Different Types of Composite Decking You Need to Know!


There are 5 different types of composite decking available on the market. From profile to finishes and the material they are composed of. You have many types to choose from, and let’s not forget how they are manufactured.

Types of Composite Decking Finishes

This is the most noticeable. The reason you will often be attracted to one board over another.

The finish creates the look of the board, how close it looks like wood.

Creating texture and the resulting traction the decking provides.

There are two main finishes of composite decking.

  • Capped
  • Uncapped

Composite Decking With a Polymer Cap

This is now the dominant finish of composite decking and for good reasons. The cap solved many problems that earlier generations of composite decking had. From mould to rot and fading.

The cap also improves the appearance of the decking with more colour variation, streaking and texture.

Because the cap is only a thin layer, the manufacturer can spend more money for better quality material. Increasing the performance of the decking.

Similar to plywood veneers. The mill can save the best-looking wood for the outside, which you see, and create strength with the lower quality material in appearance without compromising the board’s appearance.  

The same is true with capped composite decking. Composite decking colour is only used for the cap keeping the core’s cost down but still enhancing the decking appearance.

Fiberon was one the first to innovate with capped composite decking and still leads with over 30 cap finishes to choose from.

Amount of Capping

As a sub-note to capping, the amount of capping also varies between boards.

There are completely wrapped boards like TimberTech’s Terrain Collection and Fiberon’s Concordia which are wrapped on all four sides. Top, bottom and both sides.

Even smaller side note, TimberTech’s groove is included in capping, 360°. Wherewith Fiberon’s groove is cut into the board and cap.

The much more common though, is capping on 3 sides only. Trex has always been faithful and consistent in this approach. Trex caps the top of the board and over the edge stopping at the top of the groove.

Making everything that you see, feel and directly exposed to the elements capped and protected. Everything else is left uncapped.

Often because of the expense of the cap, higher-end boards will be completely wrapped. With the economical, budget lines are only capped on 3 sides.

But honestly, once installed, it will be hard to tell if the decking is capped on all 4 sides or only 3.

The one exception and one that FiberonOpens in a new tab. pushes is with a raised deck. When sitting on the patio under the deck you will be able to see the finish of the underside of the boards.

Uncapped Composite Decking

This used to be the dominant version of composite decking. In the late ’90s, when composite decking was just being introduced, it was the only type you could buy.

My times have changed, especially with composite decking.

Now, most brands have discontinued making uncapped decking and strictly offer capped composite.

Two brands that offer uncapped composite decking are MoistureShield and Ultra Deck. Not entirely, but alongside their capped decking.

With MoistureShield it’s their Vantage line.

Don’t mistake this as poorer quality, as they still back it with their 50-year structural warranty. But they are upfront about the fact that it will fade in colour without the cap. Giving you a much lighter deck in 6 months.

Nor is it necessarily cheaper. Vantage, costing roughly the same as Trex’s capped high-end Transcend boards. But still, they often will cost less than other brands from the same brand.  

Profiles of Composite Decking

Next to the finish, this is the most noticeable difference, especially before installation.

3 Popular Profiles

  • Solid
  • Scalloped
  • Hollow

Solid

Like the name says, solid composite decking is solid with no material reduction designs. Giving a full 1′ (25mm) of material. One exception is Trex’s Select line which is only 7/8″ (22mm) thick. Solid just thinner compared to other solid deck boards.

Still not ideal but does make the finishing of the decking endsOpens in a new tab. less critical. With the cut ends looking similar to end cuts of 5/4 pressure treated decking. Different colour and texture but no glaring holes or cavities.  

Scalloped

Reduces both the weight and cost by removing channels of material from the underside of the decking. Done in a way not to affect the strength of the decking, with most still able to span 16″ (400mm).

The number of scallops may vary. Some brands will have 5 smaller scallops and other 3 larger ones. But both have the same effect. Lower price and weight. Which is why almost all budget composite decking are scalloped.  

Hollow

This is not as popular as scalloping, but two examples are NewTechWood and UltraDeck. With NewTechWood, all their composite decking is hollow. With UltraDeck, it is only their Natural line that is also uncapped.

Similar concept as scalloping, reduce weight and costs by reducing material. But without changing the bottom of the decking. Which allows NewTechWood to provide two finish options on the same board. The boards are reversible with either brushed or woodgrain finish.

There are some debates that hollow boards respond to the elements less increasing lifespan and are cooler with less material. I am not convinced yet, but it is something to be considered.

Composite Decking Different Edges

Primarily about installation, but there are two typical edges for composite decking.

  • Square
  • Grooved

Grooved

They are designed for hidden fasteners. Speeding up installation with a ready lip for the clip or biscuit to hold down the board.

Like capping, once installed, will impact appearance little. Except for not having to see ugly screw heads marring the surface for the decking.

Square Edge

Are ideal for the edge of the deck and stairs, with a completely finished edge not distracting from the deck’s finish.

Sometimes square edge decking is often installed with Cortex plugs hiding the fasteners.

Almost all companies offer both grooved and non-grooved an exception is Wolf, which uses Camo edge screws instead of biscuits and clips for hidden fastenersOpens in a new tab..

Material Include in Composite Decking

There are four true material blends of composite and one that I include as low-maintenance decking.

  • Wood/Plastic Composite
  • Mineral Based Composite
  • Bamboo based Composite
  • Rice Hull Composite
  • PVC (polyvinyl chloride)

Almost all composite decking are a blend of wood fibres and recycled plastic. Roughly a 50/50 blend, some will have as much as 70% wood fibres, but that is rare.

The type of wood will vary, MoistureShield uses oak, but Fortress uses bambooOpens in a new tab.. Yes, I know technically not wood but acting the same way.

A recent departer from this blend is DeckoratorsOpens in a new tab.. Deckorator has 4 lines of mineral-based compositeOpens in a new tab.. Which has virtually no thermal expansion or contraction, better traction, with reduced weight. All reasons to consider a mineral-based composite instead of wood.

PVC decking like Azek, Fiberon’s Paramount are made without organic material. Which reduces heat retention, weight and the possibility of rot. With nothing to rot.

Often on the higher end for price with its longer warranties and life. One exception is Wolf’s Serenity. A full PVC board but priced similar to many composite deck boards.  

Different Ways to Manufacture Composite Decking

There are 2 main ways to manufacture composite decking.

  • Extruded
  • Compressed

Extruded is the most popular used by most decking brands.A simple sausage technic for making decking. The material is blended and then extruded, forming the decking profile. With capped composite decking, the cap is often extruded with the core making a solid board with little chance of the cap peeling off.

Compression is less common, with few brands compressing their decking. One exception is EnvisionOpens in a new tab.. Envision forms their decking by placing the material into a form and then compressing out the air. Creating a solid board with minimal trap air.  Claiming that this process makes a dense and stronger deck board. They do back this process with a 25-year warranty. Comparable with most other decking companies.

Ryan Nickel

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

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