Skip to Content

How Long Does T1-11 Siding Last? (And How to Maintain It)

There is little doubt about the advantages of T1-11 siding. It is an attractive and functional siding material. It is also relatively inexpensive and easy to install. However, the durability of a siding is considered to be more important, and one of the main deciding factors when choosing a siding material is how long it will last.

T1-11 siding is a very durable siding material and can last for more than 20 years if it is properly installed, regularly maintained, sealed with quality paint or stain, and protected from water and mold damage.

Here is a popular stain that people use on this type of siding, found on Amazon.

Whether you’re planning to use T1-11 siding in your new shed, house, or wall, this article will provide you with information about the quality of T1-11 siding and discuss protection and maintenance tips to make it last longer and stay attractive.

House with T1-11 Siding

Is T1-11 Siding Treated?

T1-11 siding is not treated and is vulnerable to moisture damage. It comes in two types: plywood and OSB (oriented strand board). The OSB version of T1-11 is made with wood pieces and strands glued together and water-treated with binding resin. While it is strong, it does not have the same quality as plywood T1-11.

Because of the way it is manufactured, OSB is more susceptible to water and structural damage than plywood T1-11 siding. It has a high moisture absorption rate and will delaminate or buckle over time as the glue binding becomes less effective. When the siding buckles, it will start chipping and rotting.

Plywood siding is mostly made of cedar or fir and is more expensive than OSB because of its superiority in durability and functionality. It has a better variety of finishing options as it can be primed and painted or stained to produce a natural wood feel.

Some manufacturers also produce pressure-treated plywood siding. This type of plywood siding is injected with rosins and other chemicals, under pressure, to make it waterproof and protected against termites, rot, and fungal decay. It is the best version of T1-11 siding as it lasts considerably longer.

Both Plywood and OSB T1-11 siding should be treated or primed. Sealing T1-11 siding protects it from harsh weather and other elements. While it may lose its initial appeal and natural look, its life will be extended for several years.

Best Protection for T1-11 Siding

House with T1-11 Siding

As mentioned previously, the best protection that can be given to T1-11 siding is painting or staining it. For it to be effective, the sealing of T1-11 siding must be done before installation. Your choice of sealing depends on your resources. However, if you’re using OSB, the only option you have is to paint it because the wood strands will show through its surface when stained.

Using the right type of seal is also important. Choose a paint or stain product that is of good quality and complements your home’s wood and climate. To give your siding some amount of UV protection, use a semi-transparent paint or stain if you live in a hotter climate, and dark-colored if you’re in a colder region.

Apart from sealing and finishing, you should ensure that your siding is at least 8 inches above any soil to prevent damage from moisture and insects. Also, trim or cut any shrubbery, bushes, or tree branches within its reach. If woodpeckers are constantly visiting your siding, use a wind chime to keep them away.

Since T1-11 siding can be easily damaged by moisture, keep your indoor humidity level below 65%. If you live in areas prone to ice damming, you can prevent ice and snow damage by using roof heat tracing cables.

Related How Much Does Aluminum Siding Weigh?

How to Paint T1-11 Siding

Painting your siding is relatively easy and is the most recommended form of protection for T1-11 siding, as it can last for a very long time. Here’s how to paint T1-11 siding:

  1. Clean the wood: A pressure washer can be used to remove dirt on the wood. If you’ve painted it before, use a wire brush to scrape off old paint. Allow the siding to dry for at least 24 hours before proceeding.
  2. Change damaged panels: The edges of the siding panels are highly absorbent. If you find any loose panel, fasten or secure it. If it is damaged beyond repair, it’s best to replace it.
  3. Caulking: Before getting started with painting, it is recommended to seal the window and door edges with caulking. You should also re-caulk if the original caulking is dry-rotted or damaged.
  4. Prime the Siding Sheets: Giving your siding a coat of primer seals the grain and prevents the topcoat from soaking in. This gives the siding better protection and increases paint efficiency and adhesion. A good practice is to use a primer that’s tinted a few shades lighter than the paint or closely matches the color of the paint.
  5. Paint it: Apply two coats of paint to ensure a long-lasting finish. Consider using an airless sprayer or a roller to apply the paint. You may use an exterior acrylic paint or a more expensive elastomeric paint. Give the first coat enough time to dry before adding the second. For better results, paint in dry weather.
  6. Re-prime or re-paint: When the second coat of paint is dry, inspect the sidings for any parts or cracks you may have missed. Ensure you cover the whole siding with paint.

How to Maintain T1-11 Siding

T1-11 siding has several benefits, but just like every other wood product, it requires maintenance to keep it in good shape. You should inspect your siding at least once a year, or quarterly if you can. Regular inspection helps you to identify and quickly correct cracks, holes, chipped parts or paint, and cracked board.

If you use stain on your siding, you need to touch it up or apply a new coat every 3 to 5 years. A good paint job lasts longer than stain, and you may only have to re-paint every 7 to 10 years. However, re-painting can be more difficult than re-staining as you will need to strip, scrape, and sand off the old paint before applying a new one.

Cleaning also helps to prolong the life of T1-11 siding and should be included in your maintenance tasks. Cleaning removes dirt, which is the most common cause of grime and discoloration on wood siding. A garden hose or a power washer can help you get the job done when cleaning.

If you’re using a power washer, you need to set it to low pressure and keep a one-foot distance as the high force can damage the siding, strip the paint, or drive water through the painted surfaces. If mold is growing on the siding, spray a detergent solution containing oxygen bleach or mildewcide on the surface and scrub it off with a soft-bristled brush.


T1-11 siding is an attractive and durable siding material. When properly installed, sealed, and maintained, it can last for more than two decades. Since it is not treated, the best way to protect T1-11 siding is to paint or stain it. This helps to protect it from the elements and further extend its life for several years.

Here are other important tips to keep in mind to make T1-11 siding last long:

  • Inspect it annually or quarterly
  • Keep it at least 8 inches above any soil and ensure no tree branch or shrubbery is touching it.
  • Re-stain your siding every 3 to 5 years, or re-paint it after every 7 to 10 years.
  • Regularly clean its surfaces to remove dirt, mold, or grime. 

Thanks for reading!

For more, check out Is It Okay to Drill Into Vinyl Siding? (With an Alternative).

Main photo courtesy of Chris Lattuada.