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The Advantages and Drawbacks of Pressure Treated Catios

First, what is pressure treated lumber?

Pressure-treated lumber, or PT wood, is lumber like Southern pine, spruce or fur that has undergone a chemical process. The process helps this lumber stand up against rot, decay, and insect infestation.

Is pressure treated wood toxic?

Pressure-treated wood has a notoriously bad reputation because many people are familiar with CCA lumber used in children’s playsets and decks that contained arsenic. However, in December 2003, the United States Environmental Protection Agency (EPA) discontinued the use of lumber preserved with Chromated Copper Arsenates (CCA). The EPA has now restricted to the use of CCA lumber in residential settings.

Since this regulation, there have been a number of developments in newer wood preservatives for residential use. Alkaline copper quaternary (ACQ) is by far the most popular of these alternatives and is a water-based preservative. This type of wood preservative is the one often found in pressure-treated wood today.

Unlike CCA, ACQ lumber is approved by the EPA for use in residential settings, and even in freshwater and marine water settings. According to a research study from the University of Guelph’s Center of Toxicology, chemicals associated with the surface of this type of wood are not harmful to children or adults.

When used in residential settings today, this wood type can be durable, and resistant, but also has certain limits. We will explore the benefits and the shortcomings of using this wood for a cat enclosure.

The Best Pressure Treated Catio We Recommend for Your Cats

  • 12ft x 12ft
  • Freestanding 
  • Painted/Sealed
  • Raised Floating Deck with 1 foot cantilever skirt
  • Enclosed Roofing
  • Polycarbonate Roof
  • Double Screening (critter fence black steel square grid 1×1 and high quality bug screen)

What are the advantages of pressure treated catios?


Durability means the wood’s ability to withstand elemental and natural forces of decay. Wood being an organic good is susceptible to this natural process. Different types of decay include:

· Wet rot and dry rot (fungi)

· Insects

· Parasites

When pressure-treated lumber undergoes the chemical process of pressurization and vacuuming, the preservatives are embedded into the cellular structure of the lumber. As a result, a pressure treated catio can withstand fungi and rot as long as maintenance is upheld.


Compared to other wood types such as cedar and redwood, pressure-treated lumber is economical. Because it can last for decades and is more cost-friendly than other wood choices, pressure-treated lumber tends to be the most economical in the long run. Manufacturers aim to keep the price of this wood lower which makes this a great wood choice for lower budgets.

cat topia catio
Inside Pressure Treated Cat Enclosure

2-Resistance to Insects:

Consequently, a pressure treated catio is highly resistant to insects, and pests. Pressure treated wood will be effective in protecting against:

· Termites

· Beetles

· Carpenter’s ants

Both termites and beetles like to feed on wood whereas carpenter ant’s like to make their nests in wood. Needless to say, the chemicals used in pressure-treated wood will make this wood resistant from pests, and insects.


This timber is extremely versatile for the following reasons:

  • Smoothness: which allows for a flawless finish when painting.
  • Versatility in finish: This wood can be easily stained, painted, or sealed depending on your preference.
  • Fire-retardant: If interested, one can purchase pressure-treated wood with chemicals that help protect against fires.
  • Variety of sizes: 2X4, 2X6, 2X10… When choosing a pressure-treated catio, there should be no problem in finding a variety of sizes of this wood.

What are the disadvantages of pressure treated catios?


Although pressure-treated wood can resist easily to insects, and rot, it does not come without maintenance. It is recommended when working with pressure-treated wood to seal your wood. If the pressure-treated wood is exposed to the elements constantly this step ensures that it will be protected from any water distorting the wood.

We recommended to annually deep clean your pressure-treated wood catio to keep it looking its best. This is often done in the spring or early summer. After a deep cleaning, you can seal, re-paint, or re-stain the pressure-treated wood if you desire.

If you are working with painted wood, it is best to use a product that does not contain ammonia. There are many Eco-friendly products on the market that will ensure the safety of plants, animals, and people.

How to clean catio made with pressure-treated wood:
  1. Clean off debris with a broom or a brush.
  2. Use hose water or a bucket of hot water to the clear the surface completely of debris.
  3. Use a non-toxic wood cleaner adapted for your pressure-treated diluted in water.
  4. Spray the cleaner on the wood and let it set for 10 minutes.
  5. Scrub it using a broom, or mop going in the direction of the wood’s grain.
  6. Rinse thoroughly the wood.
custom outdoor catio build miami florida pressure treated

2-Not environmentally friendly:

Compared to other lumbers, pressure-treated wood is probably not the most eco-friendly choice. Although this lumber contains no arsenic, it still contains other chemicals such as copper and nonmetallic biocides. Though these chemicals pose no problems for humans, animals or plants when used in a residential setting, these chemicals can leach or drain away in the long-term. ACQ lumber leaches but is low in toxicity compared to CCA. More research needs to be done on the exact impact of small amounts of copper in the environment.

Some woods like redwood or cedar are examples of wood that are naturally durable and are not infused with chemicals that could potentially leach into the environment by landfills. These species of wood can be alternatives to pressure-treated wood in home projects and are considered to be renewable while also lasting for years like pressure-treated wood.

If you decide to buy pressure-treated lumber, look for the retention levels indicated on the tag. The labels for pressure-treated wood usually state “above ground,” “ground contact,” or “ground contact/freshwater use,” which correspond to progressively higher retention levels.

Below you can find the retention level information on ACQ.

Below you can find the retention level information on ACQ. For more information on retention levels, homeowners can refer to The American Wood Protection Association.


Like any wood type, pressure-treated wood can also give splinters. This can be avoided by sealing the wood when installed.  

When sealing a pressure treated catio:  

  • For a natural finish, apply a clear water repellent 
  • Apply within six weeks of completion and reapply annually  
  • Pick a sealant with UV stabilizers and water repellents 


Final Thoughts

Since 2003, pressure-treated lumbers such as ACQ cannot be considered a health hazard. Ultimately, this lumber is a good choice for cat owners who prefer a wood that is cost-effective while also durable and long lasting. This type of wood allows for many finishes such as paint, and staining. Conversely, if you’re looking for a wood that is more environmentally friendly, we would recommend choosing cedar or wood—lumbers which are “naturally durable”. Perhaps the biggest drawback in this wood type is the annual maintenance to keeping the catio looking its very best.