What Is Pressure Treated Wood? Unlock the Secrets of Durable Wood

Pressure treated wood is often utilized in construction and home improvement tasks as it is processed to withstand rot, decay, and bugs – making it great for exterior usage.

In this blog article, I will answer the question what is pressure treated wood and go deeper into its advantages, disadvantages, how it is made, and more.

Pressure-treated wood is a reliable and long-lasting option for outdoor use because it has been made impervious to rot, decay and pest damage through the application of preservatives. This is achieved by subjecting the wood fibers to high pressure, which permits the preservative to penetrate deeply.

Discover the manifold benefits of this type of wood and learn the essential steps to maintain its sturdiness!

If you are looking to build something or just substitute some degraded timbers around your residence, then this article is essential reading for you.

Keep on reading to uncover all the facts you need to know about this popular material!

Disclosure: At zero cost to you, I may get commissions for purchases made through links in this post. I earn from qualifying purchases as an Amazon associate. Products featured are selected based on quality, performance, and reputation, regardless of affiliate relationships.

What Is Pressure Treated wood?

You could already read a short answer to the question what is pressure treated wood in the intro. Here I will go deeper into detail.

The wood that is treated under pressure is a type of timber that has been infused with chemical preservatives to shield it from rotting, decomposition, and destruction caused by pests like termites.

What Is Pressure Treated Wood
What is pressure treated wood

In the process of treating, these preservatives are forced into the wood fibers with great pressure, making sure they are absorbed properly into the wood.

This makes this type of wood suitable for outside utilization and scenarios wherein the wood is prone to exposure to wetness or insects.

Ebook part 1 woodworking basics

How Can I Differentiate Treated Lumber?

It is possible to distinguish treated lumber from other woods in various ways.

  • Labeling or Stamp: The law requires treated lumber to be prominently labeled or stamped with details about the type of treatment and preservatives used. This information is provided to ensure that customers are fully informed before buying the product.
  • Color: The distinctive greenish tinge of this wood is a result of the chemical preservatives used in the treatment process. Although this hue may fade over time, it can help to distinguish the lumber from others, even when the timber gets older.
  • Weight: Treated lumber is generally heavier than untreated wood, as the chemical preservatives applied to it add weight. However, this is not always dependable for identification, as the mass of wood may be impacted by other factors too.
  • Texture: The chemical treatments used in the processing of treated lumber may result in a different texture compared to that of untreated wood. This could be another way to distinguish between them, however, it is not always an accurate indicator as the textures of timber can differ for other reasons too.
What Is Pressure Treated Wood
You can differentiate treated wood based on its label and color

Conclusively, the most reliable means of discerning treated lumber is to check the tags or stamp on the board’s end.

This will demonstrate what kind of treatment was applied and which chemical preservatives were utilized.

Types of Pressure Treated Lumber

Various kinds of pressure treated lumber exist, each utilizing a distinctive chemical preservative.

  • Chromated Copper Arsenate (CCA): This particular chemical preservative utilizing copper, chromium, and arsenic was one of the first used for treating wood. CCA proved effective in protecting wood from deterioration and pests, however due to health and environmental apprehensions related to its arsenic content, it has been substantially phased out.
  • Alkaline Copper Quaternary (ACQ): This form of protection utilizes a combo of copper and quaternary ammonium compound to preserve wood from rotting and bugs. ACQ is a greener option than CCA, regularly seen in both domestic and commercial building.
  • Copper Azole (CA): Protecting wood from deterioration and pests, this treatment consists of a combination of copper and azole compounds. An additional eco-friendly substitute to CCA is CA, frequently employed on decks, fencing, and other outdoor constructions.

When selecting pressure treated lumber, it is essential to consider the kind of treatment employed and the particular characteristics of the chemical preservatives utilised; this will have an effect on the wood’s performance and its appropriateness for a particular purpose.

In addition to these customary sorts of pressure-treated lumber, there are also other proprietary treatments that some suppliers offer.

