Best Composite Decking for a Full Sun Deck and Two Runner Ups


A south-facing back door is a perfect place for a deck. A full sun deck that you can bask in the sun’s warmth all day long. With the maximum sun exposure for any deck. Such an ideal deck location requires durable, long-lasting decking. Meaning a composite or PVC will be your best choice for deckingOpens in a new tab.. But not just any composite deckingOpens in a new tab., the best decking location requires the best composite decking for full sun.

The best composite decking for a full sun deck is Fortress’s Apex, performing well in the sun’s heat, limiting fading and disintegration from high levels of sun exposure. Another advantage of Apex is it’s limited expansion and contraction from heat compared with other composite decking.  

Two other composite deckingsOpens in a new tab. that also perform well in the sun are TimberTech’s Azek and MositureShield’s Vision. Giving you a choice between at least three decking offerings for a full sun deck.

When considering composite decking for a full sun area, I have four top of mind categories.

  1. Decking boards that are cool to the touch
  2. Decking Colour that doesn’t fade with high levels of UV
  3. Material cap that doesn’t disintegrate from the sun’s rays
  4. Amount of Expansion and Contraction the deck boards

Going through these four categories, we can better understand which composite decking is best for full sun. Decking can be enjoyed even in the heat of the day, along with not breaking down or fading because of the high sun exposure level.

The most apparent and most obvious difference and often the deciding factor in decking is appearance. All three boards considered look distinctly different from each other. Giving your deck an entirely different appearance and feel depending on which decking you choose.

A deck, as with any home improvement, there is a level of aesthetics to be considered.  The colour and appearance of the decking. For your deck to be enjoyed it will need to look good. Which is highly subjective as a personal taste.

Meaning that one decking may be better for your deck strictly on how it looks in the sun. But knowing that all three here will perform well in the sun.

But for here, let’s focus on what to look for in decking installed in full sun. Comparing these leading composite decking boards concerning the sun and their performance.

Starting first with heat, the decking temperature.

All Decks Will Get Hot in the Sun

All decks with full sun exposure will get hot. The more sunlight, the hotter the deck and decking will get. Steps can be taken to reduce the deck’s temperature, but it will still get hot.

This is mostly to do with the science of heat and reflection. Decks are a flat surface reflecting the sun’s heat more than the cool grass in your yard. Making the deck hotter in the sun than anywhere else in your yard.

“Making the selection of decking so critical.”

Regardless of how hot the sun gets, you want decking that will not burn your feet.  

How the deck responds to the sun makes all the difference. How much heat the board absorbs and reflects. One a comforting warmth, the other a shocking burning sensation.

Composite Decking Boards That are Cool to the Touch

Traditionally composite decking is hot to the touch. Especially in direct sun. The plastic boards burning the skin, causing sudden recoil when touched in the sun.

That was back in the ’80s. Composite decking has come along way. Evolving to a much better product to be enjoyed in the sun. Three companies, in particular, have made great strides in making cooler deck boards. Composite decking that will not burn you in the sun.

Those three companies are MoistureShield, Timbertech Azek and Fortress. All with decking lines promising to be cooler in the sun.

MoistureShield has gone about it using CoolDeck® Technology. A patent product is part of three of the deck boards Cathedral Stone, Mochaccino, and Cold Brew. Slightly lighter colour, but the way the boards respond to the sun, makes the difference.

“Helps create more comfortable outdoor living environments by reducing heat by up to 35%”

CoolDeck® TechnologyOpens in a new tab.

Unlike the next two we will compare, MoistureShieldOpens in a new tab. is a true composite deck board. Made from a blend of encapsulated oak hardwood fibres and polyethylene, extruded into deck boards. And, of course, capped for beauty and durability.

TimberTech’s Azek and Fortress’s Apex™ deck boards are both PVC (polyvinyl chloride) based. Their cores are made from foamed PVC, which reduces heat and weight.

By changing the material, they have made a cooler deck board. PVC has a lower heat retention level than polyethylene and wood fibres. Making their boards naturally cooler than most other composite boards.

“Up to 30 degrees [17°C] cooler than many competitive composite products.”

AzekOpens in a new tab.

