Treated Or Untreated Wood For Shed – Which To Choose?

A shed is a practical small building to have on your property for storing gardening tools and other miscellaneous items. However, if you will build a shed as a DIY project or are shopping around, which type of wood works best? We researched what experts had to say about using treated or untreated wood to build a shed and their recommendations. Don't feel stumped about how your choice of wood impacts the longevity and performance of your shed; read on to learn more.

Most experts feel it is optimal to choose treated wood for constructing a shed. However, if you choose to use untreated wood, be prepared to coat it with UV and weather-resistant products to protect it from the elements.

Treated wood is better for a shed because the structure will be it exist outdoors. The type of wood used for a shed is critical because it will be in constant contact with precipitation, extreme temperatures, and it must protect the contents inside.

Discover how to create a durable, reliable shed using wood to store mowers, hedge clippers, rakes, and other necessary tools for your property.

An up close photo of untreaded wood, Treated Or Untreated Wood For Shed - Which To Choose?

What Wood Works Best For A Shed

Maximize your storage capacity with an attractive and well-made shed from wood. Although sheds available for sale may be made from vinyl, metal, or resin, wood is a desirable choice for its durability and versatility. Use a wooden shed to stow away yard tools, holiday decorations, and items you don't want in the garage or attic.

Wood is a popular material for sheds because it is easy to create a custom-sized structure. It is a good insulator, adding aesthetic value to a property. Be mindful of getting acquainted with the pros and cons of choosing treated or untreated wood for your shed.

A bright yellow colored shed with white painted window and door frames

Here are some points to keep in mind.

  • OSB takes a while to get wet, takes longer to dry than plywood, and needs to be sealed after installation. It is good for exterior walls.
  • Plywood is a mid-grade choice that performs better than OSB, but it also needs to be painted, sealed, or covered. Look for plywood stamped with an X because it doesn't require staining, painting and is suitable for exterior walls.
  • Cedar and redwood are exceptional choices for an outdoor shed because they naturally resist pests, rot, and tolerate moisture and extreme temperatures over the years. They are both great to work with and create durable, attractive structures.

Before committing to a specific type of wood, understand how it will perform under certain conditions, any desirable qualities, and your budget.

Treated Wood

It is ideal to choose pressure-treated lumber to construct a shed, especially for areas that will routinely come in contact with the ground, moisture, or pests. A shed that is out in the open and exposed to the elements should be pressure treated, including the structure's framing.

Framing lumber or pressure-treated wood is best for the shed framing, floors, and exterior walls. Choose woods like redwood, cedar, or oak, and select lumber for qualities like rot-resistance and visually pleasing qualities. Note that framing lumber is often fir or spruce, and it is good for the walls and roof.

The exterior walls can be OSB, which is more inexpensive than plywood but not as durable. OSB or Oriented Strand Board is an engineered wood made from glued pieces of soft woods, similar to particleboard. Choose OSB planks that are tongue and groove for a shed floor with a thickness of 20 millimeters.

CDX plywood that is pressure treated and has a thickness of 3/4 inch is good for shed floors. The floor is liable to encounter dampness, so pressure-treated wood is best for increased durability and reduces the chance of the floor readily sagging or rotting.

Both OSB and CDX plywood can be used to construct a shed roof, but the most optimal wood is cedar. OSB is typically a bargain-budget option and should have a minimum thickness of 9 millimeters. CDX at 15/32 with a thickness of around 3/8 of an inch work too.

Make your shed more secure and apply waterproof paint, sealant, caulk gaps, and utilize wood shingles. You can also add a protective, insulating layer of metal or fiberglass to the underside of a wooden roof.


  • Greater longevity
  • Resistant to the elements, rot
  • Durable and low-maintenance construction materials


  • May be exposed to chemicals when cutting wood

Check out this handy wood shed kit on Amazon.

Untreated Wood

Some people like to use untreated wood to build their sheds because they can add their choice of a water-repelling sealant or protective coat later on. Untreated wood is typically less expensive than wood treated with chemicals or additives to increase its durability and resistance against the elements.

To preserve the life of a shed, it will need to be waterproofed with an approved oil, stain, sealant, lacquer, or finish. Untreated wood can suffer damage from fungi, insects, weather, and rot in a short amount of time.


  • Less expensive than using treated wood
  • No threat of harmful chemical exposure when handling or augmenting


  • If used for flooring close to the ground may incur rot
  • May develop damage if left untreated after prolonged sun exposure or precipitation contact
  • Requires additional sealant or another treatment to prevent decay and damage

Check out this wood sealer on Amazon.

What Is The Best Plywood For A Shed?

The most economical and reliable type of plywood to use for constructing a shed is CDX. Lighter-weight sheds should be outfitted with plywood that is at least 1/2 inch thick.  Choose CDX plywood for both exterior walls and the roof of a shed, and use it for flooring.

Before committing, look over the grade and quality of plywood, as not all are suitable for a longstanding structure outside or are weather-resistant.

Read More: Is Plywood Waterproof? [Complete Plywood Waterproofing Guide]

How Thick Should Plywood Be For A Shed?

Choose the right thickness for plywood, depending on whether it is used for the walls, floor, or roof of a shed. A thickness of 1/2 an inch is best for the roof and wall sheathing. Plywood for flooring should be a minimum of 5/8 inches thick. If a shed has wall studs that are 16 inches apart, you can use plywood that is 3/8 inch thick. If the studs are 24 inches apart, opt for plywood that is 1/2 an inch.

Can I Use OSB For Shed Walls?

OSB is usually available, sized 4 x 8 feet. You can use OSB for shed walls, but they will need to be sealed or covered to prevent moisture exposure and rot. Depending on your shed's dimensions, the OSB should be between 12 to 15 millimeters thick. Consider using OSB that is 7/16 inches thick for the walls of a shed measuring 9 x 11 feet.

Should I Use 2x4 Or 2x6 For Shed Floor Joists?

Plan to use 2x4 for a small shed in size and doesn't span wider than 5 feet. Ideally, it is better to use 2x6s for shed floor joists. Choosing 2x6s is budget-friendly and the more common option when creating a floor for its ability to bear a significant weight load and offers flexibility with construction. A shed measuring 10 to 12 feet in width works best using 2x6s and opt for No. 1 grade lumber.

In Closing

We hope you feel more knowledgeable about the best wood choices for building a shed. Create a classic shed from wood that you'll be proud to have in your backyard and store essential items. Wood is a suitable construction material for sheds because many types of wood naturally resist insects, rot, and have insulating properties.

Before you go, check out the following informative articles:

What Is The Difference Between A Hip Roof And A Gable Roof?

What Nails Should I Use For Wood Siding?

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