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The Global Insight

Can I use 2×8 for deck boards

Author

Emma Valentine

Updated on March 22, 2026

Q: Can I use 2×8 treated lumber as deck boards? A: No, that’s a not a good idea. Lumber wider than 6 inches should not be used as a flat surface. Wide, flat boards have a tendency to pool rain water, which can lead to cupping problems.

Should deck joists be 2x6 or 2x8?

For upper-level decks, 2×10 is recommended as the minimum size to use for strong guard post connections. 2×6 joists should only be used on ground-level decks that do not require, and will not provide for, any guards. … Most decks use 16″ on center spacing for joists.

What size wood do you use for deck boards?

For the deck surface, you can use 2x4s, 2x6s, or 5/4x6s. The 5/4 decking (pronounced “five-quarter”), available in cedar and pressure-treated fir, is 1 inch thick and 5-1/2 inches wide with rounded edges that make for a splinter-free surface. Cedar 1x lumber usually has one rough side and one smooth side.

How far can a 2x8 deck board span?

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”.

Can you use 2x10 for deck boards?

Editor’s Comment’s: There is certainly no problem using the 2x10s for any of the structural framing of the deck. Using 2×10 treated lumber for decking is another matter entirely.

Can 2x8 be used for floor joist?

The rule of thumb is 1″ of depth for each foot of run. EX an 8′ span should have a 2×8 joist. The same rule of thumb applies to door and window headers but you should use 4x wood.

Can I use 2x8 for deck joists?

2×8 for joists will be fine, with 16″ OC. Should use 2×10 for beams but 2×8 will be fine as well. If you are worried you can triple the 2×8 for the beams but double will be sufficient. You should put the beams at 7 and 14 feet out from the house, with the piers you should do 3 per beam with spacing of 1, 7, 13.

Should I use deck boards or 2x6?

2×6 is thicker and is stronger, but is also more expensive. Spacing between deck boards provide a few critical functions. The primary function is to drain water from the deck. Gaps that are narrow (1/8”), can catch debris, specifically on top of the joists, and can be difficult to clean out.

How much load can a 2x8 support?

Span (feet)Weight Supported (lb)2 x 2″ x 6″2 x 2″ x 8″42250469061680313082660

How far can you cantilever a 2x8 deck joist?

Joist Spacing (o.c.)12″Southern Pine2x103′-1″2×124′-6″Douglas Fir-Larch, Hem-Fir, Spruce-Pine-Fir2x611″2×81′-8″

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How wide is 2x8?

Nominal SizeActual Size2x81-1/2″ x 7-1/4″2×101-1/2″ x 9-1/4″2×121-1/2″ x 11-1/4″4×43-1/2″ x 3-1/2″

What type of wood is best for a deck?

Overall, our experts at Patio Productions recommend Cedar or Redwood as the best wood choice for outdoor decks. If you’re looking for a cheaper option, pressure treated wood is your next best option.

What is the most common deck board size?

The most common or standard deck board width is 6-inch wide planks based on square-foot coverage, labor, and material cost.

How far can a 2x10 span without support?

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.

How far can 2x8 span 12?

Maximum Span (ft – in)Nominal Size (inches)Joist Spacing Center to Center (inches)Lumber Grade2 x 121217′ – 5″1615′ – 1″2412′ – 4″

What size timber do I need for a decking frame?

The frame The key to constructing a good decking area is the frame. If the decking is being built on a low level it should be built of C16 graded treated joists 45 mm by 95mm (4×2 approx.). However if you are building a raised deck you should use 45mm x 145mm joists.

Can I use 2x8 for ledger board?

The best and easiest option is to mount a 2×8 directly to the existing 2×6 ledger board with 3 m10 or m12 3″ screws top/middle/bottom every 16″ on center. This is a common construction practice which I have detailed many times (I work at an architectural/structural firm).

How do you strengthen a 2x8 floor joist?

The best way to strengthen floor joists from underneath is to make a supporting mid-span beam or wall beneath the wobbling joists. Using jack posts or 6×6 posts and 2×10 or 2×8 beams perpendicular to the joists will solve any wobble and ensure your joists never move again.

How do you stiffen a bouncy deck?

To stiffen the deck, go underneath and install a row of 2×8 blocks down the center, perpendicular to the joists. Stagger them with enough room to nail or screw them in place through the end grain, then fasten the treated 2x4s to the underside of the joists so they run from corner to corner, forming an X.

Can I drill a 2 hole in a 2x8 floor joist?

The hole cannot be larger than one-third the depth of the joist, so the maximum hole size for a 2×12 joist (actual size 1-1/2 x 11-1/4 in.) is 3-3/4 in. diameter—plenty big enough for running cable! You can drill the holes anywhere along the length of the joist (first photo).

How much does a 2x8 weight per foot?

Weight of Dimensional Lumber2 x 61.5 x 5.52.342 x 81.5 inch x 7.25 inch3.09 lbs2 x 101.5 x 9.253.952 x 121.5 x 11.254.80

Do deck joists need blocking?

According to National Design Specifications (NDS) blocking is required on any deck joist over 8ft long on 2″x 10″ and 2″ x 12″ material. … Blocking is easier to install it while you are building the deck, as opposed to having to go back and install it after the decking boards are installed.

Can I use 1x6 for deck boards?

Width of material: We recommend only 1×4, 5/4×4 or narrower boards. Never use 1×6 or 5/4×6 material in close to ground applications. Spacing between boards: You must allow space for your deck boards to expand when they take on moisture, as they will inevitably do when exposed to wet weather, rain or high humidity.

Should you leave a gap between deck boards?

Proper wood deck board spacing should have at least a 1/8 inch gap after the decking has dried out. If you install your wood or treated deck boards while they are still wet boards, then they should be attached without a gap between them.

Should deck boards overhang fascia?

When installing decking boards, be sure to allow for enough overhang to cover the fascia board and whatever additional amount you prefer. … This means the installed deck boards should have at least 1.75 to 2.75” overhang before the fascia is installed.

What size boards are used 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.

How far should posts be on a deck?

Layout and Footing Locations In general, posts should be spaced no more than 8 feet apart. Some builders position them every 4 feet for a completely rigid frame. The maximum distance between footings is determined by the size of your joist material.

How many beams do I need for my deck?

While cantilevering can add width to your deck and eliminate the need for additional footings, posts and beams, sometimes it isn’t enough. A 20-foot wide deck, for example, would require two beams: one at 10 feet and one and 20 feet in order to support a deck with 2×8 joists spaced 16 inches apart.

What is a 2x8 board?

2×8. 1-1/2 x 7-1/4. 2×10. 1-1/2 x 9-1/4. 2×12.

How thick is a deck board?

NOTE: Standard boards are often called a 5/4 board when referring to traditional lumber, which means the actual thickness is typically somewhere between 1” and 1 ¼”. Thicker boards are often called a 2 x 6 when referring to traditional lumber, which means the actual thickness is somewhere between 1.2” and 1.5”.

How long is a 2x8 piece of wood?

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