The timber used traditionally for softwood joinery in the UK is redwood (Pinus sylvestris). In the past its ready availability in the desired sizes and quality and its durability in service encouraged little competition. However, the past decade has seen some erosion of this position, particularly through the increased proportion of sapwood in redwood supplies. Since the sapwood is less durable than the heartwood, premature decay in external joinery became an all too familiar occurrence, and preservative treatment was widely adopted. More recently concern has been expressed by the BWMA that should the supply position on redwood deteriorate further, shortages could develop in redwood of the sizes and quality required for joinery. In this event it could become necessary to employ other timbers to make up the short fall. One timber for which adequate supplies can be foreseen is whitewood. Whitewood is the common name for spruce of European or Scandinavian origin, the timber being composed mainly of Picea abies. It is less dense than redwood, but its mechanical and working properties are quite suitable for joinery purposes. Indeed, whitewood is accepted as a timber for internal joinery, on the basis of its general characteristics, but its low natural durability and the difficulty in applying preservatives to an effective depth has militated against its use externally. In consequence the previous use of whitewood in external joinery in the UK is too limited to provide any useful service data on its durability in this situation. It is against this background that PRL have been asked to give their views on the anticipated behaviour of whitewood and on any preservation requirements. One European country which has used whitewood extensively in external joinery since 1945 is Holland. In a climate similar to our own they have experienced decay problems analogous to those encountered in the UK with redwood. To deal with this situation the Dutch authorities have found it necessary to introduce requirements both in relation to design and to pre-treatment with preservatives.

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