I. Pre-Installation Preparation: Laying the Foundation for Installation

Preparation before installation directly affects the long-term stability, with key focuses on substrate treatment, material preconditioning, and tool preparation:

1. Substrate Treatment (Core Requirements: Flatness, Load-Bearing Capacity, Drainage)

The substrate for WPC installation should be selected based on the specific scenario, with core requirements of no water accumulation, meeting load-bearing standards, and a flat surface:

• Outdoor Ground (Courtyards/Terraces):

• For hardened surfaces (concrete/asphalt): Ensure the surface flatness error is ≤ 3mm per 2m, and reserve a drainage slope of 2‰ - 5‰ (to prevent water from seeping into WPC gaps).

• For soft surfaces (soil/lawn): First lay a 10 - 15cm thick gravel cushion (with a particle size of 5 - 10mm), then cover it with 3 - 5cm thick medium sand for leveling, and finally lay a waterproof geotextile (to separate soil from WPC and prevent insect infestation).

• Load-bearing requirements: Outdoor platforms should withstand ≥ 250kg/㎡ (including the weight of people and furniture), and boardwalks should withstand ≥ 300kg/㎡.

• Walls/Ceilings: The substrate should be a solid wall (brick wall/concrete wall) or anti-corrosion wooden keels (which need anti-corrosion treatment in advance). Ensure the substrate is firm without looseness, and the wall flatness error is ≤ 2mm per 2m.

2. Material Preconditioning (Key Points: Adapting to the Environment, Classified Placement)

• Adapting to the Environment in Advance: WPC may have "environmental stress" after leaving the factory. Transport the materials to the installation site and stack them outdoors (avoid direct sunlight) for 24 - 48 hours to allow them to adapt to the on-site temperature and humidity, thereby reducing subsequent deformation.

• Classification and Screening: Classify and place the materials by length and texture. Prioritize the use of materials from the same batch with the same texture during installation to ensure a uniform appearance. If any material is found to be bent or      cracked, replace it in a timely manner.

3. Tool and Auxiliary Material Preparation

II. Core Installation Methods: Detailed Explanations by Scenario

The installation methods of WPC vary significantly depending on the application scenario (ground/wall/boardwalk). The following are the installation steps for the three most common scenarios:

(I) Outdoor Ground/Terrace Installation (Most Common: Keel Laying Method)

Suitable for courtyard, terrace, and balcony floors, it consists of two steps: "keel laying" and "board fixing". The core is to disperse weight through keels and reserve expansion gaps:

1. Snapping Positioning Lines:

• Use an ink fountain to snap the positioning lines of keels on the substrate. The keel spacing should be determined based on the thickness of the WPC board:

• For boards with a thickness ≤ 15mm: Keel spacing ≤ 300mm.

• For boards with a thickness of 15 - 20mm: Keel spacing ≤ 400mm.

• For boards with a thickness ＞ 20mm:  Keel spacing ≤ 500mm (excessive spacing will cause the board to deform when stepped on).

• At the same time, snap the drainage direction line to ensure  the keel laying direction is consistent with the drainage slope.

2.Fixing Keels:

• Keel selection: Prioritize WPC keels (with the same material as the board to avoid differences in thermal expansion and contraction between different materials) or anti-corrosion wooden keels (which need to be coated with anti-corrosion coating twice in advance). The cross-sectional size of the keel is recommended to be ≥ 40mm × 25mm (to ensure load-bearing capacity).

• Fixing method: Fix the keels to the substrate using expansion bolts (length ≥ 80mm), with a bolt spacing ≤ 500mm. There must be bolts  to fix the joints of the keels (the joints should be staggered to avoid being in a straight line).

• Leveling inspection: Use a level to check the flatness of the keels section by section. The error should be ≤ 2mm per 2m. If it is not flat, use gaskets to adjust (to avoid height differences of the boards later).

3.Laying WPC Boards:

• Board direction: It is recommended to lay the boards perpendicular to the keels at 90° (for more uniform force bearing). For aesthetic purposes, diagonal laying (45°) can be adopted, but the keel spacing needs to be reduced (to reduce the span of the boards).

• Fixing screws: Use stainless steel self-tapping screws to fix  the boards from the side (or pre-drill holes on the surface). The screws should sink 1 - 2mm into the board surface (to avoid protrusions that may scratch feet). Both ends of each board must be fixed on the keels, and one screw should be fixed every 300 - 400mm in the middle.

