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floor joist span calculator

by Madilyn Wyman Published 3 years ago Updated 2 years ago

What is the maximum span for a 2x10 floor joist?

With 16” spacing, a floor joist can span up to 14’ as long as it is not cantilevered and terminates with support on either end. If the joists are 24” apart, then one 2×10 joist can span up to 11’ 5”. These lengths are for SYP lumber. If you have Spruce-pine-fir lumber, then your span changes to 13’ 7” for 16” joist spacing.

How far can you span a 2x6 floor joist?

The maximum span for a No. 1 quality 2×6 floor joist made from southern pine with a maximum load of 40 psf at standard 16-inch spacing is 10 feet 9 inches, according to the International Residential Code. When we break this down, the variables determining floor joist span are joist spacing, load, wood species, and lumber quality.

What is the longest span for floor joists?

  • Joist spans up to 2.5m - no strutting required
  • Joist spans 2.5m to 4.5m - provide strutting at mid-span
  • Joist spans over 4.5m - provide 2 rows of strutting at third span positions

How to calculate floor joist?

Joist Span Calculator

  • Select a load. There are six choices. The lowest is a plain ceiling joist with no storage (10 pounds per square foot). ...
  • Select the on center spacing for the joists. This is how far apart they will be. ...
  • Enter a span for the joist. This will be slightly less than the length of the board. ...
  • Finally, select a type of lumber. No. ...

How far can a 2x10 floor joist span without support?

With 16” spacing, a floor joist can span up to 14' as long as it is not cantilevered and terminates with support on either end. If the joists are 24” apart, then one 2×10 joist can span up to 11' 5”.

How far can a 2x8 floor joist span without support?

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”. In this guide, we'll explain what span means in terms of construction, factors that impact the span, and how much weight a 2×8 can support.

How far can a 2X6 span for a floor?

A 2×6 can support up to 50 pounds per square foot of weight without sagging with a maximum span of about 12 feet when spanning a distance horizontally, with the 2×6 standing in a vertical position. This number includes both live and dead weight.

What is the maximum span of a 2x12 floor joist?

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.

Should I use 2x6 or 2x8 for deck joists?

You can use 2×6 as deck joists if the deck is low enough to the ground as not to require guard railing. When using S-P-F 2×6 deck joists, the span must not be greater than 9'0″ (2.73m) with joists at 16″ o.c. (400mm), and 9'10” (3.01m)with spacing at 12″ (300mm).

How much weight can 2x8 floor joists hold?

A 2×8 will adequately support a dead load of 20 psf and a live load of 40 psf depending on some factors, including allowable span. This equates to a total load of 60 psf. Therefore, for a 2x8x10, the total load would equal 600 pounds per lineal foot.

Are 2x6 OK for floor joists?

2x6s may be used for floor joists, ceiling joists, or rafters and have differing spans for the same grades and species. Loads are divided into live or snow loads and dead load considerations. A plank used for a floor joist commonly has different load factors than a ceiling joist or rafter.

What size beam do I need for an 18 foot span?

Thus, for a 18 foot span, you will need atleast 3-2×16 or 6×16 size of wood beam. For a 18-foot spans, the wood beam has to be at least 16 inches in depth and 6″ in width (3-2×16) used for residential building, wood frame structure or projects.

What is the load bearing capacity of a wood 2x6?

According to the Codes, a 2×6 on edge with the weight pressing through 5.5” of wood will support approximately 53lbs per linear foot. So, an 8-foot length will support about 424lbs. However, a short span 2×6 on edge can support between 600 and 900lbs depending on wood species, grade, and other factors.

Can a 2x12 span 20 feet?

In general terms, joist or beam which spaced 16 inches apart on Centre can span 1.5 times in feet their depth in inches. A 2×14 can span upto 20 feet. What size beam to span 20 ft:- as per general thumb rule and guidelines, a 4 nailed 2×16 or 4-2×16 or 8×16 size of wood beam can allow to span 20 ft.

What size lumber 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.

How far can a double 2x12 span without support?

A double 2x12 beam can span 12 feet; a (2) 2x10 can span 10 feet and so on.

Part 2 of Residential Structural Design

On this page we will explain how to design with floor joist span tables. At the bottom of this page you'll find a joist span calculator. The content on this page will explain how to interpret the results from the calculator.

Using Floor Joist Span Tables

Continuing on from Part 1: Residential Structural Design Vertical Structural Forces, we were about to start learning about floor joist span tables.

Next Tutorial Section

Now, let's make the house wider so that it is necessary to have a center support for the floor joists. To learn about designing with beam span tables, continue on with the next part of Residential Structural Design:

Floor Joist Span Calculator

To use the joist span calculator below, first select the species of lumber you will use for your construction project from the drop-down list.

What is joist span?

Each joist is one of a series of long, horizontal structures that support the decking itself. While beams are vertical, joists lay horizontally on top of each beam to provide a sturdy, level surface to lay your decking materials across.

Can you use steel joists on a deck?

If you’re building a deck, you’re not solely limited to wood to create joists and framing. Steel joists offer a stronger, straighter, and potentially safer alternative to wood. Even when using the strongest wood to build joists for a deck, that wood is still subject to the elements and can bend, bow, or warp with time.

Is steel joists stronger than wood?

Steel joists offer a stronger, straighter, and potentially safer alternative to wood. Even when using the strongest wood to build joists for a deck, that wood is still subject to the elements and can bend, bow, or warp with time. Steel joists are machine-made, making each joist an identical twin. Similarly, steel will not warp over time, allowing ...

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