Determining the Ideal Pergola Beam Size: Expert Advice

When constructing a pergola, it is recommended to use a pergola beam size that is at least 2 inches by 8 inches.

Although the specific dimensions may differ depending on the intended use and size of the pergola, starting with these measurements is a good general guideline for building a sturdy structure.

Pergolas can be a great addition to a landscape, whether for practical purposes such as providing shade or simply for their aesthetic appeal.

However, before you can enjoy this luxury, it’s important to consider the design-build process and determine the necessary materials to achieve the desired pergola type.

If you’re planning to construct a pergola, there are certain considerations you should keep in mind when ordering your materials.

Firstly, think about the purpose of your pergola and the type of material you want to use.

You should also consider the size of your structure and how much sun you want to block.

Additionally, the type of pergola you’re building will impact the size of your beams.

Read on to discover how to analyze these factors and determine the appropriate size for your beams.

Close up of long beams being used to build pergola showing the best pergola beam size

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The Importance of Choosing the Right Pergola Beam Size

When constructed properly, a pergola can provide years of enjoyment and usefulness for both you and your family.

By utilizing beams of the appropriate size, you can maximize the benefits of this structure, including the desired amount of shade or sunlight and the desired aesthetic appearance.

The suitable pergola beam size will also add life and safety to your pergola to withstand weather concerns and normal wear and tear.

Related Article: 5 Best Tips for Getting Optimal Shade From a Pergola: Direction Matters

Intended Pergola Use

If you plan to use a pergola for shade during the hot summer, wider beams would be a better option to provide more coverage.

However, if you want to create a visually appealing structure for a nice view, the decision should be based on the design aspect and shape of the beam.

If you plan to use a pergola in your garden, you may need to adjust the size of the beams to accommodate better the type of plants you want to grow, particularly those that vine.

This can help optimize their growth potential.

Type of Material Being Used

There are various options for builders to construct a pergola aside from the typical wood material.

These options include vinyl, pressure-treated wood, fiberglass, cedar, PVC, and aluminum, among others.

When choosing beam dimensions, it’s essential to consider the availability of materials and the ease of cutting them to your desired pergola beam size.

While some materials may be readily available and easy to cut, others may be more difficult or expensive to find and cut to a specific size.

Taking this into account can help you make the best decision for your needs.

Related Article: Douglas Fir or Cedar for a Pergola: Choosing the Best Wood

Size of Your Pergola

When selecting beam dimensions for your pergola, it’s crucial to consider the size of the structure.

Common sizes for pergolas include 10′ x 10′, 10′ x 14′, 10′ x 12′, 12′ x 12′, and 12′ x 16′.

You have the option to construct a pergola in any size you desire.

However, the following measurements are commonly used to cover a dining or sitting area without occupying too much space.

Determining the size you want for your pergola will assist you in selecting the appropriate pergola beam size.

When building a pergola, a helpful rule is to have the beams overhang on each side by 1’6”.

To determine the length of your beams, add 3 feet to the overall length of the pergola, ensuring that each end overhangs by 1’6”.

This will give you the correct beam length.


  • A 10’ x 10’ pergola will have 2” x 8” x 13’ beams
  • A 12’ x 12’ pergola will have 2” x 8” x 15’ beams
  • A 10’ x 14’ pergola will have 2” x 8” x 17’ beams

Simply add 3 feet to the desired length of your pergola.

How to Build a Pergola- Main Beams

Sun vs. Shade

When you’re under a pergola, it will only provide a slight shade as it blocks around 20-30% of the sun.

If you want more shade, you can consider widening the pergola beam size.

Before deciding on adding extra width to your pergola, consider its location and whether it would provide more shade under the structure.

If the sun sets on a particular side and you plan to use the pergola in the evening, the additional width may be worth considering.

Types of Pergolas

When it comes to pergolas, there are different types to consider.

You can opt for a standalone pergola or one that is attached to a deck or house.

The type of pergola you choose will affect the amount of support you need to plan for.

Related Article: Types of Pergola Designs You Should Know About

When installing a pergola on grass, it is important to ensure that it has adequate support on all sides to maintain its safety and stability.

However, if the pergola is attached to an existing structure, less support may be required as the additional strength from the structure can contribute to the overall stability of the pergola.

When deciding on the level of support for your structure, safety should be your top priority.

It’s better to err on the side of caution and add more support than necessary.

Related Reading: The 10 Top Reasons for Owning a Pergola

Final Thoughts

Calculating the beam measurements for your pergola is a crucial first step in initiating your design process.

Having the optimum pergola beam size will allow the rest of the project to proceed smoothly.

Though there are many factors to contemplate when making these determinations, the undertaking is feasible and can be completed in a brief period.

Additionally, this process will provide solutions to numerous other inquiries you may have regarding your pergola.

Once you complete this step, a significant portion of your design work will be finished and you can proceed with the purchasing and construction phase of the project.

Pergolas are stunning enhancements that can uplift and invigorate the areas where you want to relax.

Make the process enjoyable and worthwhile, and soon enough, you’ll have your very own pergola to enjoy its perks.

Enjoy living the outdoor life!!!