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PVC vs Composite: What Is the Best Maintenance-Free Decking Material?

PVC vs Composite: What Is the Best Maintenance-Free Decking Material?

July 11, 2018

PVC vinyl (polyvinyl chloride) and composite materials provide many options when it comes to constructing decks. They replicate the look of wood but don’t require as much maintenance as wood decks.

Homeowners who want to add a deck to their property have to compare PVC vinyl vs. wood and decide which is best for their home. They must make their decision based on the climate in which they live.

PVC Vinyl vs. Wood Decking

PVC vinyl and composite wood decking are often confused. They both contain synthetic material.

However, the materials are so different and they each perform in different ways. When used for decking, the deciding factor is often how they stand up to climate conditions.

Another consideration is maintenance. A composite wood deck requires less maintenance than a 100% wooden deck. Though, a PVC vinyl deck is an almost maintenance-free decking material.

What is PVC Vinyl Decking?

PVC vinyl decking contains only one material. That material is polyvinyl chloride. It is the same stuff you find in vinyl fences and siding. It is a 100% recyclable material that looks like natural wood.

Because it is plastic, it is a maintenance-free decking material. It won’t build up mould or mildew. Over time, a PVC vinyl deck holds its colour. It cleans easily and doesn’t stain. Plus, a PVC vinyl deck is scratch resistant.

That said, plastics have several known issues. These issues stem from the plastic’s lack of resilience to harsh weather conditions.

PVC Vinyl Decking and Heat Expansion

First, any plastic material is subject to linear expansion. When exposed to heat, the molecules inside the plastic expand. Engineers take this into account during design.

They calculate the estimated linear expansion coefficient. PVC vinyl decking has an expansion ratio of 54-100. Compare that to pine, which is 5-110, or steel’s 11-110.

Though as you can see, PVC expands quite a bit. On a hot summer day, boards on a PVC vinyl deck can expand enough that the deck edge is no longer even.

PVC Vinyl Decking and Heat Retention

PVC vinyl decking retains a good bit of summertime heat. It gets too hot for walking in your bare feet. This puts a damper on homeowners who want to enjoy their deck.

It’s also an inconvenience when all you want to do is cross the porch to get to your grassy yard.

Manufacturers are working on what they call “cooling technology” for PVC and composite decking alike. Though, older decking materials will still get hot during the summer months.

PVC Vinyl Decking and Cold Weather

Cold weather presents its own issues for PVC decking. Plastics become brittle when exposed to extremely cold temperatures.

Once they become brittle, they can crack. This wouldn’t present too big a problem with a vinyl fence. It could present a bigger problem with decking.

PVC Vinyl Decking and UV Light

UV light is another consideration. When exposed to prolonged sunlight (as all decks are), the plastic decays over time. When it does, you will see a white power on the surface.

Over time and seasons, the repeated expansion and contraction of PVC decking wears on the decking. It can also damage the fasteners.

All of these factors combined could shorten the life of your PVC deck. Over time, safety becomes a very real issue.

Composite Decking

Manufacturers introduced composite decking in the 1990s. The man often credited with inventing it is Roger Wittenberg and his Trex Company.

Many brands of composite decking contain half wood fibres. They are all made from recycled plastic. Composite wood decking is a solid, so it is the same colour all the way through.

This makes the ends of boards less noticeable. It is available in many colours, thicknesses, and grain patterns. A composite wood deck should last about twenty years depending on climate conditions.

Composite decking contains two different types of plastic. It contains either polypropylene or polyethylene. Both of these are more stable than PVC. Also, both are blended with bamboo or wood.

The composition changes how each product performs. Composite decking doesn’t have the same issues as PVC decking because of the wood additives.

Composite Decking and Moisture

One drawback to composite decking is that it is susceptible to moisture. Because a composite wood deck is made partly of wood, it is subject to moisture and water damage over time.

Though, it does have several advantages over PVC decking.

Composite Decking Has Less Expansion

Polypropylene or polyethylene have better expansion coefficients than PVC. They are of 59.4 and 72-90, respectively. If polypropylene is reinforced with fibreglass, the linear expansion coefficient is only 32.

The expansion of composites varies with type. But, if it has a ratio of wood flour to plastic above 40%, the composite is more rigid and dimensionally stable.

Composite Decking and Rigidity

Rigidity is an advantage when it comes to deck flooring. You never want to walk across a bouncy deck.

A lower quality composite wood deck does tend to bounce. A workaround for that is to construct the deck joists closer together. That raises the cost of building your deck.

Using a higher grade composite for decking is cost-effective. The stiffness means it can cover more distance than PVC. It’s also easier for one person to install with less imperfection in the framing.

What Is the Cost of PVC Vinyl vs. Wood Decking?

If you’re thinking of adding a deck to your home, the cost is, of course, a primary consideration. For composite decking, the average cost of materials and installation can range around $35-$50 per square foot.

The average price of PVC-based decking varies depending on whether your slats are solid or hollow. Solid can be on par with composite or higher in cost depending on the style and manufacturer.

Which Do You Choose?

If you live in a fairly moderate climate, both PVC and composite should perform well. Deciding on PVC vinyl vs. wood may come down to cost and convenience.

If you live in a harsher climate, you’ll see extreme temperatures in either summer or winter. To get the most out of your investment, you may want to go with a composite deck.

If you have any questions about either type of deck, please contact us.

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