Pressure-Treated vs. Cedar Lumber

For many Calgary residents, nothing beats the traditional appeal of wood for fencing and deck projects. As well to its attractive appearance, it’s affordable, versatile, sturdy, lasting many years.

But your decisions don’t end there if you’ve opted for a wooden fence. You’ll need to select between pressure-treated lumber and cedar as both are commonly used for fences and decks in the Calgary area.

These types of lumber don’t just look different. They also have many properties that might affect your decision —their advantages and disadvantages.

To help you familiarize yourself with the differences between pressure-treated and cedar lumber, we compare the materials below…

Pressure-treated wood is softwood lumber (usually plentiful woods like pine, spruce and fir) treated with preservatives to make it more durable for Calgary’s harsh climate.

Pine and fir trees grow quickly and have cell structures well-suited to pressure treatment. During the pressure treatment process, the wood is made harder and more durable using a simple, environmentally friendly procedure.

Lumber refineries dry the wood in a kiln, bundle it together, and place it in a huge pressure tank filled with wood preservatives. The wood is put under immense pressure, forcing the preservative into it. The most common preservatives are a mix of water and micronized copper and are usually termed CCA or ACA.

Pressure-treated wood is a popular choice for fencing and decking in Calgary because it has many advantages over other materials.

Advantages of pressure-treated wood

• Affordability: pressure-treated wood is lower in price (up to 35 percent cheaper) than cedar.

• Durability: well-maintained pressure-treated fences and decks will last 10 to 20 years or more.
• Availability: pressure-treated wood is freely available in Calgary DIY stores, including fence panels, deck boards and dimensional lumber.

• Insect resistance: the copper-based preservatives used in the pressure treatment process ensure that no bugs attack your fence or deck.

• Toughness: pressure-treated lumber is harder than cedar lumber and will resist wear and tear over time if you look after it.

Disadvantages of pressure-treated wood

Pressure-treated lumber is not perfect. Some people point towards the following disadvantages with it:

• High maintenance: you need to maintain a pressure-treated lumber deck or fence to keep it in good condition. It takes time and money to regularly apply wood stains.
• Hazardous: pressure-treated lumber contains ammonia and copper compounds, meaning you should wear gloves, a mask, and protective eyewear when working with it.

Corrosive: because of the preservative in pressure-treated wood, flashing will cause it to corrode. Specific green or brown coated deck screws are necessary because galvanized or zinc-coated screws will corrode.

Cedar is a naturally beautiful wood with a distinctive colour and a straight, evenly spaced grain pattern that makes it instantly recognizable. It needs no pressure treatment to increase its resistance to insects, cracking or splitting.

Western red cedar is by far the most common type used in Alberta, and it is a popular choice for fencing and decking in homes and commercial properties. The wood has a muted red tone, whereas the white cedar found further east is paler in colour (and less decay-resistant and insect-resistant).

Western red cedar lumber has significant advantages over other fencing and decking materials used in the Calgary area…

Advantages of cedar wood

• Naturally decay/rot-resistant: the acids (phenols) and oils within the cedar tree make it naturally rot/decay-resistant, even when exposed to moisture.
• Warp/split-resistant: Its low density and straight grain pattern won’t warp in moist environments, and its malleability helps resist cracking and splitting.
• Temperature-resistant: its low density also means it performs well in cold and hot environments as it can expand and contract without splitting.
• Insect-resistant: the acids in the wood deter insects as well as rot.
• Low maintenance: cedar remains in good condition for years with minimal maintenance, only requiring an annual clean with soap and water.

Disadvantages of cedar wood

• Price: cedar takes longer to grow than pine and generally costs 25 and 35 percent more than pressure-treated lumber.
• It fades: the initial red hue of western red cedar fades over time to a silver-grey, which is generally considered less attractive by homeowners.
• It’s a soft wood: its low density has benefits, but it makes cedar a relatively soft wood making it prone to unsightly dents and dings, especially when used for decking.

Pressure-treated and cedar lumber are both used extensively in outdoor settings in Calgary. It’s important to understand the key differences if you consider these types of wood for a fence or deck…

Appearance

• Cedar has a distinctive straight, even, and narrow grain with a russet, reddish or pinkish colour that fades over time to a silvery grey.
• Pressure-treated lumber has a wider grain, with a copper hue that ages to a dull grey.

Decay/Rot-Resistance

• Cedar is naturally resistant to rot and decay, and its low density allows it to flex and resist cracking. It lasts longer in wet weather.
• Pressure-treated wood needs regular maintenance to last, as it is prone to cracking and splitting (allowing moisture to penetrate).

Hardness/Strength

• Cedar is less dense and therefore softer than treated lumber. This makes it flexible and easy to cut and manipulate. Despite this, it is stronger, less so than pine and fir.
• Pressure-treated lumber is denser than cedar, so less prone to dings and dents on its surface (especially important to consider for decking).

Durability

• Cedar is extremely durable because it easily expands and contracts with the conditions and is more malleable than pressure-treated lumber.
• Pressure-treated wood is more prone to splitting and cracking, so stains or paint must be used to prevent water from penetrating the wood and causing rot or decay.

Odour

• The characteristic odour of cedar comes from the phenols it contains., which also make it rot/decay-resistant. The odour is most pungent in high-quality cedar.
• Any odour from pressure-treated lumber comes from the chemical treatment and wears off quickly after installation outdoors.

Affordability

• A piece of cedar that costs $20 would cost around $14 for a similar size piece of treated lumber, which usually works out around 30 percent cheaper (prices subject to flux of course!)

Availability

• Cedar boards for fences and decking are readily available throughout Calgary, as is pressure-treated lumber. Availability should not be a major issue.

Maintenance

• • Cedar requires only annual cleaning, while a sealer may be recommended to help it last.

Longevity

• A cedar deck cleaned annually should last at least 20 years without any rot or decay issues. If water penetrates cracks from wear and tear, slow decay may occur.
• Treated lumber is more susceptible to weather damage, so you can expect it to last a decade before the splitting and cracking problems start.

Installation

• Installation of cedar is simple with no special handling protection and standard deck fasteners for exterior use.
• Because of exposure to potential toxins, pressure-treated wood requires gloves, a mask, and eye protection when cutting. Cut ends should be treated so they don’t rot. Special, vinyl-coated screws that don’t corrode from the preservative must also be used.

Environment

• Cedar is environmentally friendly as long as the lumber is sourced from a sustainably managed forest.
• Pressure-treated wood cannot be burnt and should be taken to a treated wood disposal site when disposing of it.

Ultimately, if you compare a 20-year-old pressure-treated lumber fence or deck and a 20-year-old cedar one, the cedar will look more appealing because it does not easily warp, shrink, or split like pressure-treated lumber can with age.

While cedar requires less maintenance, you can extend the life of pressure-treated lumber and cedar fences and decks with regular maintenance.

So, your decision will usually depend upon your expectations for the fence or deck and how much work you are prepared to put into keeping it looking good.

If you have the budget, cedar is usually the better choice for Calgary’s cold winters and wet summers, which can be a stringent test for any outdoor wooden installation.

If you want your fence or deck installed the right way, the Relia-Built team is here to serve you. We will project manage the installation from initial advice and quote to the completed build and clear-up.

Remember, our estimates are FREE and always will be.