |
Select structural |
10' 4" |
16' 3" |
21' 6" |
27' 5" |
No. 1 & Appearance |
10' 4" |
15' 8" |
20' 8" |
26' 5" |
|
No. 2 |
9' 7" |
14' 1" |
18' 7" |
23' 8" |
|
No. 3 |
7' 3" |
10' 10" |
14' 4" |
18' 3" |
|