You asked: What is roof rafter code?

Rafters must be strong enough to hold the roof sheathing and the shingles. If your local building authority has a rafter-spacing code, you may not space rafters wider than required by code. Typical rafter-spacing codes will specify a minimum spacing of 16 inches, 19.2 inches or 24 inches.

What size should roof rafters be?

Use these two tables for roof rafters with a slope greater than 3″ in 12″.

Nominal Size Spaced (o.c.) Species / Grade ( 20# Live Load – Light Roofing)
2″ x 6″ 12 18-1
16 16-4
24 13-4
2″ x 8″ 12 23-8

What is the maximum span for a 2×6 rafter?

A 2×6 spaced 16 inches apart can span a maximum distance of 13 feet 5 inches when used as a rafter, 10 feet 9 inches when used as a joist, and 6 feet 11 inches when used as a deck beam to support joists with a 6-foot span.

Can I use 2×6 for 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.

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What distance should rafters be?

Roof pitch between 30 and 45 degrees strength class C16

Size of purlins in mm Maximum clear span 1.5m Maximum clear span 1.8m
175 x 63 2.49 2.26
200 x 63 2.84 2.59
225 x 63 3.19 2.91
175 x 72 2.64 2.42

How far can a 4×8 rafter span?

lists 14’6″ as the max allowable span for 4×8 rafter.

How long can roof rafters be?

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 8 12 21′ – 7”
16 19′ – 7”
24 17′

What size rafters do I need to span 20 feet?

As per general rules and guideline, for 10 -12 foot span, generally you need 2″×6″ size of rafter, for 15 -16 foot span, you need 2″×8″ rafter, for 18 – 20 foot span, you need 2″×10″ rafter & for 24 foot span, you need 2″×6″ size of rafter placed at 16″ apart from centre.

What is the maximum span for a 2×4 rafter?

A 2×4 can span a maximum of 6′ 7” when spaced 16” apart and used as a floor or deck joist. When used as a ceiling joist or a roof rafter, a 2×4 can span up to 7′ 3” spaced at 16”, and 6′ 4” when spaced 24” apart. Due to the small spans of 2x4s, they often are not used in horizontal load-bearing capacities.

How far apart do roof trusses need to be?

Roof trusses should be 24” apart, on center. Trusses are allowed to be closer together, at either 12” or 16” on center, but building codes allow for 24” on center spacing without using heavier duty fasteners for truss to wall connections.

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Can you use 7/16 OSB on a roof?

Standard types of wood designed for roof sheathing are oriented strand board, known as OSB, and plywood, the most popular being OSB. Sheets of 7/16-inch thick, without edge support, can be used in an area where the snow load is 30 pounds per square foot.

What is stronger 4×6 or 2 2×6?

In general, the bending strength of a beam is directly proportional to its width and directly proportional to the square of its height. In the bottom case the 4×6 is theoretically 2² = 4 times as strong as a single 2×6, but since there are two of them it is only twice as strong as two2x6s.

Do you need noggins between rafters?

A well-built fascia and soffit run needs a noggin for each rafter foot to stop the soffit from floating and the fascia from swaying. Noggins are also used to get the roofline level in cases where the top of the walls are uneven.

Can rafters be 24 on Center?

(That means it can be used at 24 in. o.c. for rafters or 16 in. o.c. for subfloors.) … tongue-and-groove sheathing, rated 40/20; it can be used for rafters up to 40 in.

How far apart are roof battens?

The minimum overlap is 100mm. If additional fall protection is required on steel sheet roofs, Stratco Ceiling Battens may be fixed intermittently between Stratco Roofing Battens giving a batten spacing no greater than 600mm. Roofing battens are suitable for non-cyclonic conditions up to and including W41 (N3).