• Reserving Expansion Gaps (Key Point):

• Between boards: Reserve a 5 - 8mm expansion gap horizontally (on the short side) to prevent extrusion deformation due to temperature changes.

• Between boards and walls/columns: Reserve a 10 - 15mm  expansion gap vertically (on the long side). Especially in outdoor areas with large temperature differences, the gap should be appropriately widened.

• For large-area laying: A 20 - 30mm "segmented expansion gap" should be set every 6 - 8m (or when the area exceeds 10㎡) (filled with expansion gap strips to avoid overall deformation).

        4.Finishing Treatment:

• Cutting edges: Use sandpaper to polish the cut edges of the boards to avoid burrs.

• Gap sealing: In outdoor scenarios, apply silicone weatherproof adhesive (waterproof type) to the gaps between the boards and walls/columns to prevent rainwater from seeping into the substrate.

• Cleaning: Wipe the surface of the boards with a damp cloth to remove dust and adhesive residues left during installation.

(II) Wall Installation (Two Methods: Keel Hanging/Direct Bonding)

Suitable for outdoor enclosing walls and indoor feature walls, the core is to ensure firm fixing and avoid water accumulation residues:

(III) Boardwalk/Waterfront Platform Installation (Enhanced Load-Bearing and Anti-Corrosion)

Boardwalks are mostly located in outdoor humid environments (e.g., by lakes and rivers), so installation requires additional enhancement of anti-corrosion, load-bearing, and anti-slip properties:

1. Substrate upgrading: Concrete foundation beams (with a spacing ≤ 2m) need to be built, and embedded parts (for connecting with keels) should be pre-embedded in the foundation beams to prevent the keels from directly contacting the ground (for anti-corrosion purposes).

2. Anti-slip treatment: Choose WPC boards with a textured surface, or drill holes on the board surface (with a hole diameter of 5mm and a spacing of 100mm) to enhance anti-slip performance.

3. Drainage design: When laying the boards, they should be inclined outward at 3° - 5°, and an 8 - 10mm wide drainage gap should be reserved between the boards (wider than that of ordinary ground to accelerate drainage).

4. Guardrail connection: If guardrails need to be installed on the boardwalk, guardrail connectors (stainless steel) should be pre-embedded  on the keels in advance, and the guardrail columns should penetrate the keels and be fixed on the foundation beams (to ensure firmness).

III. Key Notes: Avoiding Subsequent Problems

1. Thermal Expansion and Contraction Treatment (Core)

• The coefficient of thermal expansion and contraction of WPC is  approximately 2 - 3 times that of solid wood (the length changes by about 0.1% for every 10℃ change in temperature). Therefore, expansion gaps must not be omitted.

• In high - temperature areas (with summer temperatures ≥ 35℃), the expansion gaps should be appropriately widened (e.g., an 8 - 10mm gap between boards). In low - temperature areas (with winter temperatures ≤ -  10℃), check whether the keels are heaving due to freezing before installation to prevent the boards from being squeezed and cracked.

2. Selection of Fasteners (Anti-Corrosion)

• Screws/expansion bolts made of stainless steel 304 (for  ordinary outdoor use) or 316 (for coastal and high - humidity environments) must be used. Avoid using iron fasteners (which are prone to rust, leading to loose boards and pollution).

• The length of the screws should match the thickness of the boards. Screws that are too short are easy to loosen, while those that are too long will penetrate the boards (affecting the appearance).

3. Avoiding Water Accumulation and Direct Sunlight

• For outdoor installation, ensure the substrate has smooth drainage, and it is forbidden to lay WPC in low - lying areas where water  accumulates.

• For scenarios with long - term direct sunlight (e.g., rooftop terraces), it is recommended to choose WPC boards with dark colors or UV -  resistant treatment (to reduce UV aging and extend the service life).

4. Post - Installation Maintenance

• For daily cleaning, wipe the boards with clean water or a neutral detergent. Avoid using strong acids and alkalis (such as oxalic acid and toilet cleaners) to prevent the boards from fading.

• Check once a year whether the screws are loose and whether the expansion gaps are blocked (timely clean up fallen leaves, sediment, etc. if any). If the gap sealing adhesive is aging, reapply the adhesive.

By following the above steps, the WPC can be installed firmly and durably while ensuring aesthetic appeal. Adjustments should be made to the details according to the actual situation of different scenarios (e.g., indoor vs. outdoor, dry vs. humid). For large - area installation (e.g., over 50㎡), it is recommended to draw an installation drawing in advance to clarify the keel spacing and the position of expansion gaps, so as to avoid on - site rework.