The importance and use of wood posts in our modern-day construction cannot be overemphasized, from bridge constructions down to rooftops and foundations.

Generally, wood posts come in different shapes, sizes, and qualities. The 6×6 wood post that has found rampant use in cabins and some residential buildings is of concern.

The 6×6 wood post foundation is one brilliant and economical way of constructing foundations. Let’s look into the construction of the 6×6 wood post foundation. 

Generally, wood is a good choice of material when it comes to constructing large structures that are meant to hold weight. Therefore, it is no surprise that you can build a structure on a 6×6 wood post foundation. With proper construction, the stability of the 6×6 wood post foundation is unquestionable, just like the normal concrete foundation.

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How Much Weight Can Go On a 6×6 Wood Post Foundation?

6x6 Wood Post Foundation

The standard load capacity of a 6×6 wood post foundation is approximately 20,000 pounds. 20,000 tons of weight is the peak of any 6×6 wood post foundation, regardless of its quality. 

This much weight capacity is mathematically 15 percent better than the load capacity of a 4×4 wood post. It then means that a higher weight demands the use of a higher wood dimension.

The standard recommended weight by the international building code for a 6×6 wood post construction is 17,000 pounds. 

You may want to wonder why the standard weight load recommendation is lower. Let’s take a look.

It is worth noting that since the 6×6 wood post can hold such a huge weight load, wood material quality varies.

In other terms, it means that the load capacity of the wood post will vary from one to another as per the quality of the wood.

Aside from the quality of the wood post, other factors can affect the load capacity of the wood post.

Termites, ants, and other wood insects are one of the greatest limiting factors to the stability of wood post foundation. Moisture from the ground is another major contributing limiting factor. 

Due to some limiting factors, the wood foundation doesn’t always have the stability to withstand the large weight. 

For this reason, the standard structurally allowed load on a 6×6 wood post foundation is always lower than the actual capacity.

In addition, putting aside the natural limiting factors, other forces such as gravitational force, internal stress, and strain all come into play. 

Too many factors affect the weight capacity of wood post foundation. Therefore, for safety, it is better to allow a minimal weight. Can You Build a Foundation over Tree Roots?

Will a 6×6 Wood Post Foundation Last In The Ground?

The estimated due date for a 6×6 wooden post foundation is around 10 – 15 years. So yes, the 6×6 wooden post foundation will last perfectly well in the ground.

With additional care and maintenance, you will surely have the wooden foundation in the ground even longer. 

So long as the factors affecting the wood’s longevity and other things are checked off, you don’t have any cause for alarm.

However, you must note that the wooden post foundation’s longevity largely depends on the nature of its fixation on the leveled ground

While a wooden post foundation can last long on normal ground, the use of concrete, on the other hand, will increase its durability. 

However, the improvement is only to a certain degree, as wood embedded in concrete has some disadvantages.

The case of moisture rising in the wood from the ground is one of the greatest limitations of the above foundation method.

However, another wood post-fixation method involves using steel material to cover the base of the wood inside the ground. 

To ensure that the wooden post foundation lasts a long time, use metal rebar to cover every wood post inside the ground.

This way, the base of the wooden post escapes the moisture that normally comes from the ground. Plus, the issues of termite and ant-eating up the wood base are grossly minimized. 

With the right thing done, you can surely bank on the durability of the wooden foundation.

The combination of steel rebar fixed in concrete and a well-treated wooden post will serve for up to 25 years. Is It Hard to Hand-Dig a Foundation?

What Size Footing Can You Use With a 6×6 Wood Post Foundation?

According to the IRC (International Residential Code), every 6×6 wood footing should be at least 12 inches wider than the base of the wood. 

Similarly, the base of the footings for the 6×6 wooden post foundation shouldn’t exceed 24 inches in width. 

So, you have 12 inches as lower width and 24 inches of footings as the highest for a 6×6 wood post foundation. 

The strict measure is because the structure’s overall dead and live weight is equally distributed to the footings. 

Any concrete base footing below the required IRC dimensions will result in undue stress within the wood.

It is worth noting that aside from the base footings’ size, the footing’s strength is also important. In every sense, the footing should have a minimum compressive force of 2,500 psi.

Remember that the foundation of every building provides all the structural support and firmness to the building. 

We’ve often heard of a building uprooted by strong winds and storms due to the wacky foundation footing. 

Therefore, to prevent unwanted accidents, I recommend that you strictly adhere to the guidelines of the IRC on post-foundation footings.

Adequate planning and resources are required to construct any size of wood post footings that will stand the test of time. 

Below is a table showing the IRC wooden post foundation size and base footing dimensions. The focus is on the commonly used wood post foundation.

Wood Dimension4×4 Wood Post Foundation6×6 Wood Post Foundation 
Width 8 – 12 inches12 – 24 inches
Depth (below grade level)36 inches or more36 inches or more
Diameter12 inches24 inches

How Deep Should a 6×6 Wood Post Foundation Go Underground?

Ideally, the general rule is that for any foundation post, the depth should be at least one-third of the entire post. 

The stability of the entire structure is hinged on the balance and firmness of the wood post.

Therefore, any 6×6 wood post below the least ideal specified depth will fail upon extra applied pressure.

For better assurance and safety, dig the hole for the wood post into half the length of the wood.

For instance, a six-foot-high wood post, about three-foot high, should be buried underground for firmer support.

However, certain factors, such as soil and local climate conditions, can utter the ideal general rule. Also, the height of your house fence can affect the supposed depth of the wood post.

Due to the above-mentioned uttering factors, a new standard dimensioning is adopted. The adopted formula checks out every factor.

In the 6×6 wooden post foundation’s dimensioning, every footing must be at least 36 inches into the ground.

It is to say that for our six-foot-high wood post, the wood post should be at least 36 inches into the ground. This depth is the least and applies to every wood post dimension. 

The depth of the concrete footing for the 6×6 wood post foundation ought to be so because of soil disturbances. Plus, the deeper, the better the structural construction’s stability. 

It is worth noting at this point that in digging the post hole, the diameter of the hole must be uniform. For a 6×6 wood post foundation, 24 inches is the standard diameter. How Much Should a 12×16 Shed Foundation Cost?

3 Best Uses For 6×6 Wood Post Foundations

We use wood for construction in numerous areas, especially the 6×6 wood post.

The 6×6 wood post has found use in several areas of human endeavor ranging from simple crafts to large structural buildings. 

Below are three common places where the 6×6 wood post finds use.

#1. Structural Constructions

As contained in the article, 6×6 wood posts find use in foundation constructions of residential buildings and the like. 

Some residential buildings’ decks/front corridors have wood as the basic building material. 

Also, some mini bridges, which come in the form of different trusses, have the 6×6 wood post as the construction material.

#2. Interior Constructions And Designs

Another common use of the 6×6 wood post is in interior home and organizational designs. Some homes have the entire interior structure made of wood, 6×6 wood posts, to be precise. 

Staircases, custom-made doors, tables, and doors can all come from 6×6 wooden posts. Similarly, you will often find the 6×6 wood post as the build-up material of some church stage designs.

#3. Simple Arts And Crafts

Simple crafts such as small closets, decorative hose holders, and street light hangers are all examples of crafts from 6×6 wood posts. 

Another excellent example of using 6×6 wood posts is fake food displays and book folds.


Using wooden posts for the foundation in a structural building is a common practice in several parts of the world.

Even though it is rather fragile to use as a structural foundation, it still always measures up to expectation. 

The commonly used wood post type for foundation construction is the 6×6 wooden post.

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