BWF members such as yourselves frequently use our Member and Technical Helplines for assistance on a wide range of Employment, Health and Safety, Contractual and Technical issues. We’re putting up a frequently asked question every Tuesday in order to help members and illustrate the type of advice we are able to provide. If you have any questions that you would like to see featured, we would be happy to assist. This question and many others like it can be found in our Question Centre. If you want further advice on any of the issues, don’t hesitate to ring the helpline or browse our extensive publications library, which includes our information on Installation, Building Regulations and Maintenance. This week: My Customers Are Complaining About Changes In The Colour of Wood In My Products. What Do I Do? A subject that crops up occasionally is the colour of wood. Sometimes a customer wants to know why a timber or joinery item has changed colour or it is not what they were expecting immediately after installation. The colour of wood can range from almost white down to ebony black and is produced by natural colouring material in the timber. Some of these colouring materials are part of the polymeric substances which make up the timber so that they are not readily extracted by solvents. However, many of the natural dyes are readily destroyed by strong sunlight and this can be prevented by incorporating an ultraviolet-absorbing substance in the coating applied to the wood. Some timbers contain water soluble colouring matter and timbers such as afzelia, ayan and idigbo tend to suffer from discolouration when subjected to dampness. Timbers which contain free tannin are stained when brought into contact with iron and iron salts. Timbers affected in this way include: oak, sweet chestnut, walnut, makore, afrormosia, idigbo and western red cedar. Metal fastenings used in conjunction with these timbers therefore need to be specified using either galvanized or non-ferrous metals. Alkalis turn timber brown or yellowish-brown, while acids can stain woods such as walnut, sycamore, maple, agba and sapele pink. Another aspect that customers frequently contact the technical team about is why some joinery items do not appear to be uniform in colour, for example, the case of a meranti door where the stiles and rails (and panels) appeared to be vastly different in colour from each other. With this it appears that the customer has not really appreciated the beauty of timber with the grain variations and also possibly not stood back from the door to appreciate the item as a whole. As the stiles and rails are at right angles to one another the angle of reflectance of the light from the grain is completely different and so will present the wood as contrasting darker and lighter shades. The customer was eventually persuaded to accept the door.