Building a porch could be a great way to increase the functionality of your outdoor space.

But beyond that, it improves your home’s exterior look and increases its overall value. One big factor you must nevertheless consider is the best roof post to guarantee the stability of your porch. 

The International Residential Code does not spell out if you always have to install a four-by-four or a six-by-six post. Ordinarily, a four-by-four post is alright, but most contractors might recommend a six-by-six post for specific projects because they bear more weight. Let’s look at all you need to know to decide on your porch roof posts.

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What Are 4×4 Posts?    

4x4 Or 6x6 Posts for a Porch Roof

A four × four post is a log of wood fastened above a beam supporting the porch roof.

The dimensions “4 by 4” are 3½ by 3½ inches, but it is preferably referred to as four by four. Now, look at other things you should know about four-by-four porch roof posts.

#1. How Much Weight Can a Four × Four Post Support?

A four-by-four post can typically support weights of 4000- 4300 pounds. But when used as a post, its height determines how much weight it can handle.

A shorter post is more stable and can handle more weight than a longer post of the same material.

A 3 ft tall four × four post can support weights of up to 17,000 pounds. But a taller post of around eight feet would support a lesser amount of 6000 pounds.

An even longer post of 14 feet would support just 2000 pounds. Knowing this is important when considering the overall height of the porch because of the role the porch post would bear in upholding the roof.

In addition, several other factors could affect the potential of a four × four post to support load, for instance, the type of wood.

The stronger the wood, the stronger it would uphold the weight loaded on it. So you should only consider the best quality woods.

#2. What is the Maximum Height Allowed When Using a 4×4 Post?

The International Residential Code allows a maximum height of 8 feet when using a four-by-4 post.

So you also need to factor in the overall porch height since the taller the porch height, the longer the post would be.

And consequently, the less weight it would be able to bear because long posts are less stable compared to shorter posts. 

Longer posts are also more susceptible to stress due to live load, snow load during winter, and unfavorable weather in general.

What are 6×6 posts?    

Six × six posts, which are actually 5½ × 5½ posts, are stronger and more stable logs for roof porches.

They are used widely because of their strength and versatility. Below are some parameters used to judge six × six porch roof posts.

#1. How Much Weight Can a 6×6 Post Handle?

A six × six can handle weights from 10,000 pounds to 20,000 pounds depending on the respective height.

Hence, at 3ft, a six × six can support about 20,000 pounds. At 8 feet, they can support up to 18,000 pounds.

At 14 feet and above, it has a capacity of half of these values at a mere 10,000 pounds.

With a cross-sectional area of 30.25 inches, the 6 × 6 is a resistant beast, prevailing under large loads, stress, and unfavorable weather conditions.

Furthermore, its thicker width makes it less susceptible to bowing due to larger weights. 

#2. What’s the Maximum Height Allowed for 6×6 Posts?

As described above, short posts are more stable and can support more weight than taller posts. As a result, the maximum height allowed for a 6 × 6 is an average value of 14 ft.

#3. Roof Porch Building Codes Regulation 

Summarily, some building regulations to watch out for when building a porch include;

  • Ensure that for a maximum height of 8 feet, you use a four × four porch roof post. And for a height of 14 feet, you use a six × six.
  • Use only treated wooden structures such as porch posts; else, moisture or termite infestation could cause weakness. Such a block of wood is only an accident waiting to happen and could cave in on you when there is an extra load on the porch roof, such as a snow load. 
  • Hence, when building a porch, you must ensure that the wood is decay-resistant and pressure-treated.
  • It would be best if you also treated all holes and notches in the wood with preservatives.
  • All porch roof posts must be well secured above and below to safeguard against lateral movement or other forces.
  • A roof post must be able to withstand both concentric and eccentric stress. That is stress directed towards or away from the center of the post.

Should Deck Posts Be 4×4 or 6×6?    

The kind of deck post you opt for should depend on many parameters. In the past, four-by-four posts were more common and widely acceptable for constructing decks.

However, because they are not very strong or durable, six × six posts are now more acceptable for most deck or porch building projects.

A four × four post is suitable for deck posts up to 8 feet in height and supporting 1 or 2 beams. A six × six can support three beams and cover up to 14 feet in height. 

It would be best if you bore this in mind except otherwise advised by your local building authority.

So you’d also need to check in with authority to be sure that four×four posts are allowed for what you need to do.

Furthermore, if the difference in the cost of 4 × four and a six × 6 is not the main deciding factor, then you should go for the six × six posts. It’s stronger,  more stable, and more durable.

4×4 vs. 6×6 Posts Cost for Porch Roof?

Building a porch generally costs between $15,000 – $35,000. The exact price depends on the type of porch, the design, and the quality of materials used.

Out of this amount, the porch posts for a particular project might cost between $350 to $4000 with installation.

A six × six log is more expensive than a four × four log, starting from about $ 40 compared to $20 per log for a four × four. In addition, the more treated the wood is, the more expensive a log would be.

Overall, the cost difference between both posts is minimal when compared. But the extra stability, security, and strength the six × six possesses cannot be over-emphasized. 

Below is a summary of the various qualities of the four-by-four and six-by-six porch roof posts.

Particulars4 × 4 Post6 × 6 Post
Maximum Load (at 8ft)6000 pounds18,000 pounds
Maximum Height Allowed8ft14ft
Minimum Price (per log)$20$40

Capacity, Spacing, and Weather Resistance Comparison   

Let’s compare 4 × 4 and 6 × 6 posts based on the following parameters.

#1. Capacity

Six × six porch roof posts have more weight-bearing capacity than four × four. At the height of 8 feet, a six × six averages 18,000 pounds while a four × four can handle 6000 pounds.

#2. Spacing

Six × six posts can support thicker beams compared to four ×four. And the thicker the beam, the wider the spacing between posts.

Hence when you’re using 4 × 4, the post would be closer together and might block the outlying landscape more than you would like. But a six × six has a wider post spacing.

#3. Weather Resistance

Six × six posts can withstand weather effects better than four × four. A good example of such weather effects includes snow load.

During the winter, the build-up of snow on your porch roof or deck can cause tremendous stress to the porch posts. 

And if a four × four cannot withstand such weight, it would likely buckle or abnormally thwart the structure’s shape. And in worse cases, it’s a potential danger to you or your family.

Do you know: How To Cut 8×8 Post?


A porch post is largely responsible for the stability of your porch roof and the aesthetic value of your doorway.

While deciding on the type of post to use, you must consider various long-term factors in addition to short-term factors like money.

With all these, a six × six post surpasses a four × four. If money is not the main determinant, you should go for it.

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