Grades of Pressure Treated Lumber

What Is Pressure Treated Wood

The three primary categories of pressure treated lumber based on quality and appearance are:

  • Standard (also known as #2): Standard grade pressure treated lumber is ideal for numerous construction and do-it-yourself endeavors. It may exhibit knots, fissures, and other minor blemishes but is still sound in structure and suitable for the majority of purposes.
  • Select: This high-quality Select grade pressure treated lumber provides a uniform, blemish-free look and is ideal for projects that require a polished and consistent finish. Although it may be slightly more expensive than standard grade lumber, it is worth the extra cost if you desire an impeccable result.
  • Premium: Premium grade pressure treated lumber is the best of its kind. Perfection and consistency are guaranteed since it has no knots, splits, or any other defects. Although it is expensive, it is required for intricate projects wherein its visual appeal is of prime importance.

When selecting wood that has been treated, take into account the particular requirements of your project and the resources available.

Typically, common grade lumber will suffice for most building and DIY works; however, if aesthetics are a priority, opt for select or top quality lumber.

Pressure Treated Lumber Sizes

What Is Pressure Treated Wood

Pressure-treated timber comes in diverse sizes to meet the needs of a multitude of construction and DIY endeavors. Common measurements of pressure-treated lumber are:

  • Nominal dimensional lumber: The lumber’s original dimensions are often 2×4, 2×6, and 2×8 before it has been sanded or planed. These are frequently referred to as common nominal dimensional lumber sizes.Actual dimensional lumber: This is the size of the lumber after it has been planed or sanded. Actual dimensional lumber sizes are typically smaller than nominal dimensional lumber sizes, and may vary depending on the specific species of wood used.
  • Decking boards: Pressure treated lumber is commonly found in two sizes: 5/4×6 or 2×6, and is ideal for constructing decks, porches, and other outdoor structures.
  • Fence boards: Fence boards treated with preservative chemicals usually come in 1×6, 1×8, or 2×4 dimensions and serve as building materials for fences and other outdoor edifices.

It is essential to take into account the exact specifications of your undertaking and the size of the lumber you need when selecting pressure treated lumber.

The range of sizes may depend on where you are and the specific kind of wood utilized, so it is wise to consult with your local lumber provider to identify what sizes can be obtained.

When to Use Pressure Treated Wood (And When Not To)

Pros of pressure treated wood

  • Durability: Chemical preservatives are used to treat the wood, which results in it being durable and resilient against decay, rot, and insect damage – making it a suitable material for exterior structures.
  • Affordability: This wood is highly cost-effective in comparison to other materials such as composite decking and PVC decking, thus making it an attractive choice for many homeowners and contractors.
  • Easy to work with: Due to its ease of cutting, shaping and installation, this type of wood is a prefered material for amateur constructors, home remodelers and DIY enthusiasts.
  • Versatile: It is an incredibly versatile material for constructing outdoor features such as decks, porches, fences, and retaining walls. It provides a great option for all your exterior building needs.
  • Widely available: Pressure treated lumber is abundant and can be accessed at most lumber suppliers and home improvement stores, thus making it simple to procure for your endeavor.

Cons of pressure treated wood

  • Chemical exposure: Wood treated with chemicals such as chromated copper arsenate (CCA) must be handled carefully as it can be dangerous to humans and the environment if not properly managed.
  • Weathering: Over the course of time, this type of wood may become dull and discolored due to weathering, particularly if not treated with a protective finish such as paint or sealer on a regular basis
  • Shrinking and warping: Over a period of time, this wood can contract and distort, especially if it is not sealed and guarded correctly against moisture.
  • Higher cost of disposal: This wood is deemed hazardous, necessitating special handling and disposal procedures, thus incurring additional expenses.

What is pressure treated wood used for?

Pressure treated lumber is a widely preferred option for erecting outdoor structures due to its effectiveness in keeping off damage brought by decay, insects, and rot.

