Measuring the wind suction capacity of plastics-based cladding using foil bag tests: A comparative study

•Wood-Plastic Composite (WPC) claddings were tested against wind suction.•Wind suction was simulated by inflated foil bags.•Mounting of panels was feasible by screws in slotted holes.•Tested specimens failed due to low fixation resistance.•Fiber-reinforcement and wall-thickness increases wind resistance of WPCs.•The product development of WPC cladding should focus on fixation mechanism.

Wood-plastic composites (WPC) represent a new generation of bio-based materials which have raised the interest of the building industry. Investigations of the performance of WPC cladding under wind suction demand an application-oriented approach. So far façade planners have not been able to obtain a satisfactory estimate of the structural resistance of WPC cladding. This study contains a comparison between two wood-fiber polypropylene-based WPC products (WPC-1; WPC-2) and two PVC-plastics cladding products not containing fibers (PVC-1; PVC-2). A non-standardized test was used to examine the wind resistance of cladding under varying fixation distances. Wind suction was simulated with reference to the EU guideline ETAG 034 and ASTM E 72 both recommending using inflated foil bags at the rear side of each test façade section. Panel deformations were measured at the test section's midspan. Local failure around a fixation device was investigated by microscopy analysis. It was found that WPC cladding failed due to edge cracking, whereas the PVC claddings failed due to pull-through of the fasteners. Product WPC-1 showed the lowest failure load at Fmax =3.80 kN/m2, whereas product WPC-2 reached failure loads exceeding 13.00 kN/m2. The resistances of both PVC cladding products were close to that of product WPC-1. The results confirm that the resistance of plastics-based cladding is governed by its fixation mechanism rather than its bending strength. Moreover, bio-fiber reinforcement did not necessarily differentiate the WPC cladding from the plastics-based cladding without fiber reinforcement in terms of wind load capacity.