To help with rigidity, Apex decking includes bamboo fibres in PVC decking. Which not only increase strength but also reduces weight. Making it a lighter board to transport and to move during installation.

Another advantage that PVC deck boards have is reduced density. By entrapping air in the PVC material, it increases the insulation value. Reducing how long the boards stay hot. With the decking cooling under your feet, a big contrast to most composite decking boards. With their high density, retain heat, continuing to burn your feet as you stand on the deck.

For more reasons and details on how PVC is cooler than composite deckingOpens in a new tab., click the link.

Decking Colour that doesn’t fade with high levels of UV

Even if your deck gets lots of sun you don’t want your deck to fade so much that it looks nothing like the deck you first built. Ideally, you want a deck that is warranted not to fade. Unlike wood most composite deck promises warranty limit fadingOpens in a new tab.. Which is good for a sun deck.

“The Product’s color will not fade from light and weathering exposure, as measured by a color change of more than 5 Delta E (CIE) units. While the Product is designed to resist fading, no material is fade proof when subjected to years of exposure to ultraviolet (UV) rays and the elements.”

TimberTechAzekOpens in a new tab.

 Which is copied almost word for word by all leading brands. Not giving us much to go on in comparing composite decking fading in the sun.

All companies warranty the same limit of 5 Delta E units, which is a good but not showing much  difference between boards. Yes, I could lay all the boards out and see how much they fade in the next five years. But if the next five years are anything like the last five, there will be a whole new patch of new and improved composite deck boards to evaluate by then.

The one kernel of hope is Fortress speaking of their Apex decking boards.

After 3 000 hours of UVA/UVB testing Apex boards only faded Delta E 0.44-47, less than one is unnoticeable to the naked eye. Meaning in Fortress tests, after the equivalent of a full summer of sun, you could not even see the difference from the original boards. The same colour of decking that you fell in love with and picked.

Just to be clear, Fortress warranties the same level of fading as everyone else.

“The Product’s color will not fade from light and exposure to the elements of nature more than 5 Delta E (CIE) Units. Importantly, while the Product is designed to resist fading, Fortress Building Products does not warrant the Product to be fade-proof as no material is fade-proof when exposed to UV rays and other elements of nature.”

FortressOpens in a new tab.

The warranty is practically the same as everyone else, but it does hold promises with their lap test. I guess the question is, will your deck’s sun fade the decking more than the lab test or the same. But Fortress’s Apex holds much promise to keep its colour.

Composite Decking Cap That Doesn’t Disintegrate from the Sun’s Rays

Current composite decking, the cap is the first line of defence. How durable the cap is, determines how well the decking will perform and last. If the cap disintegrates in the sun, the decking will soon follow.

Durable cap=Durable Decking

With a deck exposed to a lot of sun, it’s the strength of the cap withstanding the sun’s damaging ultraviolet oxidation (UV). We have three different approaches used to defend against the sun.

  • MoistureShield by coating their decking.
  • Azek uses additives in the material to protect against the sun.
  • Apex has a distinct cap of different materials to protect the decking in the sun.

Of course, all three claim to have the “strongest” protection against the elements, but lets see how they go about protecting your decking from the sun.

MoistureShield, with their Vision decking line, use a coating process to protect the core of the decking against scratches, stains but more what is our focus the sun’s harmful rays.

“With MoistureShield DiamondDefense™ technology, our liquid polymer coated deck boards create the strongest capped wood composite board on the market to help you prevent damage from scratching and impact.”

MoistureShieldOpens in a new tab.

In short, they paint their decking to protect it against the sun. They would probably explain it differently, but this is largely what is done. The core of the decking is formed, the plank, let’s call it. Then like we have done for years they “coat”, paint the decking to prevent it from breaking down in the sun.

I am not saying this is a bad way. Painting or coating things can provide years of protection. It is practically universally what is done to protect material exposed to the elements. The coating hardens and protects the material from damage.

Natural decking like cedarOpens in a new tab. will always grey, if not “coated,” stained to protect the wood from the sun. Regarding composite decking, as long as the coating has the correct chemicals to block the UV from the sun and adheres for the life of the decking. You are good to go.

