High durable and fire performing WPC for ventilated façades

Main objective:

The aim of the project is the development and implementation of a ventilated façade system for its use in outdoor construction applications, based on high durability wood polymer composites, outstanding wooden aesthetic appearance and complying with the restrictive specifications defined by the Technical Building Code (TBC) for constructive elements, especially from the fire perspective. The new concept will imply a material recyclable and highly based on bio resources and recycled sources.

Scientific objectives:

  • Use of nanotechnology to improve mechanical and fire properties of composites. Treatment and optimisation of delamination or intercalation of nanoclays in the polymer via melt processing.

> Flexural stiffness and strength: at least 10% higher than current commercial WPCs. Even higher improvements have been observed in lab scale nanoclay reinforced WPCs.

> Reducing the quantity of traditional fire retardant (never halogenated) considering possible synergistic effects in at least a 50%. Scientific advances in fire performance  improvement of WPCs encourage this objective.

  • The required fire performance in a reaction to fire test will be Euroclass B-s3,d0 that means:

> B: lowest heat release rate for organic materials (FIGRA ≤ 120 Ws-1, LFS < edge of specimen andTHR600s ≤ 7.5 MJ)

> s3: No requirement for SMOGRA and TSP600s parameters of smoke.

> d0: No flaming droplets or particles.

  • WPCs with long fibres: stiffness and strength increase compared to traditional WPCs expected by 30%. Lab scale tests revealed that this improvement is possible be increasing fiber L/D ratio from 8.3 to 21.3.
  • WPCs with agricultural by-products (only for cost reduction in facing materials, not in profiling): reduction of strength compared to traditional WPCs not higher than 15%, due to lower L/D ratio of rice straw, wheat straw…. Lab tests conducted in one of the RTDs revealed that reductions in strength of 15-20% compared to wood fibre took place after the addition of agricultural by-products to different polymers.
  • Wood fibre modification will be also carried out to obtain hydrophobation to improve weatherability: Good surface aspect after 2000 hours in accelerated weathering conditions (UV light+water spray) and water absorbance and dimensional change of WPCs 30% lower than for traditional WPCs.


Industrial objectives:

  • Ventilated façade structures easy for assembly. Weight savings of 30-50% with respect to ceramic and stone.
  • Applications in building industry by providing adequate fire and durability properties
  • Development of a new façade system that will allow SMEs to compete with products of major quality and versatility in construction sector
  • Obtaining of a ventilated façade system that fulfil the following properties:

-          Watertightness of joints(EN 12865:2002)= 2.000A

-          Wind load resistance (ETAG 034)= 3000 Pa (Pressure) – 2.500 (Suction)

-          Airborne noise transmission (EN ISO 140-3:1995) = 40 dB

-          Thermal Behavior (EN ISO 10077-2:2008)= 2 W/m2·K

-          Reaction to fire (EN 13501-1)= B-s3,d0


Environmental objectives:

  • Environmental assessment of the composites must be better than that of current systems
  • Fully recyclable system (facing and structure)
  • Avoid the use of halogenated compounds due to the toxicity of generated gases during a fire
  • Development of eco-friendly products: Reduction of fossil fuel resources through the usage of biomass based fibers. Maximum of 40% of polymer (recycled origin) and natural fibre content equal or higher than 40%.

Social objectives:

  • This project allows sustainable development in the field of construction. It allows natural and recycling sources use together with an improvement in recyclability.
  • Better indoor quality due to the application of the ventilated façade system.