The floor joist
Joist
A joist is a horizontal structural member used in framing to span an open space, often between beams that subsequently transfer loads to vertical members. When incorporated into a floor framing system, joists serve to provide stiffness to the subfloor sheathing, allowing it to function as a horizontal diaphragm. Joists are often doubled or tripled, placed side by side, where conditions warrant, such as wher…
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.
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 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.
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. ...
What is the maximum span of a 2x10 floor joist?
Max. Live Load 30 lbs/ft2 (1436 N/m2)Maximum Span (ft - in)Nominal Size (inches)Joist Spacing Center to Center (inches)Lumber Grade2 x 101219' - 10"1617' - 2"2414' - 1"10 more rows
How far can a 2x10 span without support?
How Far Can a 2×10 Beam or Header Span? A 2×10 beam – made up of two 2x10s nailed together – can span up to 11' without support beneath a deck that is 4' wide. For a more normal-sized deck, the same beam can span 8', supporting a deck that is 8' wide. You can also triple a 2×10 beam.
What is the maximum span for a 2x6 floor joist?
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.
What size floor joist do I need for a 12 foot span?
What size floor joist to span 12 feet:- as per general rules and guideline, a 2×6 (2-by-6) size of floor joists made of southern yellow pine, graded as #1 can allows joist spans up to 12 feet for a live load of 30 pounds per square foot and dead load of 10 pounds per square foot when spaced 12 inches apart.
How far can a 2x12 span for floor joist?
In general terms, joists spaced 16 inches on center can span 1.5 times in feet their depth in inches. A 2x8 up to 12 feet; 2x10 to 15 feet and 2x12 to 18 feet. A double 2x12 beam can span 12 feet; a (2) 2x10 can span 10 feet and so on.28-Mar-2020
What is the maximum span for a 2x8 floor joist?
Depending on various factors, the maximum span for a 2×8 floor joist is 16' 6”. The maximum span for roof rafters is 23' 9”. For headers, the maximum span is 11' 2”. Finally, a single deck beam has a maximum span of 5' 11” and double maxes out at 8' 9”.
Are 2x6 strong enough for floor joists?
2 Answers. Show activity on this post. 2x6 joists at the span that you are talking about (16' and 18') are not strong enough to support a floor as a living space. With a span like that the timber size that you sister in would have to be at least 2x10's.27-Jun-2017
Are 2x6 OK for floor joists?
Yes, 2 X 6 lumber can be used for floor joists, but the allowable clear span is only about 4 or 5 feet. Such a small span is seldom useful.
Is 2x6 good for floor joist?
The maximum distance a 2×6 can span, according to the 2018 IRC, for a floor joist, is 12'-6”, ceiling joist 20'-8”, rafter 18'-0”, deck board 24”, deck joist 9'-11”, deck beam 8'-3”, and 6'-1” as for header. Always check the codes for determining factors or consult a Structural Engineer.
How far can you span a 2x4 floor joist?
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.
How far can a triple 2x12 beam span?
of 14 feet for a triple 2x12. 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 2x12 beam can span 12 feet; a (2) 2x10 can span 10 feet and so on.26-Mar-2021
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.
Addition With 12 Ft. Floors and 16 in. On-Center (OC) Joists
Scenario:You are building an addition. One of the rooms is 12 feet. You need to span a distance of 11.5 feet for a live load.Purchase This: 1. Dime...
Addition With 12 Ft. Floors and Joists That Are Spaced Wider
Scenario:You need to span a distance of the same distance, 11.5 feet, for a live load, but circumstances dictate that you can only space the joists...
Addition With 16 Ft. Floors
Scenario:You are building a one-room addition to your house which is 16 feet long. This means that you need to span a distance a distance of 15.5 f...
Short Workshop Floor, 8 Ft. Long
Scenario:You are building a workshop. Your floor joists need to span a distance a distance of 8 feet for a live load.Purchase This: 1. Dimension (I...
Are Floor Joists Hangers Necessary?
Floor joists need to be securely fastened to the wood beams in order to prevent them from swaying or twisting. Whether or not joist hangers are nec...
How to Replace a Rotted Floor Joist in a Crawl Space?
If you have a rotted floor joist in your crawl space, it's important to replace it as soon as possible. If damage to the floor joist is limited, in...
How to Sister a Floor Joist?
A sister joist is used to repair a bad floor joist. However, it can also bridge the span distance between two beams. When repairing a bad floor joi...
Do You Need a Permit to Sister Floor Joists?
In most cases, you don't need a permit to sister floor joists. However, it's always best to check with your local building department to be sure. T...
Which Way do Floor Joists Run?
Floor joists usually run perpendicularly between two load-bearing beams. In some cases, it may be necessary or desirable to run the joists at an an...
How Much Weight Can Floor Joists Support?
As discussed earlier in this post, a floor joist can generally hold between 30 and 40 pounds per square foot (PSF). Floor joists are designed to su...
Can You Notch a Floor Joist?
Floor joists can be notched to fit around obstructions, such as plumbing pipes or ductwork. However, there are IRC guidelines directing how where a...
Are Floor Joists Treated?
In most cases, floor joists are made from untreated lumber. However, there are a few exceptions. If your home is in a moist or humid environment, y...
No. 1 and No. 2 Grade of Douglas fir and maximum span floor joists - imperial units
Maximum floor joist span for No. 1 and No. 2 Grade of Douglas fir are indicated below. Max. dead load (weight of structure and fixed loads) 10 lbs/ft2 . Live load is weight of furniture, wind, snow and more.
Engineering ToolBox - SketchUp Extension - Online 3D modeling!
Add standard and customized parametric components - like flange beams, lumbers, piping, stairs and more - to your Sketchup model with the Engineering ToolBox - SketchUp Extension - enabled for use with the amazing, fun and free SketchUp Make and SketchUp Pro .Add the Engineering ToolBox extension to your SketchUp from the SketchUp Pro Sketchup Extension Warehouse!.
Privacy
We don't collect information from our users. Only emails and answers are saved in our archive. Cookies are only used in the browser to improve user experience.
Advertise in the ToolBox
If you want to promote your products or services in the Engineering ToolBox - please use Google Adwords. You can target the Engineering ToolBox by using AdWords Managed Placements.
Citation
Engineering ToolBox, (2009). Maximum Floor Joist Span. [online] Available at: https://www.engineeringtoolbox.com/floor-joists-span-d_1479.html [Accessed Day Mo. Year].
What is the spacing of floor joists?
The floor joist spacing is the distance between the centers of any two installed joists. See the image below for an example of joists spaced 16" on center (16" o.c.).
Where is the stamped wood on a span table?
Before jumping into the span tables, let's first consider wood species and wood grades. In general, all lumber is stamped near the end of the lumber piece by the manufacturer.
Do you need to do a lot of calculations to determine the size of the structural framing?
Don't worry, you won't need to do a lot of calculations in determining the size and placement of the structural framing within your house design. You will however, need to become familiar with reading your local floor joist span tables for floor beams, floor joists, window and door lintels, ceiling joists, roof joists, roof rafters, and roof ridge beams, as well as the sizing and spacing of wood studs tables.