The table below shows the distance a beam extends from one post to the next.
For non stress-graded redwood lumber, with a live load of 40 lbs. per sq. ft. and a dead load of 10 lbs. per sq. ft.
| Beam Sizes | |||
| Beam spacing | 4x6 |
4x8 |
4x10 |
| 6 feet | 4'0" |
5'0" |
7'3" |
| 8 feet | 3'3" |
4'3" |
6'3" |
| 10 feet | 3'0" |
3'9" |
5'6" |
| 12 feet | 2'9" |
3'6" |
5'0" |