Engineered Timber A variety of products is available where the timber’s natural characteristics are improved by the careful combination of different timber sections. One of the most well-known examples is plywood, where several thin veneers of timber are bonded together. The grain of each section runs at right angles to its neighbour, allowing for strong, large, thin and flat boards in the manufacturing process. More recently, timber sections have been strategically bonded together where, whilst the grain direction is parallel, between adjacent ‘laminations’, the natural ‘cupping’ of the timber section is reversed. This helps to ‘neutralise’ any effects of dimensional changes due to climate fluctuations; each lamination is affected in the usual way, but its movement is resisted by its neighbours tending to move in the opposite direction. These characteristics are of particular importance in the production of windows and doors which are naturally exposed to climate conditions, but where dimensional stability is important for a reliable operation. Hardwood Oak is commonly regarded as the ‘timber of choice’ for a wide variety of hardwood applications. In fact, there are two distinct varieties in common use: Sapele is a reddish-brown timber and a member of the mahogany family. Red Grandis is a similar material to Sapele, but as less dense, it can offer advantages where weight is an issue. Black American Walnut is dark in appearance and has a distinctive ‘burr’ type grain. It is normally used for interior joinery such as staircases, flooring and fitted furniture, where a more ‘striking’ finished appearance is required. American Tulipwood, by contrast, is a light-coloured (almost white), open-grained hardwood; easily machined, stable and capable of achieving a fine finish and is ideal for painted interior joinery. Softwood Douglas Fir is the traditional softwood for British external and structural joinery. Redwood, despite its name, is a yellow-white timber.