Can You Build A Pergola With Untreated Wood? (Explained)

Pergolas are a popular addition to outdoor living spaces, providing shade and a touch of elegance to any backyard or patio area. One question that often arises when considering a pergola is whether it can be built with untreated wood. 

While untreated wood may be less expensive and easier to work with, it may also be more susceptible to rot, insect damage, and other issues that can compromise the structural integrity of the pergola. 

In this article, we will explore the pros and cons of using untreated wood for a pergola, and provide some tips for ensuring that your pergola is built to last.

can you build a pergola with untreated wood

Understanding The Risks Of Using Untreated Wood

Using untreated wood for building a pergola can be tempting due to its affordability and accessibility. However, it’s important to understand the potential risks and precautions associated with using untreated wood.

One of the main risks of using untreated wood is that it is not resistant to moisture or insects. This means that over time, the wood can begin to rot or attract pests such as termites, which can compromise the structure of your pergola.

Untreated wood may warp or crack when exposed to sunlight and other environmental factors. It’s important to consider these risks before deciding on whether or not to use untreated wood for your project.

When weighing the decision to use untreated wood for your pergola, it’s also crucial to think about the environmental impact. Untreated wood has not been treated with any chemicals or preservatives, making it more environmentally friendly than treated lumber options. 

However, if you live in an area prone to humidity or heavy rainfalls, using untreated wood could lead to faster decay and ultimately require replacement sooner.

Benefits Of Using Untreated Wood For A Pergola

While it may seem counterintuitive, building a pergola with untreated wood can have its benefits. In fact, using untreated wood for your outdoor structure is becoming increasingly popular due to its unique advantages.

Pros and Cons of Using Untreated Wood for a Pergola:


  • A natural look that blends well with the environment
  • Cost-effective option compared to treated lumber
  • Environmentally friendly as it avoids chemicals used in pressure-treated wood
  • Can be stained or painted for added protection against weathering
  • Easy to replace individual boards if needed


  • Prone to rotting over time without proper maintenance such as sealing or staining
  • Attracts insects and pests if not properly sealed or maintained
  • Requires more frequent maintenance than treated lumber options

In terms of environmental impact, using untreated wood reduces the use of harmful chemicals found in pressure-treated lumber. 

Choosing The Right Type Of Untreated Wood

Not all types of untreated wood are created equal and some may not be suitable for outdoor use. When selecting untreated wood for your pergola, consider its durability and resistance to rot and decay. 

Cedar, redwood, cypress, and teak are popular choices due to their natural resistance to water damage and insect infestation. 

On the other hand, pine and fir are not recommended as they are more prone to rotting and warping over time. To help make an informed decision, refer to the table below which compares various types of untreated wood based on their properties:

Types of Untreated WoodDurabilityResistance to Water DamageResistance to Insect Infestation
TeakHighVery highVery low

It’s worth noting that while using untreated wood is a sustainable choice in terms of reducing chemical exposure in both construction workers and end-users, most types require regular maintenance such as staining or sealing every few years. 

This can increase long-term costs compared to treated lumber options. However, if you prioritize eco-friendliness over longevity or affordability then choosing untreated wood is definitely a wise option!

Treating Wood For Longevity

While untreated wood may be used to build a pergola, it is important to note that this type of wood is more susceptible to damage caused by moisture, insects, and other environmental factors. This makes the structure less durable and could potentially lead to costly repairs or replacements in the future.

To avoid these issues, there are several wood preservation techniques available that can significantly extend the lifespan of your pergola. These include pressure treating with chemicals such as copper azole or borate, applying sealants or stains for added protection against water infiltration and UV radiation, or using natural wood alternatives like cedar or redwood which contain their own natural preservatives.

Preparing The Site For Construction

Site preparation is an important step when building a pergola with untreated wood. Before starting the construction process, it’s crucial to prepare the site properly to ensure that your structure lasts for many years without any issues.

Ground leveling should be done before anything else as uneven ground can cause problems later on. One way of preparing the site is by clearing out any debris or vegetation in the area where you plan to build your pergola. This helps create a clean slate and makes it easier to level the ground.

Once cleared, use a shovel or rake to remove any rocks or roots that may affect the stability of your future structure.

Ground leveling also plays a vital role in ensuring stability and longevity of your pergola. To avoid any unnecessary structural issues down the line, make sure that there are no low spots or dips in the ground where water could collect and cause rotting or other damage.

Leveling can be achieved using different methods such as filling holes with gravel or sand or even adding topsoil where necessary to achieve levelness.

3 Ways of Site Preparation

  1. A well-prepared site ensures better accuracy during construction.
  2. Preparing the site minimizes potential hazards while working on your project.
  3. Properly prepared sites give you more control over how long it will take to complete your project.

Preparing your site correctly not only gives you peace of mind but also guarantees the proper functioning of your new addition for many years to come without fear of collapse due to unstable soil conditions underneath.

The Bottom Line

Building a pergola with untreated wood is possible and can be a cost-effective option for those who want to avoid the use of chemicals.

However, it is important to choose durable types of wood such as cedar or redwood and inspect them regularly for signs of decay or insect damage.

It’s also recommended to wear protective gear when working with untreated wood and consider painting or staining it for added protection against weathering.


What Are Some Common Types Of Untreated Wood That Can Be Used For Building A Pergola?

Cedar and redwood are two popular options due to their natural resistance to decay and insects. They also have a beautiful appearance that can enhance any outdoor space.
Cost comparison should also be taken into account as these species tend to be more expensive than other types of untreated wood such as pine or spruce. 
While they may require more maintenance over time, using a less expensive option can still result in a sturdy and aesthetically pleasing structure for your backyard.

How Often Should Untreated Wood Be Inspected For Signs Of Decay Or Insect Damage?

Regular inspection is crucial when using untreated wood in any construction project. Prevention measures should be taken to avoid decay or insect damage, which can compromise the structural integrity of a pergola or other wooden structure.
It’s important to inspect the wood at least once a year and after any severe weather events that may have caused damage. Signs of decay include soft spots, cracks, splits, and discoloration. Insect damage can manifest as holes or tunnels through the wood.

Can Untreated Wood Be Painted Or Stained For Added Protection?

Untreated wood maintenance is crucial to ensuring its longevity. While untreated wood can be painted or stained for added protection, it’s important to note that these treatments will need to be reapplied periodically.

Are There Any Special Precautions That Should Be Taken?

There are certain precautions that should be taken to ensure the safety of those handling the wood, such as wearing protective gear and using specific tools.
Additionally, it’s important to consider the use of wood preservatives to protect against rot, insects, and other damages that can occur over time.

How Does The Cost Of Constructing A Pergola With Untreated Wood?

The cost comparison between the two options can be significant, with treated lumber being more expensive upfront but potentially saving money in the long run due to its increased durability and resistance to decay.
However, there are also alternative options available such as composite materials or metal framing that may offer even greater longevity and require less maintenance over time.

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