Laying WPC boards – assembly instructions for decking boards

Well-founded planning ensures that the laying work runs smoothly and reduces losses of time and money to a minimum.

Determination of needs

• Measure the area exactly.
• Determine the orientation of the planks.
• Design the substructure at right angles to this.

Once the dimensions have been determined, it is no longer difficult to determine the material requirements for floorboards and aids. Decking boards are available in standard lengths of 3 to 6 meters or in special sizes between 1.50 meters and 13 meters. The multiplication of the area width and the board requirement per m² results in the number of boards. In addition, there are the basic profiles, which are usually supplied in a uniform size in order to ensure stability at a 90 ° angle to the terrace surface. In the substructure, it is not necessary to lay the profiles close to you, but at a distance of 40 cm. The number of mounting brackets required results from the total area divided by 40.

Material and tool list

• WPC boards, base profiles and mounting brackets according to the requirements calculation.
• Cordless screwdriver with low torque.
• Circular saw or jigsaw.
• Hammer, folding rule, square, string and pen.
• Swivel feet for the 1-2 percent incline of the surface.
• Expansion joint profile tape if required.
• Weed or garden fleece.

It makes sense to include a small reserve for all materials, because it is extremely annoying to interrupt the assembly of decking boards because a profile, assembly bracket or swivel base is still missing.

Preparatory work

Once all the materials are ready at the construction site, the laying work begins with the preparation of the floor.

Underground

There is no doubt that the assembly of WPC boards is easier, the more level the surface is. Stone slabs that are already present can be built over excellently. Otherwise, the experienced do-it-yourselfer creates an approx. 10 cm thick drainage made of gravel or chippings and pulls it as smoothly as possible with the rake. Before doing this, it is essential to define the zero point as the height at which the upper edge of the finished terrace will later be located. House corners or ventilation shafts provide good orientation. If, as a result of the addition of drainage, plank height and swivel feet, the total height is above the desired zero point, it is necessary to dig the floor so deep that it fits.

Plant protection

Foresighted hobby gardeners lay a weed fleece over the drainage. The geotextile is permeable to water and air, so that weeds have no chance and waterlogging cannot develop. If the garden fleece is laid with an overlap of 10 cm to 15 cm, no further fastenings are required.

Ventilation clearance

WPC boards are largely made of wood fibers. When it rains, they sometimes swell up slightly, which is a completely natural process, even if the water flows away quickly due to the slight incline. As a result, an overhang of 2 cm to 5 cm from the house wall to the edge of the first plank is set up as standard. In the event that the terrace area protrudes beyond the house wall, a taut cord serves as a guide.

The preparatory work is now complete and the actual assembly of WPC decking can begin.

Tip: An expansion joint profile tape between the house wall and the first board takes on the function of silicone sealing in damp rooms.

Laying in open construction

The swivel feet are now placed on the weed fleece, which on the one hand are designed for a gradient of 1% to 2% and on the other hand prevent undesired contact with the ground of the base profiles. If a smooth surface is available, the swivel feet are placed on rubber pads. If the WPC planks are laid on the stone slabs or tiles of an existing terrace as part of a renovation, which already has the required slope, the swivel feet can be saved in favor of cheaper rubber or cork pads.

• Screw the base profiles to the swivel feet or click on them.
• Experience has shown that the distance between the profiles is 40 cm.
• First screw the start and end clamps to the base profiles.
• Push the WPC boards into the clamps and fix them.

After the first and last decking boards have been installed, the rest of the installation is carried out according to a uniform pattern: insert the installation aid or spacer between the boards. Then push the lath, insert the mounting bracket and press it on. The spacers ensure a uniform gap of 8 mm as an expansion joint.

Laying in a closed construction

If a closed terrace area is desired, the minimum height of the construction is 8 cm to ensure all-round ventilation. In addition, there are no laying aids and special stainless steel clamps are used.

• Joint hoses are used instead of spacers for a gap-free terrace surface.
• The ventilation joints to the house wall remain open so that moisture can escape.
• In this case, expansion joint profiles are not used.

Tip: The minimum installation height of 8 cm is achieved by simply installing 2 base profiles on top of each other.

Popular laying patterns

Laying WPC boards of the same length with continuous joints appears at first glance to be the simplest option. Depending on the size of the terrace, installing very long boards can be problematic. The wood-plastic composite scores with a high level of stability; nevertheless, slight fluctuations cannot be completely ruled out. With a 6 meter long deck board, a minimal curvature of 1% is a full 6 cm. This fact does not make the assembly impossible, but at least makes it more difficult. If you want to avoid such complications and at the same time prefer a relaxed laying pattern, you can opt for one of the following alternatives:

• Lay WPC boards of different lengths alternately.
• Install decking boards of the same length with transverse middle pieces.

A diagonal laying pattern – starting in a corner – is in principle also conceivable. However, there is a high loss due to scrap, which in view of the valuable WPC material drives up costs unnecessarily.

Extending the base profile

The majority of suppliers of WPC boards offer the associated basic profiles in a uniform length. If the profiles are too long, they can easily be shortened using a fine-toothed saw. In contrast, installing a large terrace can result in the profiles of the substructure being too short. In view of this fact, the knowledgeable builder knows what to do:

• Mount the extension with a precisely balanced overlap.
• The last board on the ending base profile is also the first board of the next profile.
• This one WPC board must be fixed to both profiles with clamps.

In addition, the distance between the base profiles is reduced from 40 cm to a maximum of 10 cm to ensure stability.

Straighten and seal

Once all the WPC boards have been securely laid, the builder will straighten the ends. A chop saw creates smooth cuts for a harmonious appearance. Color-coordinated end caps give the new terrace the finishing touch and at the same time protect against the ingress of moisture. A file can be used to remedy the situation where a few ridges can still be seen. When installing decking made of wood-plastic composites, this should be the absolute exception, because the dreaded wood splinters are usually not visible due to the plastic content.

Alternatively, shiny angles made of aluminum are suitable to highlight the ends of the boards. Make sure that there is at least 5 cm clearance between the corner and the end of the board as a ventilation opening.

A decidedly professional look is created when square timbers in matching colors are used as a finish. A base profile serves as a support on which the edge boards are simply screwed. The distance to the house wall must of course not be undershot as a result.

Tip: Since WPC boards are an extremely solid material, every screw connection should always be pre-drilled.

Install lighting

The creative do-it-yourselfer conjures up a touch of mystical romance in his new terrace by integrating discreet LED lighting into the floorboards. He saves a lot of time and effort if the supply and discharge lines are laid in good time, i.e. at the same time as the substructure is being installed. The luminaires themselves are then quickly installed.

• Use a circle cutter to drill suitable openings in the WPC boards.
• Insert the lamp housing and fasten according to the manufacturer’s description.
• The connection cable should lead out at the side under the boards.

Knowledgeable do-it-yourselfers save themselves a cable clutter by opting for solar-powered LED lights and save electricity costs at the same time.

Conclusion
Innovative WPC boards give the terrace a cozy, warm aura that invites you to linger. Since the wood-plastic composite combines the advantages of both components, more and more house owners are choosing to install WPC decking. Thanks to the uncomplicated laying technique, even do-it-yourselfers are able to use the new flooring in their extended living room. A stable substructure made of base profiles is given a slight slope away from the house by means of swivel feet so that no water collects. This is followed by the noble planks, which are very easy to install using a click system and fastened with clips. Last but not least, a decorative border design and the breathtaking terrace is ready.