What size post should i use for a deck?

Deck posts must be a minimum of 4×4 according to the IRC but many jurisdictions require a 6×6 post as a standard. To avoid code violations, many deck builders choose the 6×6 even if the 4×4 is acceptable.

Should you use 4×4 or 6×6 deck posts?

4×4 post will be fine. I have built many decks for new homes with them. 6×6 is more sturdy of course and will not twist as easy, but for structure purposes, 4×4 will be fine.

What size should decking posts be?

Deck posts are usually 4 feet x 4 inches, 6 feet x 6 inches or 8 feet x 8 inches as determined to be appropriate for the expected load. After determining the width, the maximum deck post height must also be determined. This also depends on the type of wood used.

Should I use 4×4 or 4×6 deck posts?

While there may be a handful of circumstances that only require the minimum 4×4 deck post, you will more than likely want to choose a 6×6 post for the deck. It provides more stability for larger decks, the ability to hold a heavier load, and more room for notching.

Can you use 4×4 post to build a deck?

In the past, many decks were built with 4×4 support posts (also called structural posts). But these can bow seriously, even if a deck is only 3 feet off the ground. For that reason, we strongly recommend that you use 6x6s instead, even if your building department does not demand them.

How many footings do I need for a 12×16 deck?

A standard deck will need four footings parallel to the house, but they will need to be temporarily braced by 6 inch-by-6 inch posts. Using doubled boards, you will then need to build beams on the top row of the posts to frame the edges of the deck. These must be topped with adjustable post caps.


Is a 4×6 post stronger than a 4×4?

4×4’s are quite strong and, other than aesthetics, may be enough for the job. The same goes for a 4×6, but the larger the post, the stronger it will be in compression, when comparing like species. The question is whether that bulk is needed.

How far apart should 4×4 deck posts be?

For Building a Deck Railing, Deck Frame, or Fence

The maximum spacing of 4×4 deck posts should be 6 feet on center, while the maximum spacing of 6×6 deck posts should be 8 feet on center.

Can I use 4×6 for deck post?

Unless you are planning on parking the pickup and the bass boat on the deck, 4x6s are probably enough for the posts. Of far more importance are the stringers, which must be sized for the span and weight they are designed to carry.

Can I use 4×2 for decking frame?

You have enough posts in. You get the joist spacing by laying a length of your 4×2 between the joists which are bolted to the posts. Each end or these joists will be supported by the perimeter 4x2s. Tight fitting noggins in-between will make it all rigid.

How much load can a 4×4 post support?

An 8-foot 4×4 can typically carry 1,000lbs horizontally along its length without excessive sag, or 500lbs in a center load. Supported at 16” centers and the load jumps to 4,000lbs. When used as a post, the same 4×4 can support up to 6,000 PSI and even more if properly braced.

How much can a 4×4 post support?

4×4 can hold up to 4,000 pounds when laying horizontally with the right support. Vertically, a 4×4 should support 4300 pounds but can hold significantly more. The amount of weight that a 4×4 can hold depends on several factors like wood grade, species, and load type.

Should you notch a 4×4 post?

Say “No” to notching pressure-treated deck posts. We want you to build an outdoor railing system that you, your family and guests can enjoy without worrying about safety issues. In order to do so, you need to know this building shortcut is not advisable, and we recommend avoiding it at all costs.

Is a 4×4 post stronger than 2 2x4s?

When used vertically, 4x4s are stronger than two 2x4s. However, if you need a horizontal surface, two 2x4s will be stronger than one 4×4. A 4×4 should not be used horizontally for anything structural. Always be sure that you’re using the proper size and strength of lumber.

How many posts do I need for a 8×12 deck?

The shorter sides—in this case, the 8-foot side—will have 4-feet of distance between deck posts. The larger 12-foot side will have a post spacing of 6 feet at a minimum code requirement. That makes a total of eight posts that need to be installed on this average size deck.

How deep should deck posts be set?

Set footers a minimum of 6” below the frost line for your area to prevent movement during freezing temperatures. Pour about 6 inches of all-purpose gravel into postholes and pack the gravel tight by using the end of a wooden post.

How many posts do I need for a 12×12 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.

How far apart should support beams be on a deck?

How Far Apart Should You Space Deck Joists? The short answer: deck joists are typically spaced either 12 inches or 16 inches apart, on center. (On-center means the length from the center of one joist to the center of the next joist, rather than a gap from edge to edge).

How many joists do I need for a 12×16 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.

What is stronger 4×6 or 2 2×6?

