6x6 Beam Span Chart
Use the span tables below to determine allowable lengths of joists and rafters based on size and standard design loads.
6x6 beam span chart. Numbers in blue are joist spans beam to beam or house to beam. A redwood 4x6 beam should span no more than 6 between supporting posts. Repetitive member fb design values are used in design when three or more load sharing members such as joists rafters or studs are spaced no more than 24 apart and are joined by floor ing sheathing or other load distributing elements.
The numbers in gray indicate the distance between the support posts. A double 2x12 beam can span 12 feet. A 2 2x10 can span 10 feet and so on.
You can also use the wood beam calculator from the american wood council website to determine maximum rafter and joist lengths. Dimensional lumber deck beam span chart. Six by six beams can be milled from almost any wood species but only a handful of commonly milled species are readily available.
Refer to the deck beam span table below to assist in determining the maximum span of a given beam between posts. Douglas fir is one of the most widely used and strongest wood species commonly used for six by six lumber sometimes marketed as hem fir or fir larch because of its close association with hemlock and larch spruce runs a close second with respect to wood strength. Obviously the larger the beam the greater the distance it can span between posts.