# Frequent question: What size roof rafters do I need?

Contents
Nominal Size Spaced (o.c.) Species / Grade ( 20# Live Load – No Finished Ceiling)
2″ x 6″ 12 14-2
16 12-4
24 10-0
2″ x 8″ 12 18-9

## How far can you span a 2×8 Rafter?

In general terms, joists spaced 16 inches on center can span 1.5 times in feet their depth in inches. A 2×8 up to 12 feet; 2×10 to 15 feet and 2×12 to 18 feet. The larger the deck, the larger the joists.

## Can I use 2×4 for roof rafters?

You can use either 2×6 or 2×4 rafters for roofs with a 3/12 pitch or greater, but it depends on the overall size of your shed. For roofs that won’t experience heavy snow loads, a gable roof can span up to 22′ with 2×4 rafters.

## How far can 2×6 rafters span?

2-grade 2×6 joists can span up to 10 feet 9 inches from beam to beam when spaced the standard 16 inches apart with a maximum live load of 30 inches per square foot.

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## Are two 2×6 stronger than a 2×8?

In bending, a joist composed of two 2×6’s (true dimension 1.5 inches x 5.5 inches) are slightly stronger than a single 2×8 true dimensions 1.5 inches by 7.25 inches.

## How far can a double 2×8 beam span without support?

long. When supporting joists that span 12 feet with no overhang beyond the beam, a double ply beam can span in feet a value equal to its depth in inches. A double 2×12 beam can span 12 feet; a (2) 2×10 can span 10 feet and so on.

How far can you span a double 2×8 beam?

Header Size Maximum Span Number of Trimmers
Double 2×12 7 ft., 1 in. Two

## What size rafters do I need for a 12 foot span?

Max. Live Load 20 lbs/ft2 (956 N/m2)

Maximum Span (ft – in)
Nominal Size (inches) Rafter Spacing, Center to Center, OC (inches) Lumber Grade
2 x 6 24 13′
2 x 8 12 21′ – 7”
16 19′ – 7”

## Which is better rafters or trusses?

Once in place, rafters use up more wood, so they weigh more, but trusses are stronger because they are more efficient and have the capacity to produce maximum strength using fewer materials in the end.

## How far can a 2×6 Rafter span without support?

How far can a 2×6 Rafter span without support? The table states that 2 X 6 rafters spaced 16 inches on center (o.c) can span a maximum distance of 13 feet 5 inches. Another option are 2 X 8 rafters spaced 24 inches o.c.

## How far can a 2×4 span without sagging?

Generally, 2x4s can extend for up to 20 feet, but a number of issues have to be considered. For instance, the 2×4 would not noticeably sag under its weight at 10 feet.

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## Is 2×4 strong enough?

If there is no strong wind, a 2×4 measuring at least 8 feet can support at least 1,000 pounds vertically. Such calculations would hold if, for instance, the load is square. 2×4 are fine if span was like under 5 ft. … 2×4 are suitable for ceiling joists where the LL is like 20 Lbs.

## Can a 2×4 span 8 feet?

In general terms, joists spaced 16 inches on center can span 1.5 times in feet their depth in inches. A 2×8 up to 12 feet; 2×10 to 15 feet and 2×12 to 18 feet. … If there is no strong wind, a 2×4 measuring at least 8 feet can support at least 1,000 pounds vertically.

## How far can you cantilever a 2×6 roof?

Looking at the table below, we see that 2×6 floor joists can be cantilevered up to 2 feet and 6 inches (2′-6″) when the joists are spaced 16″ apart.

## What is the maximum span for a 2×6 ceiling joist?

For example, the highlighted cell (below) shows that a 2″ x 6″ Southern Yellow Pine joist, with a grade of #2, and spaced 24″ apart can have a maximum span of 10 feet – 0 inches (10-0), if you are designing your structure to support a plaster ceiling.

## Can I use 2×6 for floor joists?

2×6 joists should only be used on ground-level decks that do not require, and will not provide for, any guards. … In bending, a joist composed of two 2×6’s (true dimension 1.5 inches x 5.5 inches) are slightly stronger than a single 2×8 true dimensions 1.5 inches by 7.25 inches.

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