On a side note, one of MoistureShield’s boldest claims is their decking has never failed structurally. That the core and the cap protecting it has never failed, broken when correctly installed. That is very assuring. They are upfront that some of their lines will fade in the sun, Vision is not included as one. But at the end of the day, or should we say 50 years, your MoistureShield decking will still be intact.

Azek has taken a slightly different approach. Azek PVC decking has (UV)-resistant additives mixed in with the PVC material to protect against the sun’s harmful rays.

“Boast proprietary polymer caps backed by Alloy Armour Technology®Opens in a new tab. for incredible protection from fading, staining, and weathering.”

Azek

Changing the entire composure of the decking board. Transforming PVC, which is naturally receptive to breaking down from the sun’s UV to something that is not.

On top of that, Azek boards are 100% polymer. There is no wood or organic material that can decompose. Everything is cooked up in the lab to last for years to come.

Fortress’s Apex decking has an acrylic cap. Making it distinctly different in that material is added on top and over the decking core. To protect it against wear but more important the sun’s damage.

“Every board is UV and moisture resistant”

FortressOpens in a new tab.

The advantage of acrylic is that it is naturally resistant to UV damage. Acrylic was first invented for use in the automotive industry. You will see it all over your car, the side door mirror, bumpers, dashes anywhere that needs a durable material that will not be damaged from the sun.

Fortress borrowed this technology to enhance and protect their synthetic decking. It is more expensive than PVC for capping but has superior protection and durability against the sun. Acrylic is more than a coating or additive but an additional material added for the very purpose of protecting against the sun and scratches.

Limited Expansion and Contraction of the Deck Boards in the Sun

When I first started analyzing this beyond what I know from build decks, my first focus was on the decking’s stiffness and strength after experiencing numerous freeze thaw cycles. But I didn’t not find this helpful for evaluating between decking. Especially in relation to decks built in the high sun areas.

Primarily because the discrepancy between decking is minimal. Almost all reports end with some comment to the extent that they were deemed acceptable with “negligence difference between the percentage loss and the percentage loss between composite decking and spruce decking.”

AKA, nothing to see here. They are practically the same.

But one thing I do know, and this is especially true for decking in high sun areas, is expansion and contraction. Not all decking responds to sunlight and heat the same. The extent of expansion and contraction puts a strain on the fasten decking and creates challenges with finishing the decking.

Becoming even clearer when there is lots of sun. With dramatic changes between the deck’s appearance in the cool of the morning and after a full day of sun. The strain put on the decking is especial great for PVC decking which can rapidly expand as the sun comes out and then quickly cool and contract with every passing cloud.

Of these three full sun decking, Azek PVC decking is the worse offender. I love the look and feel of AzekOpens in a new tab., but if room is not given for expansion and contraction, it will become a disaster deck. Being clearly spelled out in their warranty.

“any product failure, product malfunction, condition or damages attributable to the following: (1) improper installation of the Product and/or failure to abide by TimberTech’s installation guidelines, including but not limited to improper gapping;”

AzekOpens in a new tab.

Azek decking will have excessive movement under the sun. Movement that must be accounted for by correct gapping but movement that will impact the decking’s durability in the sun.

To find some hard facts to compare MoistureShield’s Vision line and Fortress Apex is a little more challenging. As I researched the decking movement, it became clear to communicate the information correctly. I would need to get a science degree. Of which I am lacking, just a man with a tool belt building decks.

Apex Expansion/Contraction numbers 4.2 x 10-3

Which means little except that somebody has studied it. I think a better way to understand it is. When comparing board to board, Apex expands less than most composite decking. How much?

“Truer – Expands and contracts about 25% less than other PVC boards”

FortressOpens in a new tab.

In short, generally, PVC decking expands more in the sun than composite and even more than wood, which is minimal. But Apex, with its Bamboo fibres and design, expands less than HDPE decking even though its PVC based. A real win for decking installed on high sun deck.

Less movement=less gapping

Not a deciding factor in which decking you install on your deck. But a factor to be considered. Last summer, I built a PVC deck, and was always frustrated every morning when I saw how large my gaps were when cool. But also knowing that they would mushroom if I installed them tightly in the morning once the full sun came out. Less movement can be a good thing.

Ryan Nickel

A Red Seal carpenter, passionate about building decks to be enjoyed.

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