Oak remains the most iconic of British hardwoods, but how does English oak fare against imported oak, and do designers and specifiers fully understand and appreciate the available choices and advantages of English oak over imported timber? Tom Barnes of Vastern Timber explains.
Oak from English forests has been used in construction for centuries, and original oak beams continue to support structures more than 500 years old. The traditional popularity of English oak can largely be explained by the availability of the trees and durability of the wood. As a natural building material, oak is extremely hard to destroy; large sections will resist fires intense enough to melt metal and will flex to accommodate the natural movements of a building.
A third of Vastern Timber’s business is in supplying oak beams, and the company has a particular passion for English oak (Quercus robur) which is considered to be the strongest of the oaks because it has a more interlocking grain than oak from continental Europe, which is characteristically more mild and straight grained.
Oak beams are usually cut from trees between 90 and 120 years old, ideally felled during the winter when the sap is down. The beams for construction tend to be fresh sawn or ‘green’, which means that they are in fact wet, and while this is of concern to many architects because of oak’s natural tendency to shrink and split, it is the ideal way to use the timber. The alternative, dry oak, is very hard and therefore more difficult to work.
There are two main sources for structural oak – the UK and France. While imported oak can often be cheaper, there is a sustainability price to pay if the wood is imported. There is also a great deal of difference in design flexibility. Local British sawmills are easy to access, and as well as the option to inspect timber and cuts before choosing, the designer will benefit from more flexibility in cuts from their local sawmill, especially curved and shaped wood.
But it is the issue of sustainability which ultimately dictates that English oak is the better and more responsible choice. With growing momentum of the Grown In Britain movement that aims to promote the benefits of British grown timber, as well as supporting better management of native forests and woodlands, the reality for architects and designers specifying structural oak is that there are more good reasons to buy British than not to.