GemThane offers a family of polymer-coated wood products that combine outstanding longevity with the warmth, charm, and value-enhancing properties that only real wood can create.

The appeal of pre-finished wood siding can be compelling, but only if the brand you choose can deliver the quality and longevity you seek. In this section of the website, we’ll tell you exactly how GemThane is uniquely able to meet your expectations.

When it comes to pre-finished wood decking, GemThane is in a class by itself (ours is the only low-maintenance real wood product on the decking market) because of the same technology that has made GemThane siding the leader in its market segment.


Whether it’s siding or decking, we use cabinet grade wood and our lumber mills kiln dry it to cabinet grade standards. Then we apply multiple layers of polymer coatings specially developed for siding and decking applications under virtually any climatic condition.


Surprisingly Economical

As you learn more about the quality built into GemThane siding, you may ask yourself “This sounds fantastic, but is it affordable?” The answer, we are happy to say, is yes. Briefly, GemThane siding costs more to purchase but is less costly to install. For more information, read the GemThane value proposition.


Our polymer technology

Our parent company, Madison Chemical, has been inventing and marketing polymer coatings for the infrastructure since 1973, usually for critical applications where the service life is measured in decades. When Madison’s GemThane Division decided to make pre-finished wood siding back in 2005, we took the same long-term approach. Based on well-established coating formulations, we developed a tough five-layer cladding that is sprayed on to the wood at high pressure. Other brands of pre-finished siding are merely flood coated with one or, at most, two coats of ordinary latex paint or stain.

Put simply, the main difference between a polymer coating and a paint is that polymer coatings cure by a chemical reaction, whereas paints and stains merely dry through evaporation. At a glance, both products look similar, but the performance difference is remarkable. You can prove it for yourself by taking the GemThane Challenge (see sidebar article on the left side of this page to find out how you can check out the difference for yourself).

Making wood waterproof while still allowing it to breathe was a challenge that our product development team took in stride. Our polymer coatings are classed as “semi-permeable membranes” and so they work just like sports fabrics. This means that they keep liquid water out, while allowing water vapour to pass through. Thus the wood is cocooned from its environment without being smothered. No other product can offer this feature, which is a huge benefit in harsh climates.

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Take the challenge!

Order a "GemThane Challenge" test kit, which consists of a sample of GemThane siding and a competitors' siding product. Toss them both into a bucket of water, and let them sit there for a week.

At the end of the week, you'll likely see deterioration already taking its toll on our competitors' product, while GemThane will still look new!

Contact GemThane to take the challenge!


Unique Additives For Even Better Performance

Having the right polymer ‘backbone’ in a coating is only half the battle.
The additives we use are as unique and robust as the coatings themselves. These include:

MicroSpear, a permanent anti-microbial additive that is non-leaching, food grade and able to last for the life of the coating system. MicroSpear prevents mold and mildew from attacking the substrate.

NanoShield, which consists of microscopic spheres of real ceramic. Just like the finishes on luxury automobiles, we use NanoShield to increase the resistance of our coating systems to impact, chipping, and abrasion.

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UV stabilizers. We use the same UV stabilizers that are used in marine and auto finishes, except we use a higher loading. Why? Because your siding and decking are subjected to more UV exposure than your automobile.

Pigments: we use automotive and industrial grade pigments that stand up much better then the pigments used in consumer-grade paints and stains.

The wood we use

Using the world’s best coatings makes sense
only if the substrate is also the best.

Several species of wood are used to make wood siding. Most other brands use lodge pole pine, black spruce or white spruce. We prefer Eastern White Pine, often called “The King of Softwoods” because it comes from far larger trees and is inherently more stable. Eastern White is used predominantly by door, furniture, cabinet and window manufacturers for that very reason. We even use the same grade they use.

Our mills then slowly kiln dry the wood over a three week period to furniture grade specifications (less than 10% moisture), in humidity controlled kilns. This controls the drop in moisture content so that the internal stresses in the wood are relieved during the drying process and the wood becomes more stable. Toward the end of the drying process, the temperature peaks at more than 70°C (160°F) in order to “set the pitch”; this minimizes knot discolouration and bleedthrough. That temperature spike also sterilizes the wood so that, when we apply our anti-microbial coatings on all sides, the wood is truly protected from both internal and external sources of mold, mildew, and bacteria.

All of our suppliers practice sustainable forestry and are FSC or PEFC certified.

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Putting it all together: the products we offer

Value Plus Siding

On our Value Plus siding, the five-layer polymer coating on the face of the boards starts with ArborSeal, a clear coating with an extra-heavy dose of MicroSpear in order to inhibit bacterial attack. We put extra on the knots for good measure. This is followed by four coats of an acrylic-based resin called GemThane AquaTech. AquaTech’s industrial-grade rating means that it will outperform, by a wide margin, any paint-based product on the market. On the back side, we apply two mils of ArborSeal.

Performance Plus Siding

On our Performance Plus line of siding, the coating that we use (called Cottage Coat) is even tougher. Cottage Coat’s marine grade rating means that this polyurethane-based product is suitable for immersion service. It would be quite happy protecting the hull of your boat, so protecting your wood siding is an easy task for Cottage Coat. Again we start with ArborSeal, followed by four separate coats of Cottage Coat. On the reverse side, our Performance Plus siding is protected with a triple thick layer (six mils) of ArborSeal.

Dex-N-Dox deck boards

Because of its marine rating, we also use Cottage Coat as the protective barrier on our Dex-N-Dox product. Decks are frequently subjected to ponding water and are typically snow-covered for much of the winter; Cottage Coat is ideal for these near-immersion conditions. The Dex-N-Dox process also involves five layers but involves some extra steps in order to give a finish that is textured but feels smooth underfoot.

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Our coatings don’t absorb dirt, so they are a breeze to clean. You can even power wash our Performance Plus siding and our Dex-N-Dox deck boards.

Annual touch-up is also fast and easy. All you do is apply a touch-up material (which we supply) to any areas where the wood has been exposed by virtue of physical damage or unavoidable natural causes such as wood movement.

Special requests can be accommodated. For example, if you want cedar for your siding or decking, we’ll work with your local lumber supply dealer. They will supply the wood and we’ll simply charge a processing fee. The same applies for unusual trim items, garage doors and other items. The result is a customized result at a very reasonable cost.

Invented in Canada For Harsh Climates

GemThane wood products were developed with demanding climatic conditions in mind. Ordinary paints and stains claim to be “breathable” but they are actually quite porous. Immerse a sample of any competitive product for a few days and you’ll see that they soak up water like a sponge. That’s a huge problem because this allows freeze-thaw cycles between October and March to wreak havoc with the underlying wood, even if the paint itself still looks intact. By contrast, our polymer coatings laugh at the elements, from the subzero temperatures of high prairie winters to the piercing glare of reflected sun on a hot lakeside summer day.

Learn more about our siding and decking products.

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