Floor Joist Sizes & Spans – 16 inch spacing – 30 psf
Calculating the size of the floor joists you need when building a home or an addition is not a complex situation as we have provided a chart that will allow you to make your selection.
Note: Always check with your local building department to ensure that your choice of floor joist size and material meets their requirements.
Four charts are provided:
- 40 psf and 12 inch spacing
- 40 psf and 16 inch spacing
- 30 psf and 12 inch spacing
- 30 psf and 16 inch spacing
| 16 Inch Spacing - 30 psf - Floor Joist | |||||
Species |
Grade |
2 X 6 |
2 X 8 |
2 X 10 |
2 X 12 |
Coast Sitka Spruce |
Select structural |
10' 11" |
14' 5" |
18' 5" |
22' 5" |
No. 1 |
10' 10" |
14' 4" |
18' 3" |
22' 3" |
|
No. 2 |
10' 0" |
13' 2" |
16' 9" |
20' 5" |
|
No. 3 |
7' 6" |
9' 11" |
12' 8" |
15' 5" |
|
Douglas Fir, Larch |
Select structural |
11' 2" |
14' 8" |
18' 9" |
22' 10" |
No. 2 |
10' 11" |
14' 5" |
18' 5" |
22' 5" |
|
No. 3 |
9' 0" |
11' 10" |
15' 1" |
18' 4" |
|
Eastern Hemlock- |
Select structural |
10' 0" |
13' 2" |
16' 10" |
20' 6" |
No. 2 |
9' 6" |
12' 6" |
15' 11" |
19' 4" |
|
No. 3 |
8' 3" |
10' 11" |
13' 11" |
16' 11" |
|
Hem-Fir (North) |
Select structural |
10' 6" |
13' 10" |
17' 8" |
21' 6" |
No. 2 |
10' 3" |
13' 6" |
17' 3" |
21' 0" |
|
No. 3 |
8' 0" |
10' 6" |
13' 5" |
16' 4" |
|
Ponderosa Pine |
Select structural |
9' 9" |
12' 10" |
16' 5" |
19' 11" |
No. 2 |
9' 6" |
12' 6" |
15' 11" |
19' 4" |
|
No. 3 |
7' 4" |
9' 9" |
12' 5" |
15' 1" |
|
Red Pine |
Select structural |
10' 0" |
13' 2" |
16' 10" |
20' 6" |
No. 2 |
9' 6" |
12' 6" |
15' 11" |
19' 5" |
|
No. 3 |
7' 3" |
9' 6" |
12' 2" |
14' 9" |
|
Spruce Pine Fir |
Select structural |
10' 6" |
13' 10" |
17' 8" |
21' 6" |
No. 2 |
9' 9" |
12' 10" |
16' 4" |
19' 11" |
|
No. 3 |
7' 4" |
9' 9" |
12' 5" |
15' 1" |
|
Western Cedars |
Select structural |
9' 6" |
12' 6" |
15' 11" |
19' 4" |
No. 2 |
9' 2" |
12' 1" |
15' 5" |
18' 9" |
|
No. 3 |
7' 6" |
9' 11" |
12' 8" |
15' 5" |
|
Western White Pine |
Select structural |
10' 3" |
13' 6" |
17' 3" |
21' 0" |
No. 2 |
9' 4" |
12' 4" |
15' 8" |
19' 2" |
|
No. 3 |
7' 3" |
9' 6" |
12' 2" |
14' 9" |
|