Vinyl Decking Vs. Composite Decking

Is the Price Worth the Cost?

Vinyl decking has long been a reliable, low maintenance solution for waterproofing decks and outdoor living space but in the last few years there has been quite a buzz about WPC decking, or wood plastic composite decking – the new kid on the block for low maintenance decking options. Information and images are showing up from sources like the article, “Some Issues with Composite Decking” from home inspector, Jason Horn that raise more questions, and possibly some doubt about composite decking.

If you are comparing options for building or renovating a deck, doing a little homework will save you a lot in the long run for getting the most value for your investment.

Duradek and Durarail bring protection and style
to your outdoor living space.

The Price You Pay for Your Deck

While actual costs will vary greatly from project to project, composite decking has shown costs of 2 to 5 times more than decks built from pressure treated wood, and nearly twice as much as a deck protected with PVC Vinyl. While the cost of material contributes to this difference, a lot of the extra cost is attributed to labor. The composite decking boards have less strength than regular wood and have a tendency to sag or bow, so the supporting joists must be placed closer together. Additionally, each board must be pre-drilled prior to installation during the fastening process.



Composite boards bowing and sagging
- image from GardenStructure.com

While waterproofing your deck with a vinyl membrane will contribute to the overall cost of the material for your decking project, the installation is handled by expertly trained installers and the vinyl can be installed and walked on within the same day. Additionally, the primary substrate of the deck is still a solid wood foundation, which protected by Duradek vinyl, can last for decades.

Duradek and Durarail provide long lasting results.

The Performance of Your Deck

Like many other decking materials, composite decking boards need room to expand and contract. There have been many instances of composite boards cracking and splitting along the edges, and even some occurrences of deterioration along the primary surface of the boards. View for yourself some of the unwelcome results with composite decking. Some composite decking manufacturers have attempted to resolve this issue by ‘capping’ the boards with a protective coating,  however some of these composite deck boards are showing swelling at the ends where there is nothing to keep moisture from getting into the wood fibers.

Composite boards showing signs of flaking.

But beyond the deck surface, it is the deterioration of the wood joists underneath the composite that must be considered. The drying qualities of composite decking on the surface can be counterproductive to the actual structure of the deck. While wood decking will absorb some moisture and eventually release it to the air around it, composite decking does not absorb water. Any moisture that gets trapped underneath the composite decking and on top of the wood joists would tend to stay there and keep the joist from drying properly, making the joists more susceptible to rot and decay. For some interesting comments and images, check out “Lots of Noise About Composite Decks” on the Business of Building Decks and Fences blog.

Duradek vinyl membranes virtually eliminate the issue of wood rot. The vinyl completely seals the deck with a water-tight surface and provides roofing grade protection for the structure underneath. The water is not absorbed by the deck, but drains with a natural slope and water routers and diverters that keep the structure protected.

If you are interested in discussing deck waterproofing options with a Duradek professional installer, find a Duradek dealer near you for a personal consultation on your decking project.