This form of wood has been protected with chemical preservatives, making it an ideal selection for applications such as:

  • Decks: this type of wood serves as a popular selection for crafting backyard decks due to its affordability and resilience. Homeowners may stain or paint the lumber to match their abode’s exterior, while it is also effortless to manipulate, making it an ideal choice for do-it-yourselfers.
  • Porches: Pressure treated lumber is an ideal material for constructing porches, whether it be used for flooring, railings, or accents.
  • Fences: Pressure treated lumber is widely used for the construction of fences, especially for exterior areas such as gardens and yards. The wood is tough and can be decorated with paint or a stain to fit the look of the house.
  • Retaining walls: Pressure treated lumber can be employed for constructing retaining walls, which serve to impede the erosion of soil.
  • Outdoor furniture: Pressure treated lumber can be used to construct outdoor fixtures such as benches, chairs and tables.
  • Landscaping: Pressure treated lumber is commonly employed for landscaping purposes, for instance, flowerbeds, elevated beds and borders.
What Is Pressure Treated Wood
Fence – Source: The home depot
What Is Pressure Treated Wood
Deck – Source: The home depot
What Is Pressure Treated Wood
Raised flower bed – Source: The home depot

Wood that is threated under pressure is a versatile option for adding outdoor structures, making it a sought-after choice for homeowners, builders, and contractors.

Nonetheless, great care must be taken when working with this kind of timber as the chemicals used to make it are potentially hazardous if not managed properly.

When not to use pressure treated wood

In certain circumstances, pressure treated wood may not be the ideal choice, such as:

  • Indoor Use: It is not advised to use this type of wood for indoor structures due to the hazardous nature of the chemicals used for treating it, which can be unsafe for both humans and animals.
  • Food preparation areas: It is not recommended to utilize pressure-treated timber for food-related purposes, like chopping boards or countertops, since the chemicals in it can seep into the edibles and cause hazardous health effects. More info in my article The Complete Guide to What Kind of Wood is Food Safe
  • Raised garden beds: Pressure treated lumber contains potentially hazardous chemicals, hence it is inadvisable to utilize it for building raised planting beds which will be used for cultivating edible produce.
  • Sensitive ecosystems: Wood that has been pressure-treated should be avoided in delicate ecosystems such as wetlands, as the chemicals may adversely affect the wildlife and plant life therein.
  • Areas with frequent contact with skin or clothing: People should avoid using pressure treated timber in areas that often come in contact with human skin and clothes, as the chemicals present in it can be easily transferred and absorbed through these materials.
  • Alternative materials available: Considering the environment, it would be more suitable to opt for composite decking or PVC decking, as opposed to these woods if those alternatives are available.

Before selecting wood for any project, one must take into account its intended use, installation site, and ecological impacts. It might be sensible to seek advice from an expert before making a decision in certain scenarios.

How Pressure Treated Wood is Made

preserved wood is a form of timber that has undergone a process of preservation in order to protect it from rot, decay, and insect infestations.

The wood chosen is typically spruce, fir or pine and must be without knots or bends.

Subsequently, it is dried to a humidity of 20% or less which permits the preservative solution to effectively penetrate into the wood.

This solution can be implemented through a pressure-treating method or by immersing the wood in it for an established length of time.

What Is Pressure Treated Wood
The wood is vacuumed in a large impregnation boiler, where an impregnation agent is added

Then, indications like type of preservative employed, manufacturing plant and date of treatment are stamped on the treated lumber to ensure its aptness for usage.

After that, drying out is conducted once more in order to minimize its moisture content as well as augment its stability; lastly, it’s transported and presented to customers for constructional or carpentry projects.

It’s essential to handle such wood with appropriate caution as the chemical substances used during the course of treatment can be detrimental if not dealt with properly.

Before usig this type of wood, it is best that the wood has the right moisture level. If not you can dry the wood at home.

In my article How to Dry Pressure Treated Wood – 2 Effective Ways you will learn all about it so you can get started with perfectly dried wood and avoid problems in the future.

Frequently asked questions about pressure treated wood

How long will pressure-treated wood last?

The expected lifespan of this type of wood is usually between 15 and 20 years, however this may vary depending on the weather conditions and nature of use.

Consider wood of this type of word as wood with a durability class 2. You can learn more about the durability classes in my article A Clear Guide To Durability Classes Of Wood + Chart

Maintenance practices such as the use of safeguarding coatings, regular cleaning, and upkeep can potentially prolong its longevity. Ultimately, the exact life expectancy for a particular wood product must be established individually.

Does pressure-treated lumber rot?

Pressure treated lumber is typically utilised for safeguarding against rot, decay and insects; however, it is not completely immune to these issues.

Pressure-treatment can protect the wood from decaying in even the harshest climates, but it can still succumb to an accumulation of moisture or inadequate ventilation over time.

