Are 2x6 OK for deck joists?

Author: Gracie Bechtelar  |  Last update: Wednesday, June 18, 2025

Yes, you can use 2x6 boards as deck joists, but you must take special care with your deck joist spacing and spans.

How far can a 6x2 span for decking?

so a 6x2 will span 8ft at 400 centres max.

Why not use 2x6 for decking?

2x6 lumber should never be used for joists that span open air. Even on a deck. They're fine for fully supported floors, such as with full-contact rock or gravel bed foundations.

Should I use 4x2 or 6x2 joists for decking?

Minimum joist 4x2 and 1.8m will be fine. Personally if I'm building any sort of raised deck (not sure how much of a slope you're building on) then I use the posts to sport a double bearer on which the joists sit. Overkill but it'll never move and only a little more cost in materials.

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

Commonly used joist sizes are 2-by-6, 2-by-8 and 2-by-10. For example, when you space joists 16″ apart — which is standard for residential decks — a deck spanning 9 1/2′ would require 2-by-6 joists, a 13′ deck would need 2-by-8 joists and a 16′ deck calls for 2-by-10 joists.

Are 2x6 strong enough for deck joists?

What size should joists be for decking?

What Size Joists Do I Need? If it is a standard deck with just a table and chairs sitting on it, 4 x 2" (100 x 50mm) joists are strong enough. However, if you are looking for strength and are putting heavier objects on the deck, we would recommend 5 x 2" (125 x 50mm) or 6 x 2" (150 x 50mm) joists.

How much load can a 2x6 deck joist hold?

Typically, a 2x6 deck board can support around 50 pounds per square foot (psf) when spanning 16 inches on center (OC). However, as the span decreases, the weight capacity per square foot increases. For example, if the span is reduced to 12 inches OC, the load capacity can increase to around 75 psf.

Why are deck boards 5'4"?

This size has become popular for decks due to its balance of strength, weight, and affordability. The term “5/4” reflects the lumber industry's historical way of measuring thickness in quarters of an inch, a system that has stood the test of time.

Do you need blocking between deck joists?

Blocking must be equally spaced in rows, maximum of 4 to 6 feet apart. WHY IS BLOCKING NEEDED? Solid wood blocking will help reduce up or down movement and/or twisting of joists. Limiting joist movement can help reduce excessive gapping and also ensure a more uniform finished surface of your TimberTech Deck.

How far can a 2x6 span without sagging?

“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.”

How far apart should support posts be on a deck?

Your posts should be evenly spaced out and the centre of each post should be no more than 1.8 m apart in any given direction. Corner posts shouldn't be right in the very corner but should be offset to one side by the width of a post. This is to make it easier when you come to installing railings or a balustrade.

What is the best wood for deck joists?

The best timber for decking joists should be a kind that is resistant to moisture, insects, decay, or rot. Timbers like Cedar, Ironbark, Spotted Gum, and pressure-treated pines are good to use as decking joists. That said, if you have the budget, choose composite joists which will not rot, warp, decay or splinter.

Should I space 2x6 deck boards?

When installing new air-dried decking the proper gap ranges from 1/8 inch (3.5 mm) - 1/4 inch (6.5mm) depending on the environment. If you are installing air-dried decking during a rainy or humid season you may want to place the boards with a 1/8 inch (3.5mm) gap.

Does joist tape trap moisture?

Deck joist flashing tape is an affordable and effective way to protect your deck's wood substructure. 1. It helps prevent moisture penetration 2. Helps protect lumber from rot 3.

What is the 3 4 5 rule deck?

Explanation of the 3-4-5 Rule

The 3-4-5 rule uses a triangle with sides measuring 3 feet, 4 feet, and 5 feet to create a perfect right angle. When these measurements are exact, you can be sure your corner is square.

Should you pre drill 5 4 deck boards?

Yes, pre-drill pilot holes to prevent damage to the wood and allow the screw to better fit into the wood. Drilling pilot holes help prevent wood from splintering and cracking when installing screws.

What is the joist spacing for a 2x6 deck?

The span of a 2x6 deck joist depends on your deck joist spacing and material. For instance, a 2x6 redwood or cedar joist can span eight feet at a spacing of 16 inches. On the other hand, a 2x6, 16- or 18-gauge steel joist can span 16 feet, 4 inches if the spacing is 12 inches.

How many screws for 2x6 deck boards?

While there is no fixed rule, a general guideline is to use at least two screws per joist per deck board. This ensures sufficient attachment and minimizes the risk of sagging or warping over time. For narrower deck boards (less than 6 inches wide), it is recommended to use three screws per joist, evenly spaced.

How many joists for a 12x12 deck?

For example, a 12-foot x 12-foot deck of 5/4 x 6 pressure treated wood decking on 16 inches on center spacing of joists will require: A 12-foot long deck with joists 16 inches on center will require 10 joists. 20 fasteners x 26 (number of rows of decking) = 520 fasteners. Add 10 percent to be safe.

What do deck joists sit on?

The joists sit on top of a beam or are attached to a beam using joist hangers. Beams away from the house are almost always supported by vertical posts or columns.

Can you use 2x2 for decking joists?

Stress graded to C16, this timber is well suited to all structural applications. This 2" x 2" is a perfect way to start your new Deck. Strong and easy to work with, you won't need a professional! Please select a length and a quantity, and our calculator will do the rest.

Can deck joists run parallel to a house?

Some decks are designed with a joist orientation parallel to the house. This is useful in cases where you do not want to hang framing members from the house wall. In order to rotate the joist's typical direction, you will need to install beams that project perpendicularly out from the house.

What gap should I leave between decking joists?

Generally, joist spacing for decking boards should be no greater than 450mm, with a recommended spacing of 400mm. It's crucial to ensure that each board is evenly spaced along the length of your decking, creating an even, level walking surface whilst supporting the rigours of foot traffic.

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