Comparing wood–polymer composites with solid wood: the case of sustainability of terrace flooring

Due to emerging markets for environmentally benign products there is an increasing need for reliable evaluation and transparent information. In this regard, products made of natural materials, like the wood polymer composites (WPC) examined in this study, have to meet particularly high performance levels. To be economically successful they have to prove themselves as products with lower environmental impact compared to alternatives. The required information can be provided by a comparative life cycle assessment (LCA). The purpose of the study at hand is to assess the competitiveness of WPC in environmental terms in its main market of terrace floorings. In this LCA study, two different types of WPC, differing in composition and geometry are compared to two wood decking materials, consisting either of bilinga (tropical wood) or of pressure-impregnated pine (regional wood) with an identical geometry. The functional unit is 1 m2 covered terrace. Process steps identical in all products process chains are excluded. The impact assessment is done with a standardized method for different impact categories. Cumulated energy demand (CED) is shown as separate inventory. Under the assumption of identical lifespans, results show that for all impact categories the terrace made of pine is the most environmentally benign one. Compared to tropical wood WPC is mostly advantageous. WPC terraces may show in particular higher lifespans than wooden terraces and could furthermore be recycled as well. Both would lead to improvements which could result in comparable environmental impacts of WPC and pine wood.