Title: High performance coatings for UK timber in exterior applications: Powder coating (231938)
Authors: Report commissioned from BRE
Full Report: Awaiting electronic version
The project intends to critically appraise the opportunity for utilising an established high performance coating technology for coating selected UK timber specimens to produce a high performance coated exterior wood product. The products under consideration for this technology would be fully factory finished and ready for installation as cladding, doors, garden buildings and garden furniture. The technology barriers will be identified and samples of UK timbers will be coated to provide test specimens for conducting the European Standard exterior wood coatings tests, to EN 927.
Powder coating is used to coat interior wood based products and other metallic and non-metallic surfaces. The technology offers tremendous savings as reduced processing times. From an uncoated board product to a coated product that can be packed and shipped the processing time can be as short as one or two minutes, a fraction of the processing time for conventional spray applied coatings. In addition the technology offers some interesting sustainability advantages through the use of no solvent technologies and improved durability of surfaces.
The potential outcome would be a high performance (long life, reduced maintenance) exterior coated wood technology using UK timber.
Interest in timber cladding for exterior uses is increasing in popularity, and it is necessary to ensure material fit for purpose in order to maintain and expand on this resurgent market. One possible area of interest is through the use of home-grown Sitka spruce – a readily available material with potential for adding value. Demonstration of different cladding designs using home-grown Sitka spruce. 2 years of moisture monitoring and condition assessment of cladding rigs.
In order for Sitka spruce to enter the exterior cladding market, it is necessary to demonstrate that the material is fit for purpose. Demonstration and product performance is important. Key field trials of UK material have been established during this project. The monitoring of these will continue under a monitoring contract (FG07/05) for the Forestry Commission.
The aim of the scoping study report is to highlight trends in the cladding market and how these may be applied to Sitka spruce. In general, UK grown timber (such as Sitka spruce) does not possess the attributes traditionally specified by UK designers for claddings when applying current evaluation criteria. This may be due either to timber quality or to the inherent properties of the timber. Through selection/sorting of timber and finger jointing (if needed), UK sawmills have the potential to supply good quality cladding material. Where superior performance is required, it may be possible for UK grown timbers (and particularly Sitka spruce) to gain a larger share of the cladding market by using some of the new treatment processes currently gaining favour throughout Europe.
The aim of the desktop study report is to provide guidance on the optimal techniques for cladding construction using Sitka spruce, and is intended as a continuation of work within this project from the Scoping Study (BRE report 211-547). This will be used in conjunction with benchmarking performance.