In general, the bending strength of a beam is directly proportional to its width and directly proportional to the square of its height. In the bottom case the 4×6 is theoretically 2² = 4 times as strong as a single 2×6, but since there are two of them it is only twice as strong as two2x6s.

How much weight will a 6×6 post support?

A 6×6 with 12′ span can support 2000 lbs. if you assume a conservative 1400psi bending stress. If you do a good job bonding the two members together, your double 6×6 can support more than 4,000 lbs.

Are 4×4 strong enough for deck?

For most decks, post size is overlooked unless an inspector notices the unusual height of a particular deck. A short 4×4 can carry an awfully big load, and many deck builders use 6×6 posts as a standard, regardless of the height or load of the deck.

How many posts do I need for a 10×10 deck?

A freestanding 10′ x10′ deck needs 4 posts, supporting two pairs of 2-ply non-incised 2×8 beam, upgrading the beam to 3-ply using incised wood.

How do you calculate deck posts?

Draw a line through the mid-span of the joists. Then find the mid-span of the beam that the post supports, and extend lines from there back to the line at the joist mid-span. Find the area within the lines. To calculate the design load for the post, multiply the tributary area by the combined live and dead loads.

How far can you span deck posts?

Ideal deck post spacing is 8 feet or less. The distance between deck support posts depends on the type of wood species used and the size of the joist and beam. There is no minimum span, and maximum spans can reach up to 15′.

How far can 4×6 beam span?

A Redwood 4×6 beam should span no more than 6′ between supporting posts.

How much weight can an 8×8 post support?

That being said, a post can hold a tremendous amount of load! If a particular species of wood can support 1,000 psi, then an 8×8 post can hold 64,000 pounds! The limiting factor (reason to up-size) will likely be aesthetics and/or the number or type of joints needed.

How much weight can a 4×6 beam support?

Assuming it’s “Lodgepole Pine” (Idaho Pine and Ponderosa Pine is slightly less) and it’s grade is a No. 2 and better (no loose or missing knotholes), then a 4×6 spanning 18′ will support about 105 lbs.

Can I use 2×4 for deck joists?

The short answer is yes. 2x4s can work for deck joists. However, they aren’t ideal for spanning long distances without bending or breaking, so you have some limitations. Choosing 2x4s for a low-sitting deck is perfect for keeping your feet out of the mud.

Is 4×2 OK for decking joists?

We recommend beams are constructed from two 44 x 145mm Q-Deck deck joists and are placed at maximum centres of 1.8m. In this instance the maximum span between deck post centres is 2.07m (C16) or 2.24m (C24).

What size timbers do I need for decking?

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.

What is stronger 4×4 or 2×6?

The strength is determined by the load direction. A 2×6 is stronger lying horizontally with the load applied to the 2″ edge facing up. compared to any 4″ side of the 4×4.

How much weight can a 2×4 post support?

In general, a 2×4 can hold a horizontal load of around 20 to 40 pounds per linear foot if the weight is evenly distributed. If the weight is centered between the span, that number could drop to 20 pounds total or less for longer 2x4s. Other factors can increase the weight that a 2×4 can support as well.

Does plywood hold weight?

A 12-by-36-inch piece of 3/4-inch fir plywood can easily support 50 pounds. However, a 12-by-36-inch piece of 1/4-inch thick plywood will not support that much weight. It will only support about 5 pounds before bending.

How do you anchor a 4×4 post?

OZ-POST® WOOD POST ANCHORS – YouTube

Is 6×6 better than 4×4?

6×6 or 4×6 will also give you less traction in specific conditions, than a 4×4. In snow/ice and other low traction situations, you have way less traction. And the exact reason I run a SINGLE rear wheel (not dually) rear on my pickup. Winter traction is FAR better with all the weight on 4 wheels instead of 6.

Can you build a pergola with 4×4 posts?

Support Posts

For a very small pergola with only 4 to 6 feet between posts, 4×4 supports will work. For anything larger, though, the 6×6 stock will not only offer a beefier look and greater carrying capacity, but 6×6 also resists the twisting associated with the more spindly 4x4s.

How far apart should railing posts be?

Spacing of Deck Posts

The two most common sizes used for deck posts are 4×4 and 6×6. When using 4×4 posts, place them no more than 6 feet apart, and when using 6×6 posts, no more than 8 feet apart. The reason for these standards is that the railing system won’t have proper support if the posts are too far apart.

How do you strengthen a notched deck post?

DIY Fix Wobbly Railings (On a Deck or Porch) – YouTube

How do you cut decking around round posts?

Notch Around Deck Posts Like A Boss – YouTube