Can I Use 4×4 For Pergola?

Have you ever searched for whether you can use a 4×4 post for a pergola? I know I have. When is it right to use something like a 4×4 instead of other options? Many people ask themselves these types of questions and often don’t get the information that they need quickly.

So, can you really use a 4×4 post for pergolas?

You can use a 4×4 post for your pergola as long as it is a very small pergola with only 4-6 feet between the posts. 4×4 post might not provide enough load capacity and can be prone to twisting if used on larger pergolas. For the larger ones, the usual 6×6 will provide a better load capacity and will look more proportionate.

How Much Weight A 4×4 Post Support?

A 4×4 post can carry as much as 420 pounds per post. If your load is evenly distributed to the top cross support and there is no bending and twisting of the post, it is safe to say a 4×4 can support a small home size pergola.

Materials For 4×4 Pergola Posts?

A 4×4 post is tough enough to hold up the whole structure of a small pergola. It has enough load capacity and strength to carry smaller pergolas even during harsh weather conditions. But which type of wood is best?

Western Red Cedar and Redwood

Western Red Cedar alongside Redwood is probably the two most popular used timber for pergolas including pergola posts. They are both naturally beautiful and are often assembled together. However, there are still some important distinctions between the two.

  • First, Redwood has a dark red-brown color it while Western Red Cedar is more yellowish in color.
  • Second, Western Red Cedar has a more pronounced and more rustic grain it while the Redwood is more on the subtle side.
  • Both Western Red Cedar and Redwood are insect resistant and doesn’t rot. This allows homeowners to not worry about using harmful chemicals or coating.
  • They are both very sturdy and extremely durable wood material for pergolas. However, Redwood is noticeably slightly stronger.
  • For rustic and a natural look, both kinds of wood are perfect options.

Pressure-Treated Wood

If you are tight on budget, Pressure Treated Wood or PT can be an alternative. This material is very versatile and easy to work with. It is so popular that it can be found in almost every home improvement shop.

Because of the treatment process for Pressure-Treated Wood, it is more resistant to rot, insects, and decay. However, it is important to note that the chemicals used on pressure treating the wood can be toxic and dangerous especially to young kids and pets.

While PT is cheap, it doesn’t equate to looking attractive which is why it is not the first choice for appearance projects. If you use PT for your pergola post, most builders stain it for the best look. Remember, while stain is nice, it has to be maintained and it means more additional expense.

All in all, pressure-treated wood is an excellent choice but it is not as cost-effective as it may seem because of the heavy maintenance involved. Also, the harmful and toxic chemicals should also be considered.

What Is The Best Size Of Post For A Pergola?

There are no hard and fast rules to post size, however, bigger is better. A smaller post will result in more wobble, which could lead to a cracked post and falling debris. The safest bet is to get the biggest posts available but for pergolas, a 6×6 is very common for standard or even bigger sized pergolas.

4×4 versus 6×6?

A 4×4 pergola post or a 6×6 post? The best way to make your choice between a 4×4 and a 6×6 is to compare their advantages and disadvantages. Let’s take a look at the guide below.

Advantages of the 4×4 post are as follows:

  • Cheaper
  • Can save time on a project
  • Easier to work with
  • Perfect for smaller projects

Advantages of the 6×6 post are as follows:

  • The handle more weight
  • Can be used in larger structures
  • More durable and sturdy
  • Perfect for outdoor projects


In conclusion, a good post for a pergola is a strong post. Both the 4×4 and the 6×6 are excellent for almost every pergola project. However, one clear advantage of the 6×6 is that it can handle more weight. In some projects, you may be working with much higher weight and force. For this reason, a 6×6 is always the better choice.

It is not worth taking a chance with a 4×4 pergola post in these cases. It is always good to get bigger posts because of their strength and durability. This is a good way to work with them and also be on the safe side. I would rather get the 6×6 and never have a problem than to settle for the 4×4 and then regret it.