Furthermore, preservative chemicals may not penetrate deeply enough into certain areas of the wood, leading to rotting at the ends.

To guarantee that pressure-treated timber remains in prime condition and resists deteriorating, adequate maintenance techniques and materials should be used.

While wood that has been treated under pressure will offer greater protection from rot than untreated timber does, proper precautions should still be taken for maximum efficacy.

Do I need to seal pressure-treated wood?

Sealing this type of wood is not always necessary, but it can help to prolong its life and improve its esthetic. The preservatives typically used in the treatment process shield the wood from rot, decay, and bug damage.

Nevertheless, sealing the wood can supply extra protection against moisture and weathering as well as amplify its coloration and give it a polished appearance.

However, it’s vital to keep in mind that not all pressure treated woods need sealing; some sorts of wood preservatives may provide sufficient protection without the need for sealing.

If you are uncertain if you should seal your pressure-treated wood or not, it is advisable to ask an expert or refer to the manufacturer’s instructions.

Generally speaking, wood that has been treated under pressure that will be exposed to nature’s elements or will be utilized in excessively wet places might benefit from being sealed.

Can I put pressure-treated wood in the ground?

This type of wood is ideal for outdoor projects and can be used in the ground as long as it is suitable for the job and all local regulations are adhered to.

For even better performance, use ground contact rated pressure treated wood, which is treated with a higher preservative concentration.

Utilizing appropriate protective coatings such as paint or sealant can also help extend the life of your timber used where it is in direct contact with soil.

It’s imperative to follow both manufacturers instructions as well as local building codes while using pressure-treated wood underground.

Do I need to use special fasteners for pressure treated lumber?

When working with pressure treated lumber, it is essential to use specific fastening solutions, such as hot-dipped galvanized nails or screws, in order to avoid corrosion or staining of traditional fasteners like plain steel nails or screws.

Sometimes, stainless steel fasteners might be recommended for this particular type of wood.

It is important to adhere to the manufacturer’s instructions and local building codes when deciding which fastener to use, as the exact requirements may differ based on the type of wood and its intended purpose.

Using suitable fasteners will ensure a strong and secure connection and will extend your pressure treated lumber’s lifespan.

Is treated wood as strong as regular wood?

The strength of treated wood is broadly similar to that of regular wood, given the same species and grade.

The treatment process does not reduce the structural integrity of the wood, but preservatives used can decrease its dimensional stability.

This means it may shrink or swell more than untreated wood, particularly when exposed to changing moisture conditions.

To guarantee best results, it is essential to select the right type and use suitable techniques and materials.

In summary, preserved wood has the potential to be just as strong and steady as ordinary wood – when utilized suitably.

Are Pressure Treated Woods Safe in Garden Beds?

Using preserved wood in your garden beds is possible when you consider the type of wood, the treatment process, and its intended use.

Some pressure-treated woods may contain chemical toxins that can seep into the soil and affect your garden beds and the nearby environment.

Nonetheless, newer treated woods utilize less hazardous preservatives which are less likely to spread into the soil.

Selecting the right kind of pressure-treated wood for your project and following local building codes is imperative when utilizing these timbers in a garden bed.

Applying protective coatings like paint or sealant not only reduces potential toxic exposure but also lengthens the lifespan of the timber.

In conclusion, it’s viable to safely use preserved wood in garden beds when you take the proper precautions, while being mindful of the particulars involved and opting for suitable materials for your specific purpose.

Why Does Pressure Treated Lumber Warp?

Pressure treated lumber is prone to warping due to varied reasons such as variances in moisture levels, incorrect storage, and suboptimal installation.

Treating the wood can augment its ability to contract and expand; however, if it’s exposed to inconsistent humidity (i.e., too wet or too dry), it will likely warp.

Poor storage practices – like sitting the wood under the sun or on uneven surfaces – can also cause bending. Moreover, overtightening screws or nails while setting up can lead to a similar outcome.

To protect your structure, keep it sheltered and store the boards on reliable planes. Furthermore, use galvanized fasteners when dealing with this type of wood and observe appropriate maintenance habits for long-lasting results.

Learn more about wood warping in my article 8 Simple Strategies on How to Prevent Wood from Warping

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