Why do your WPC decking boards crack?

A critical root cause lies in the inherent quality of the material itself.

To cut costs, some manufacturers raise the proportion of wood flour excessively, which prevents the plastic matrix from fully encapsulating wood fibers. This leads to reduced material toughness and increased brittleness — a typical defect known as ‌under-plasticization‌. The plasticization quality directly determines the extruded board's mechanical strength, water absorption rate and crack resistance.

2.Using low-quality plastic that has been recycled multiple times and severely aged, this kind of inferior material features poor UV resistance and is prone to aging and brittle cracking.

3.As wood fibers and plastics are inherently incompatible, insufficient compatibilizer addition will result in weak interfacial bonding between wood powder and polymer matrix. Without proper control, micro-delamination is highly likely to occur under mechanical stress or drastic temperature shifts, which severely undermines the long-term durability of WPC products.

We Utimber WPC decking board , enforce rigorous quality oversight from the very first stage of production, with a firm focus on raw material quality to build a rock-solid foundation for all our products.

All core substrates are made from high-purity virgin HDPE and stabilized-grade wood fibers, fundamentally eliminating the inherent defects of ordinary WPC products — easy brittleness, premature aging and rapid color fading — right at the source.

Every batch of incoming raw materials is ‌mandatorily tested‌ for moisture content, ash content and particle size. Unqualified materials are strictly barred from production. Our scientifically calibrated plastic-wood fiber ratio perfectly balances the natural wood texture and the waterproof, durable properties of plastic.

Every batch of orders must go through a mandatory boiling water test: immerse the samples in 98℃ constant-temperature hot water for 72 consecutive hours. After the test, inspect all exterior surfaces one by one, with focused verification on cross-section areas, to confirm no abnormalities such as cracking occur.

By choosing ‌UTIMBER‌, you are no longer purchasing an asset that demands massive extra maintenance efforts, but a space that purely serves your daily life. We eliminate all cracking and aging risks of inferior boards right from the source, delivering superior long-term stability and a worry-free, hassle-free full-lifecycle user experience.