‘Wood Plastic Composite’, or WPC for short, is a composite material that impresses in outdoor areas compared with timber floorboards, in particular thanks to its easy-care properties and weather-resistance. In spite of these advantages, some owners of WPC terraces complain of deformation, scratches or even boards coming loose. We spoke to Nedjeljko Grežina from outdoor design firm Freiraumgestalter about the various types of damage and what causes them. Read on for practical tips on how to avoid damage and replace your floorboards in the event of damage.

Choose good quality WPC floorboards to minimise the risk of damage from the outset. But how can you tell which products are good quality? WPC expert Nedjeljko Grežina from Freiraumgestalter offers the following three tips for buyers:

Don’t be tempted by products that are brand-new on the WPC market. Many new products have been taken off the market again quickly due to excessive complaints.

Do a thorough search for user reviews of your preferred product. If few users have had negative experiences with it, you can buy it without reservations.

However, even the best quality does not rule out damage. You should buy a few extra floorboards just in case, and store them in your garage, basement or loft until you need them.

In winter, road grit often sticks in your shoe treads. When you walk across your WPC terrace in the same shoes, you can cause scratches. Pets also leave scratches – if dogs or cats also use the terrace, their claws can also scrape tiny notches in the floorboards.

"When buying WPC floorboards, note the scratch resistance category. Especially if you have pets, you should never lay soft floorboards. On the other hand, hard WPC floorboards are not immune to scratches either. If you see a scratch, do not try to grind it away immediately (contrary to some cleaning tips)," says the expert. He advises owners to relax: "There will always be another scratch. And another. All together, they create a natural overall look."

If heavy flowerpots or sunshade stands weigh down on the WPC terraces, floorboards can subside and become permanently deformed.

How to avoid this:

Before laying, plan where you want to position garden furniture and plants on your WPC terrace. To prevent the floorboards bending in these areas, reduce the spacing between the substructure beams. "If you are not sure whether the spacing you have planned is small enough, contact your WPC manufacturer for advice." Our expert warns: "Using too many beams can make substructure alone prohibitively expensive."

Extremely large hailstones are rare, but if the worst comes to the worst, heavy impacts like this can leave marks on WPC terraces. Also, minor damage occurs all the time when WPC is used in the hospitality sector, for example when heavy items are dropped onto the floorboards, causing light spots or even holes in the floors.

They can be avoided or removed as follows:

Hard blows can force the oxygen out of the floorboards, leaving light spots. "The spots fade again of their own accord after a while," explains the expert. If you want to remove the spots immediately yourself, Nedjeljko Grežina has the following advice: "Scrub your terrace with mild soap suds. That washes the spots away again."

If the heavy items fall directly onto a hollow chamber in a WPC floorboard, the main risk in that area is that the accident leaves a hole in the floorboard. "Solid floorboards are always a better choice for applications where that could happen," says Grežina.

If WPC floorboards are exposed to strong sunlight, their colour can fade. As a rule, sunlight causes the WPC floorboards to fade slightly over a one year period. After that, they stay roughly the same, lighter shade.

How to avoid this:

Of course, the floorboard colour is always going to fade slightly. To ensure that your terrace is the colour you want after one year at the latest, you should ask to see faded samples of your preferred WPC boards. If you want your floorboards to stay the same colour, choose coated floorboards. The coating prevents the colour fading, but leads to a more artificial look.

Find garden designers and landscapers that could help you with your terrace

When the sun shines on the WPC floorboards, they heat up considerably, especially in summer. If the flooring reaches a certain temperature, the heat can even cause deformation.

How to avoid this:

To restrict significant heating in the summer, Grežina recommends covering the WPC terrace with roofing, in addition to choosing lighter shades. "However, you should avoid glass roofing," warns the expert. "Glass enhances the heating effect when strong sunlight shines through it."

To prevent the WPC floorboards bulging, comply with the recommended spacing, as well as choosing a WPC composite with more wood. It is the plastic in the floorboards that expands when heated, especially longitudinally.

If moisture from the last rainfall or puddles from watering plants cannot dry properly, the wood fibres in the WPC expand. With hollow chamber floorboards, there is also a risk of water gathering in the chambers. This can result in detachment from the anchors, deformation of the floorboards or unpleasant smells.

How to avoid this:

In particular, hollow chamber WPC floorboards should never be laid without a slope of one or two percent (depending on the manufacturer), leading away from the house. "Water can quickly build up in hollow chambers laid without a slope, causing waterlogging damage. You can also avoid the WPC floorboards becoming soaked by strictly observing the spacing between the ends of the floorboards and adjacent objects (building walls, stone walls and similar items). It serves as rear ventilation," says the expert. Additional drainage holes drilled into the WPC with conventional wood tools can also help. Here too, Grežina has some advice: "In such cases, ask the manufacturer of your WPC floorboards. Or even better: Have the floorboards laid by a specialist who knows all of the manufacturer's recommendations and what to do in exceptions."

In the expert’s years of experience, the most common cause of deformation and splitting of WPC floorboards is incorrect installation. Grežina explains: "The recommended spacing is often ignored when laying the floors." Also, users can cause damage intentionally via minor details like incorrect screws, excessively large terrace units, or floorboards stored incorrectly just before installation. That can lead to bulging of the floorboards or discolouration around the screws.

How to avoid this:

Due to the frequent installation errors, Grežina recommends reading the manufacturer’s laying instructions carefully: "If you don’t follow the required specifications precisely when laying, you will void your warranty!"

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