Thus 2″×6″ size of ceiling joist made of #2 spruce – pine- fir can allow span up to 14 feet when spaced 16 inches apart with maximum ceiling loads are assumed to be 20 PSF and roof pitch is not steeper than 3 in 12.

How far will a 2×10 ceiling joist span?

A #2-2×10 joist can span between 11′-5” and 18′-0”, as a rafter between 13′-9” and 21′-7”, and as a beam 3′-6” and 13′-0” or more. The span depends on spacing, lumber species, and grade, and for a beam, the lamination thickness, as well as numerous other factors.

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





Example: The highlighted cell (below) shows that a 2″ x 6″ Douglas Fir joist, with a grade of #2, spaced 24″ apart, can have a maximum span of 10 feet – 8 inches (10-8).

How far can a 2×8 rafter span?

Max. Live Load 60 lbs/ft2 (2873 N/m2)

Maximum Span (ft – in)
Nominal Size (inches) Joist Spacing Center to Center, OC (inches) Lumber Grade
2 x 8 12 12′ – 3”
16 11′
24 9′

How long can a 2×6 rafter span?

Depending on the factors, a 2×6 rafter can span between 4′-11” and 18′-0”, which is a rather large difference. The span decreases as the spacing and load increase and is dependent on the type and grade of timber. The stronger the species and higher the grade, the farther it can span.

Can a 2×6 span 14 feet?

What is this? 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 many rafters do I need for a 16 foot span?





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.

How big of a beam do I need to span 16 feet?

For a 16 foot span, you will need atleast 3-2×14 or 6×14 size of wood beam. Thus, a 3 nailed 2×14 or 3-2×14 or 6×14 wood beam can allow to span 16 feet. For a 16-foot spans, the wood beam has to be at least 14 inches in depth and 6″ in width (3-2×14) used for residential building, wood frame structure or projects.

Can a 2×10 span 16 feet?

How Far Can a 2×10 Span Without Support? An SYP (Southern Yellow Pine) 2×10 lumber span can reach up to 14′ when used as a joist with 16” spacing. If using SPF or Redwood lumber, then the span maximum for the same distances will be half to a full foot less.

What size roof joists do I need?

Roof pitch between 22.5 and 30 degrees with rafter spacing strength class C24

Size of rafters in mm 400mm 600mm
100 x 47 2.13 1.98
125 x 47 2.80 2.58
150 x 47 3.47 3.19


What size lumber can span 14 feet?

What size lumber for a 14 foot span:- as per general thumb rule and guidelines, for a 14 foot span, you will need atleast 2×8 size of lumber/ floor joist when spaced at 16″ apart. Thus, a 2×8 size of lumber can allow to span 14 feet.

Can a 2×8 span 14 feet?

Span is determined by species, grade, dimensions, spacing, use, and load. A rule of thumb is 1.5 times a joist’s depth but in feet when spaced at 16” centers. In general, a 2×8 will span 1.5 x 8, so 12-feet. Based on all factors though, a 2×8 joist span is 7′-1” to 16′-6”, and a rafter 6′-7” and 23′-9”.

Can a 2×12 span 16 feet?



A 2×12 (2-by-12) floor joists can span up to 23 feet 3 inches, 2×10 (2-by-10) up to 19 feet 1 inches, 2×8 (2-by-8) up to 15 feet & 2×6 (2-by-6) up to 11 feet 4 inches at 16″ spaced by using southern yellow pine graded as #1 when live load of 30 lbs/ft^2 & dead load of 10 lbs/ ft^2.

How far can 2×12 rafters span?

How far can a 2×12 rafter span without support. Maximum allowable span for a 2×12 rafter:– the maximum allowable span for 2×12 rafter is 33 feet 5 inches when spaced 12 inches apart from centre, 30 feet 0 inches at 16″ OC & 25 feet 10 inches at 24″ OC with best quality No.

How far can a double 2×12 span without support?

12 feet

A double 2×12 beam can span 12 feet; a (2) 2×10 can span 10 feet and so on.

How far can a triple 2×12 span?



How far can a triple 2×12 beam span:- as per general rules and guidelines, #2 grade southern pine of a triple 2×12 deck beam can span upto 15 feet when total load of 50 psf (40 psf live load + 10 psf dead load) with deflection limit L/360.

How far can a 4X12 span without support?

Dimensional Lumber Deck Beam Span Chart

Joist Spans
Douglas Fir-Larch, Hem-Fir, Spruce-Pine-Fir, Redwood, Cedars, Ponderosa Pine, Red Pine 4X10 8′-4″
4X12 9′-8″
3-2X6 6′-5″
3-2X8 8′-3″

What size header is needed for a 12 foot span?

How far can a 4×12 header span:- as per general rules and guidelines, nominal size of a 4×12 header can span upto 12 feet. Thus, 12 feet is maximum allowable span for 4×12 size header. Therefore, for a span upto 12 foot, you needed 4×12 size header. 4×12 size header is needed for a 12 foot span or opening.