Does Wood Or Exterior Grade Lumber Need To Be Treated?

Non-pressure treated wood can be used outside, but it requires protective measures to ensure its longevity. Outdoor wood sealers, stains, and paints can be used to protect untreated wood from moisture, mold, and insects. Pressure-treated wood is suitable for projects where wood encounters moisture above or below ground, such as decking or fence posts. Treatment helps prevent water damage, mold, and insects.

For wood in contact with or partly buried in soil and not adjacent to food plants, pressure-treated wood should be used. If it’s above grade and will dry out, pressure-treated wood should be used. The International Building Code requires this treatment.

There are two types of exterior wood treatments: those that absorb into the surface of the wood, such as oil-based products, and those that form a protective coating on the wood. If you choose to finish pressure-treated lumber, it is not impossible to do so. However, it is important to consider the type of wood and the type of surface treatment needed.

Pressure-treated wood is resistant to rot and critters and should be treated every 12-18 months. This is the best way to keep furniture and fixtures looking their best. The chemical preservative used in the process makes lumber resistant to insects and moisture, and can even protect the wood in severe weather.

Outdoor plywood is treated to withstand the elements, making it highly durable and resistant to moisture, rot, and decay. However, poly is not a good choice due to low UV protection and not well suited for outdoor settings. Dry wood is more stable, but it may become wet from humidity outside and expand, cracking. Pressure-treated lumber contains arsenic to prevent rot and bugs from eating it. Marine grade plywood does not have voids, and exterior panels use glue that can withstand repeated wetting and redrying or long-term exposure to moisture or high humidity.

How is exterior wood treated?

Wood oils are a durable and waterproofing finish that prevent drying, warping, and splitting. They can be applied in thin, even coats, allowing each to absorb and dry before re-applying. They are suitable for decking and garden furniture, and come in shades and finishes for both softwoods and hardwoods. Wood stain and dyes are also used to protect exterior wood from weathering and heavy foot traffic, adding rich color and long-lasting durability.

They enhance the natural wood grain, providing a hardwearing, scuff-resistant finish. Wood stains come in various colors, including wax-enriched formulas for enhanced water repellence and a non-slip finish, making them ideal for decking.

Can you build with untreated lumber?

Building frequently interacting items like playground equipment, lawn furniture, or benches should use untreated wood. This type of lumber is safer and more affordable than treated lumber, as it is free of harmful chemicals and requires no protective gear. However, it lacks the chemical protection against decay and pests that treated lumber provides.

Choosing the right materials is crucial when building wood projects, especially for playgrounds or garden beds. Many forms of treated lumber can be harmful to health, as they were filled with dangerous chemicals and compounds like creosote, pentachlorophenol (PCP), and chromated copper arsenate (CCA). These chemicals and compounds are not safe, and the arsenate in CCA is a form of arsenic, a carcinogen known to cause various types of cancer and even death. Therefore, it is essential to choose the right materials for your project.

Do I need treated timber for outside?

Treated timber is a type of timber that has been modified with preservatives to protect its exterior and allow it to be used outdoors. It is suitable for general construction, fencing, garden, and leisure timber applications, as it resists water and insect infestations. Untreated timber can cause damage to decking, fencing, and outer walls. Fire-treated timber, which has a fire retardant applied, is an alternative product.

While hardwood timbers can be used outdoors untreated, softwood timber without treatment is likely to experience severe rot problems. Pressure-treated timber is another option for general construction, fencing, and garden and leisure timber applications.

Is it okay to leave lumber outside?

Dry lumber should be stored in a dry, dry location, either off the floor with skids or on shelves without roof leaks. Avoid storing it outdoors due to water and temperature changes. However, green lumber can be stored outside with stickers between each course to help it dry. Some woodworkers use a lean to to keep rain and snow off the lumber, increasing its drying rate. Stored in your shop for a week before machining ensures the lumber remains top quality and prevents movement after cutting. This will help maintain the quality of your lumber.

Can I use untreated timber outside if I paint it?

If your outdoor wood is untreated, it’s crucial to treat it immediately to prevent rot, fungi, and weathering. Use a wood preservative, either a wax-enriched preservative or a wax-free preserver, for an all-round coating. If the wood is dip-treated or paint-stained, it may fade after 6-12 months and provide less protection against the weather. Treat this with a wood stain, paint, or preserver. You can treat un-treated or dip-treated wood at any time.

What happens to untreated timber outside?

Untreated timber, which is left in its natural state, is susceptible to various environmental factors such as weathering, fungal decay, and insect visitors. Sun exposure and moisture can deplete the natural oils in the wood, leaving it dry, discoloured, and disfigured. When choosing timber for projects, it is crucial to consider its treatment, as it will determine factors like life-span and potential applications. Untreated timber is ideal for interior projects where it is safe from weathering, but for other projects, it could be a poor and potentially dangerous choice.

This guide page aims to discuss the benefits and potential negatives of working with untreated timber and provides information on the process and FAQs. If you’re considering treated timber for your project, check out the What is Treated Timber guide page for more information.

Does exterior wood need to be treated?

Building codes dictate where treated wood can be used, typically in areas with moisture risk. Outdoor wood should be pressure-treated, while interior design wood like cabinetry or furniture doesn’t require the same level of treatment. The AWPA states that the type of wood treatment depends on its usage, and extra steps are needed to finish pressure-treated wood in indoor or outdoor projects that may come into contact with humans or pets.

The chemicals in pressure-treated lumber are pesticides, so handling them with the same precautions as any potentially hazardous material is crucial. Wearing gloves and face protection is recommended, as sawdust from cutting the wood can be irritant.

Can you use untreated lumber for a deck?

It is not advisable to utilise untreated, non-durable wood, such as pine, for the construction of decks in the context of the warm, humid climate that is characteristic of Tennessee. This is due to the fact that such wood is prone to rapid deterioration, which may not offset the financial savings that can be made in comparison to the relatively short lifespan that it possesses in certain geographical regions.

Can all wood be used outside?

Before starting an outdoor project, consider the wood type, its exposure to elements, its natural resistance to rot and insects, and the best treatment method. Most woods are resistant to rotting, while moderately resistant woods include Douglas fir, larch, sapele, and meranti. Hardwoods require more upkeep due to weathering and fading, which can cause discoloration, surface cracks, and warping. A UV-blocking finish or topcoat can protect them from fading. Opting for a hardwood that is resistant to deterioration, such as thick or oily wood, can lower the chances of fungus infection.

Outdoor finishes for hardwoods should be UV-protective and waterproof. For outdoor projects like building a deck, trees from the Far East, like Balau, can be used without treatment. These woods have exceptional resistance to decay and can last for many years if not kept too wet and away from the ground.

In summary, selecting the right wood type for an outdoor project requires careful consideration of exposure, resistance to rot and insects, and future upkeep.

Does outdoor lumber need to be treated?

The choice of wood for home improvement projects significantly impacts the final outcome. Treated lumber is ideal for outdoor use, as it can withstand harsh weather conditions. Understanding the differences between treated and untreated wood is crucial for making the right choice. The manufacturing process is the main difference between the two types of wood. Benefits of treated wood include increased durability, reduced maintenance costs, and improved aesthetic appeal. Cost factors also play a role in the decision.

What wood does not need to be treated?

The following table presents a comparative analysis of five wood alternatives, including redwood, cedar, juniper, bald cypress, Pacific yew, chestnut, black locust, osage orange, and black walnut. Each alternative is discussed in terms of its inherent advantages and disadvantages.