12 things you must know before building a composite deck
Composite decking is a durable, beautiful, and environmentally-friendly deck material. Since its entry to the market in the 90s, it’s progressed dramatically in looks and technology. With more manufactures and options available now than ever before, it’s hard to know what to buy and what to avoid.
If you’re thinking of installing composite decking, here’s what you need to know:
Types of composite
The composition and quality of composites vary widely. Most are a mix of recycled plastics and reclaimed wood fibers. They are available in either non-capped, partially capped, or fully capped varieties. Some ‘composites’ on the market have no wood fibers at all.
Here’s what is all means:
1 – Non-capped composites
Comprised of a wood fiber and plastic mix, the boards are formed into the shape of a typical wood plank. Due to the manufacturing process, creating a non-capped composite that is aesthetically similar to real wood is not possible.
The original composite decking products were non-capped. But this type has largely been phased out of the market because of issues with warping and advances in technology. Check out our article on how composite decking has changed for more details.
Some manufacturers such as MoistureShield and TimberTech still carry uncapped composite varieties. They are generally less expensive and have a more modest fade and stain warranty.
2 – Capped composites
To combat the issues that the first iterations of composite decking experienced, manufacturers developed the capping technique. This type has a composite core with a hard PVC outer layer on 1-3 sides, which guards against stains, fading, scratching, and warping more effectively than non-capped materials.
Other capped composites have PVC material wrapped around all four sides of the board, making a more complete barrier to water ingress, bugs, and warping. Some, like those produced by TimberTech, have a PVC capping even in the grooved fastener notches for superior protection.
3 – Pure PVC
This class of composite isn’t a combination of materials at all. Pure PVC composites, like Azek decking, have no wood fibers, just high-grade plastics with an ultra-realistic wood look.
Compared to their partially organic counterparts, PVC planks have first-rate heat dissipation, fire resistance, and scratch resistance. They are also extremely lightweight, making them ideal for roof decks. Because this material is a result of testing and technology, it’s durable enough to carry a 30-year fade and stain warranty and a lifetime warranty against defects, termites, and rot.
Shapes of composite boards
Like wooden decking, composites are available in a variety of shapes and sizes. Each type has unique benefits and drawbacks to consider:
4 – Solid
Most similar to a traditional wood plank, solid composite decking has a rectangular profile. It’s mounted by screwing through the top, just like wood. It can be heavier than other types of composite, but has strong rigidity.
5 – Slotted
It’s just like solid composite, but with a notch cut down either side for use with a hidden fastening system. Using hidden fasteners keeps to PVC cap intact for protection and makes a beautiful deck surface, without screw holes. Some manufacturers don’t coat the notch with a protective PVC cap, leaving it more vulnerable to water ingress and insect penetration.
6 – Ridged
Only one side of this board is usable, as the underside has cut-outs to reduce weight and cost.
7 – Hollow
Much lighter than other composite boards, but obviously plastic. End caps are used to block insects and small animals from nesting in the hollow cavities.
8 – Choosing a Colour
While colour is not the most pertinent decision to be made, it’s the most emotionally-charged one. Each manufacturer offers a variety of colours to choose from. As long and you’re choosing between top brands like TimberTech, Azek, and Trex, you can be confident in your decision and choose the style and price that best suits your needs.
Understanding how you want your space to function can help you choose the best colour pallet. When considering colours, ask the following questions:
- Is the space an extension of your indoor space?
- Do you want to blend the deck color to the outdoors?
- Will your railing match the trim or overall architectural style of the house?
Composite Deck Construction
Building a deck is a favourite DIY project. However, considering the cost and technical requirements of composite deck construction, it’s best left to a professional deck builder or carpenter.
Here’s a few composite deck construction considerations:
9 – Permits
Before you get started, find out if a building permit is required for your deck project. Check out our blog to find out if you need a permit for your metro Vancouver deck construction.
10 – Joists
Framing for a composite deck isn’t the same as a wooden deck. The plastic materials in composite decking require strict support to avoid bowing or warping when heated by the sun. The required joist span is 16-inches on centre, or 12-inches on centre when running boards at a 45-degree angle. Also, composite decking typically comes with a warranty of 20 years or more. To comparably extend the lifetime of wooden joist, top contractors wrap them in a UV-treated waterproofing membrane before installing composite planks.
11 – Usability
If you want dry space below your deck for storage or outdoor living, then consider a water management system like Azek’s dryspace. If you are doing outdoor living space below then esthetics come into play: how do you want the bottom of your framing to look? Azek’s dryspace attaches to bottom of joist and gives finished surface, so soffit installation isn’t required.
12 – You’re not alone
Don’t be overwhelmed or under-informed when you’re choosing composite decking. Citywide Sundecks and Railings is an expert deck builder with tonnes of experience in installing composite decking. We’ve vetted the top manufacturers and will guide you through making the best deck-cisions for your home.