# What size are roof timbers?

Contents

## What size should roof rafters be?

Use these two tables for roof rafters with a slope of 3″ in 12″ or less.

Nominal Size Spaced (o.c.) Species / Grade ( 20# Live Load – No Finished Ceiling)
2″ x 8″ 16 16-10
24 13-9
2″ x 10″ 12 24-6
16 21-6

## What size timber is used for roof trusses?

We usually opt for the 35mm thickness in timber when designing standard roof trusses. This could be for Fink Trusses in a house construction or Queenpost trusses for a garage. Meanwhile, the 46mm thickness option is used for attic trusses due to fire regulation guidelines.

## What size should ceiling joists be?

Standard Size of Joists

Though there is no standard joist size for the ceilings in all buildings, most average homes use ceiling joists in a board size of 2-by-6 inches. The range of joist sizes used in homes varies though, between 2-by-4 inches and 2-by-12 inches.

## What size timber do I need for a pitched roof?

Roof pitch between 30 and 45 degrees strength class C24

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Size of purlins in mm Maximum clear span 1.5m Maximum clear span 1.8m
225 x 63 3.60 3.38
175 x 72 2.94 2.76
200 x 72 3.36 3.15
225 x 72 3.77 3.15

## How do you size a rafter?

Determine Length of Common Rafter. Determine Run : Divide the span in half, in our case 24 feet divided by 2 = 12 feet run. This is the horizontal distance the rafter travels to meet the one from the other side.

## How far can you span a 2×6 roof rafter?

How Far Can a 2×6 Rafter Span? A 2×6 rafter can span 14 feet 8 inches when spaced 16 inches apart with No. 1-grade southern pine lumber on a roof with a 3/12 slope or less with a maximum live load of 20 pounds per square foot and a dead load of 15 psf.

## 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.

## What are the 3 types of trusses?

Common types of roof truss

• King Post truss. A king post truss is typically used for short spans. …
• Queen Post truss. A queen post truss is typically a vertical upright with two triangles either side. …
• Fink truss. …
• Double Pitch Profile truss. …
• Mono Pitch Truss. …
• Scissor Truss (also known as Vaulted Truss) …
• Raised Tie Truss.

## How do I calculate roofing timber?

WALL PLATE is the timber/wood that are placed on top of blocks or roof beams as the case may apply, so for the fastest way to calculate this, is to add the entire walls length and divide by 3.6m to know the numbers of pieces you need.

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## What is the maximum span of 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.

## How far can a ceiling joist span without support?

Depending on factors and loads, ceiling joists for an uninhabited attic can span from 10′ with SPF #3 and exceed 26′ with structural select (SS) Douglas fir-larch. Floor joists can span from 7′-1” to 16′-6” for the same lumber. Rafters also span from 6′-7” to 23′-9” with that lumber too.

## Are ceiling joists load bearing?

A joist is a horizontal structural member, running across an open space, that is used to transfer loads to vertical members, typically, floors & ceilings. … This is a sure sign that this wall is structural (load bearing). Most times, if the joists run parallel to the wall, the wall is non-load bearing.

## What size is C24 timber?

C24 Graded KD Regularised Timber Carcassing 47mm x 100mm (2 x 4)

## What is the maximum span for a 2×4 Rafter?

Spacing your 2×4 shed rafters at 24” on center limits the width of your roof. For light load roofs, 24” o.c. 2×4 rafters can span up to 7 ⅔’. For heavy loads, 2x4s can span up to 5 ½’. Most roof framing is 24” on center, and you can still build sheds up to 14′ with 2×4 rafters at 24” on center.

## Is a single pitch roof cheaper?

Whereas a hip roof and other popular roof types have at least two sides, the shed roof has a single slope that can vary in steepness depending on the design. … It’s a simple and inexpensive way to roof the newer section.

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