Protect Outdoor Untreated Lumber- Dos & Don’ts

Untreated wood deteriorates rapidly in outdoor settings and requires frequent replacement. The lifespan of wooden buildings and furnishings may be significantly increased, and their quality maintained with the proper care.

In this article, we’ll cover the best methods for treating untreated wood for outdoor use, including:

  • Cleaning and Sanding
  • Sealing and Staining
  • Pressure Treating

Can You Use Untreated Lumber Outside?

Wood that has not been treated may be used outdoors, but it must be maintained to last. Water, which may cause corrosion and deterioration over time, is the most significant hazard to untreated wood. Outdoor sealers, stains, and paints may protect the wood from dampness. To avoid sun damage, use UV-filtering colors.

The type of wood also affects its performance with sealers, with species like Redwood Cedar and White Oak Cypress performing better than Pine Alder Hemlock. 

Maintenance, sunshine, location, and climate affect the lifespan of non-pressure-treated timber constructions. Vegetable gardens may last less than decks, which need more robust materials (5 years vs. 40 years). Linseed/Tung oil, varnish, polyurethane, lacquer, and semi-transparent deck stains are weatherproof non-pressure-treated wood.

Cleaning and Sanding

Cleaning and sanding are crucial steps when preparing untreated wood for outdoor use. Wood that has yet to be treated before exposure to the weather may swiftly decay, becoming cracked, warped, and unfit for outdoor use.

Some woods are water resistant while others rot rapidly; these factors contribute to the wide range of durability seen among different types of wood. 

Certain timbers are treated with preservatives and insecticides to increase their longevity, while others are not. Decks, arbors, benches, paneling, shingles, and trim are some of the many outdoor applications for treated wood.

Treated Wood: Unleash its Power!

unleash the woods power

There are several advantages to using treated wood, such as resistance to decay, degradation, and insect infestation. Treated timber is cured under pressure in vast airtight chambers with liquid preservatives, and high-quality producers often provide warranties against rot and decay for their goods.

However, special care must be taken while working with treated wood. Arsenic-laced chemicals were formerly used to cure wood, but that practice was halted in 2003 for residential usage. 

Even though modern treated wood is less hazardous, it still requires special care while handling and disposal. Sawdust made from treated timber shouldn’t be burned, and safety goggles should be used whenever the wood is shaped or cut.

Cleaning and sanding the surface of untreated wood is the first stage in the treatment process. The wood may be washed using a stiff-bristled brush and a mixture of warm water and mild detergent; afterward, it should be rinsed well and allowed to dry. 

Once the wood is dry, you may smooth rough patches with fine-grit sandpaper so the treatment can penetrate more deeply.

Sealing and Staining

Choosing and applying the right stain and sealant for your outdoor wood can protect it from moisture, UV radiation, and environmental factors and add style and personality to your wood deck. 

Follow the manufacturer’s recommendations and apply the product evenly with a brush or roller in thin layers for the best results.

Brush-on preservatives and insecticides may preserve outdoor wood. Choose a finish based on the wood type and durability. Stain opacity affects deck protection and aesthetics. Redwood, cedar, teak, and treated timber need different protection. 

Consider money, simplicity of use, skill, drying time, environmental effect, and health risks when selecting a finish. Depending on foot activity and sun exposure, stain your deck every three years. 

For a hand-rubbed finish, use linseed or Tung oil, apply polyurethane, varnish, or lacquer, or use a stain-sealant combination.

Water-based stains are more durable, but oil-based ones are still better. Oil-based stains need more frequent reapplication. For environmentalists, water-based stains are better.

To preserve the stain, use polyurethane when it dries. Consider money, simplicity of use, skill, drying time, environmental effect, and health dangers when choosing a finish.

Products for Exterior Wood Protection and Beautification

treated and untreated wood

Thompson’s WaterSeal Transparent Wood Sealer: a clear waterproofing sealer designed to protect exterior wood from moisture, UV damage, and other environmental factors that can cause deterioration.

Deck Premium Semi-Transparent Stain: a semi-transparent wood stain that helps protect and beautify exterior wood decks and fences. The semi-transparent formula allows the natural wood grain to show through while adding a subtle tint of color.

Defy Extreme Semi-Transparent Wood Stain: a Durable, water-resistant, semi-transparent stain designed to protect exterior wood from harsh weather conditions, including UV radiation and moisture.

Seal-Once Marine Premium Wood Sealer: a waterproof sealer specifically designed for marine environments, such as docks, boats, and other wooden structures exposed to salt water and high humidity.

Cabot Semi-Solid Deck & Siding Stain:  a semi-solid wood stain that provides protection and color to exterior wood siding and decks. The semi-solid formula offers greater coverage than semi-transparent stains, allowing some natural wood grain to show.

Ready Seal Wood Stain and Sealer:  a two-in-one product that stains and seals exterior wood. The product is designed to provide long-lasting protection from moisture, UV damage, and other environmental factors.

Thompson’s WaterSeal Penetrating Timber Oil: a penetrating oil designed to nourish and protect exterior wood from moisture and UV damage. The oil provides a rich, natural-looking finish that helps extend the life of the wood.

Protect Your Outdoors: Pressure Treating

Pressure treatment protects unprotected wood against deterioration and insects. The process comprises high-pressure preservation treatment of wood in a confined container. This lets preservatives permeate deeply into the wood, protecting decks, fences, and play sets for years.

Each pressure-treated wood variety has its own traits. Alkaline copper quaternary (ACQ), copper azole (CA), and micronized CA are typical wood treatments (MCA). Outdoor buildings may employ treated wood because it resists rot, decay, and insects.

New fences often use pressure-treated poles. These weather-resistant posts are suitable for harsh climates. For optimal results, follow the recommended guidelines when inserting pressure-treated fence posts.

To sum up, pressure treating is a fantastic choice for individuals who want to preserve their outside wooden buildings. Pressure-treated wood may prolong the life of a deck, fence, or play set.


If you have untreated wood in your backyard or even a wooden slide, now is the time to take action. By cleaning and sanding the surface of the wood, you are preparing it for outdoor use. 

Treated wood offers many advantages, such as resistance to decay and insects. However, treated wood must be handled with care due to the chemicals used in its treatment process. 

Sealing and staining can protect outdoor wood from moisture, UV radiation, and environmental factors while adding style to your deck or fence. 

Pressure-treating wood protects it against rot, decay, and insects, making it ideal for fences that experience harsh climates. For more information on how to treat your outdoor wood, let me know. I would love to help you get started on protecting your investment.

Happy treating!

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