SOLVED! - 4×4 Vs. 6×6 Deck Post: Rundows

To build a deck, today’s homeowners have to take various things into account and one of the most important considerations is the deck post. Responsible for the stability of the entire structure, the deck post determines the result of the project as a whole. At the moment, once it comes to deck post for deck, people have two choices: 4×4 and 6×6. With different projects having different characteristics, the topic of 4×4 vs. 6×6 deck post captures the interest of many.

An Analysis Of Sizes Of Deck Posts 

Expanding Foam for Deck Posts - Anchor Foam for Decks | Fast 2K™Plan to build a deck but cannot make up your mind between 4×4 and 6×6 for the deck post size? Then this article is going to be of use to you. Down below is everything that you must keep in mind about the sizes of deck posts.

4×4 And 6×6: Overviews 


In case you don’t know, 4×4 deck posts don’t have the dimensions that match their name. In reality, a 4×4 deck post is just 3.5×3.5 but even though people know that, the name 4×4 sticks as it sounds better. Usually, 4×4 deck posts extend upward to support beams while being secured to metal brackets set in deck blocks. Regulations for decks vary from place to place but on average, the height limit for 4×4 deck posts is 8 feet.

About load capacity, depending on the height, 4×4 deck posts could support from 5,800 to 17,500 pounds. It’s worth pointing out that as the height of deck posts increase, their load capacity decreases. As a result, short deck posts work wonders once it comes to supporting heavy loads. Of course, with proper bracing, long deck posts should work as well as short ones.


Similar to 4×4 deck posts, 6×6 deck posts have slightly smaller dimensions than what their name suggests. At 5.5×5.5, 6×6 deck posts still prove bigger than their 4×4 counterparts by a considerable margin which influences a multitude of characteristics. To prevent twisting, homeowners would connect one end of 6×6 deck posts to deck blocks with metal brackets and the other to beams. At the moment, the maximum allowable height for 6×6 deck posts is 14 feet.

At its height limit, 6×6 deck posts should be able to hold up to 10,500 pounds with relative ease. The load capacity of deck posts of the size doubles at their lowest height: 21,000 pounds at 2 feet. All in all, in terms of load capacity, 6×6 deck posts don’t differ much from 4×4 ones when the height stays below 3 feet. However, when the height exceeds 3 feet, people rate 6×6 above 4×4 regarding the amount of weight deck posts could accommodate.

A Comparison Of The Sizes 


In general, a wide range of factors influences the durability of deck posts in use from materials to elements. Assuming that homeowners take precautions, 4×4 and 6×6 deck posts would be durable enough to keep twisting at bay. Nonetheless, owing to the differences in dimensions of the sizes, it’s safe to say that 6×6 is more resilient to twisting than 4×4 under loads. Because of that, those who care about the longevity of their projects believe 6×6 to be the winner in 4×4 vs. 6×6 deck post.


To put it plainly, the bigger the deck posts, the easier to make notches during the construction of decks. Needless to say, for notching, many modern homeowners favor 6×6 over 4×4 owing to the space that they have to work with. After the notching warps up, 4×4 deck posts barely have anything left while 6×6 ones still have some space to spare. Of course, people always have the option of bolting the boards to deck posts but such a practice may not pass the local security inspections.


The dimensions of 6×6 deck posts mean detecting signs of damages is a walk in the park by all accounts. On the other hand, if people go for 4×4, they have to spend a lot of time and effort on inspection. In addition, damages to 4×4 deck posts require quite a bit of work to repair compared to that of 6×6 ones. Naturally, for homeowners that happen to have tight schedules, 6×6 is the one that comes out on top in 4×4 vs. 6×6 deck post.


6×6 deck posts consume more materials to produce than their 4×4 counterparts which is why they cost more. As the size of decks increases, the number of deck posts to install rises accordingly so the choice of size would determine the total cost. By choosing 4×4, it’s possible to save a couple of bucks for other needs in the short term. However, since 6×6 deck posts last longer, they help cut down repair/replacement expenses in the long run.

Choosing Between 4×4 And 6×6: Suggestions

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It’s hard to reach a conclusion about 4×4 vs. 6×6 deck post without factoring in individual settings. To ensure that you could choose the right size of deck posts for the right projects, you should check out these hints.

  • Keep regulations in mind: A lot of areas accept the use of 4×4 vs. 6×6 deck posts but some only allow the latter. That is why many contractors opt for 6×6 even though 4×4 is adequate for their projects to avoid regulatory violations. In any case, it’s strongly recommended that you take a look at the local regulations for decks. By doing so, you don’t have to worry about getting into trouble with the law as you build your deck.
  • Think about the load: Once it comes to choosing deck posts, load requires special attention. It’s noteworthy that while calculating the load, you have to look beyond the weight of the decks. For instance, if you live in a region that sees a lot of snow, you have to take snow build-ups into account. Additionally, you have to consider the weight of furniture you intend to place on your deck too.
  • Give wallet some thought: Want to build a deck on a small budget? Then you should choose 4×4 for the size of deck posts. Conversely, if you have money to spend, it’s a good idea to include 6×6 deck posts into your project. Remember that choosing the more costly option today could lead to big savings in the future.


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Do I have to seal deck posts?

Generally speaking, sealants could protect deck posts from moisture which minimizes the odds of rotting as time passes by. Because of that, if you have the time, you have to think about sealing the deck posts of your deck.

How long would deck posts last?

All sorts of factors affect the lifespan of deck posts and that means it changes from case to case. That being said, most deck posts should hold together for decades in normal conditions.

Is it possible to repair damaged deck posts?

Depending on the extent of damages, you could repair damaged deck posts via a number of ways. However, if the deck posts suffer extensive damages that compromise their structural integrity, it’s best to replace them immediately. After all, it only takes one damaged deck post to weaken the support for the deck so don’t hesitate to play it safe. The replacement of deck posts is a straightforward process but feel free to leave it to the pros if you lack confidence.


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