Asked by: Nashira Puri
business and finance construction industry

How wide apart should decking joists be?

Last Updated: 23rd February, 2020

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Deck Joist Spacing. For residential decking, the space between deck joists should never exceed 16 inches as measured on center (16 inches between the center of adjacent joist boards). If you prefer a more rigid feel, opt for 12 inches spacing on center. For commercial applications, 12 inches on center is the standard.

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Similarly, you may ask, how far apart should deck joists be?

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. The larger the deck, the larger the joists.

Similarly, how much space do you need between decking? Overall, conventional decking profiles should be installed such that when seasoned, will have gaps between 1/8 and 1/4 of an inch. Look at the ends of the boards and install the decking "barkside" up to prevent cupping. Install decking with 3" pressure-treated compatible deck screws instead of nails.

Just so, how far apart are decking bearers?

Due to the proximity to the ground, ventilation is very important. For this reason, the perimeter of the deck should be kept open. For decking, a minimum spacing between boards of 5 mm is recommended.

What size lumber can span 20 feet?

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

Maximum Span (ft - in)
Nominal Size (inches) Joist Spacing Center to Center (inches) Lumber Grade
2 x 12 24 13' - 2"
2 x 14 12 20' - 10"
16 18' - 0"

Related Question Answers

Christen Niculescu

Professional

How far can a 2x6 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.

Arden Wehnert

Professional

How far can you cantilever a 2x6 joist?

Looking at the table below, we see that 2x6 floor joists can be cantilevered up to 2 feet and 6 inches (2'-6") when the joists are spaced 16" apart.

Edilberto Garitaonandia

Professional

How wide are joists on decking?

Joists are typically made from treated 2-by-8- , 2-by-10- or 2-by-12-inch lumber. The three factors are the species of wood, the space between joists and the space between vertical supports.

Izam Ruger

Explainer

How far can you span a 2x6 ceiling joist?

Joist spacing of 24 inches is allowed for spans between 16 to 20 feet using 2-inch by 10-inch lumber of these three grades.

Shuyi Bartrina

Explainer

Should you leave gaps between decking?

The goal is to have about an 1/8-inch gap (the diameter of an 8d nail) between boards after the decking has dried to its equilibrium moisture content. If the decking is installed wet, as is often the case for pressure treated material, it is best to install the boards tight, letting gaps form as the wood dries.

Weizhong Hettrich

Explainer

How many footings do I need for a deck?

For an attached 12 x 12' deck, you'll need at least 3 footings, plus at least 2 more if you're planning on building stairs with it. If your deck will be a different size, it's easy to figure out how many you'll need.

Manue Hegmanns

Pundit

How far can a beam span without support?

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.

Zidane Lewandowsky

Pundit

Can I build a deck directly on the ground?

Building an 8-by-10-Foot Floating Deck
Floating decks can be set directly on the ground or, preferably, a bed of gravel. But it's best to support the deck on concrete blocks. This keeps the wood off the ground and away from moisture so the wood stays drier and lasts longer.

Mykhailo Shepherd

Pundit

How do you prepare the ground under a deck?

To suppress the growth of unwanted vegetation underneath the deck, the area should be covered with landscaping fabric. First, add a layer of coarse sand for drainage. Then cover the sand with landscaping fabric. Bury the fabric under several inches of gravel.

Anarbella Buchheiser

Pundit

What do you use for deck joists?

Pressure-treated lumber is the logical choice for the structural part of your deck—the posts, joists, beams and other members you normally don't see. Pressure-treated lumber can support more weight and span longer distances than cedar, redwood or other woods commonly used for building decks.

Shannan Macazaga

Teacher

Do you pre drill decking boards?

It is good practice to pre-drill holes prior to using deck screws, to prevent the timber splitting. This is particularly important at the ends of boards.

Ludivina Strassen

Teacher

Should you countersink deck screws?

If you are face-driving deck screws, it is acceptable to “self-countersink” them. Some deck screws even have a little cutter head built into the screw, to facilitate countersinking.

Dovile Grosshausen

Teacher

Do you screw decking at every joist?

The screw length is very important; these screws need to penetrate in the joist by 1-1/2 inches. Once all of the decking is in place, snap a chalk line so that the screws can be installed in straight rows over the underlying framing. Each board should recieve 2 screws per joist, spaced about an inch from each edge.

Tiera Kircheisen

Reviewer

What length decking screws should I use?

Most decking screws are 8-gauge and, while 2 1/2 inches is the minimum length needed to hold decking boards to the joists, 3-inch screws are commonly used to provide extra holding power against the upward pressure of shrinking or warping boards.

Heroina Cherifi

Reviewer

Should I nail or screw deck boards?

kkeilman Answers: Screws are a "superior" fastener over a nail (they have far superior tensile strength)—especially if you're talking about screwing down decking. Using your deck example—you should use nails to attach the joists to the deck framing but use screws to fasten down the decking itself.

Evolet Kleinhofs

Reviewer

Should you space pressure treated decking?

Leave a gap between pressure treated deck boards when the wood is wet. Leave Gap: If the pressure treated wood has been kiln dried after treatment (KDAT), leave a 1/8” gap (the thickness of an 8-penny nail) between the boards when attaching, since the wood will expand slightly over time.

Culita Rui

Supporter

How many screws do I need for 140mm decking?

Then times it by 2 because each decking board need 2 screw to fix it to each joist. I would then times it by 1.1 to add 10% to the total to take into account joins in your deck where 4 screws will be needed to fix to each joist. So you will need 2500 screws to fix 500lm of decking.

Yakira Havana

Supporter

How do I protect my deck joists from rot?

Deck Joists
  1. Cut deck joist barrier tape to the proper length according to your stringer.
  2. When applying to the top edges and board ends of deck joists, center over the joist.
  3. Remove the release paper and press in place.
  4. Firmly wrap and fold the tape over both edge sides of the joist.