Oak is the most commonly used native Hardwood in the UK, mainly out of tradition – it was frequently used in centuries past for several reasons – the dense hard wood being very durable to moisture makes it a good building material and the difficult to dent timber means it is good for flooring and hard-wearing tabletops. However its main reason for use before the age of efficient saws and sawmills was its ability to be cleft, that is split into rough boards down the length of the grain with wedges, then smoothed flat with planes or adzes for furniture and flooring. The resultant cleft timber would always follow the grain perfectly, revealing the silvery medullary rays on the face and the bonus of such boards being that they are very stable with little shrinkage and warping potential. Boards produced these days at a sawmill with the same silver rays effect are called ‘quarter sawn’ and have a higher value than ‘crown cut’ boards, and usefully any wood type / species cut quarter sawn will be very much more stable, not just oak.
Very large diameter old growth UK oaks cut on the quarter can yield very fine wide boards of stable timber showing a richly coloured board with attractive strong presence of silver medullary rays and often a ripple or flame pattern.
Oak is not, however, an easy timber to work as it blunts tools quickly and is so hard it is difficult to sand smooth. The edges splinter easily so gloves are often wise when handling oak. Boards of any thickness can sometimes show patchy colour in the core, possibly a side effect of the slow seasoning process. Our boards are given 2 years per inch/25mm of board thickness to season. Oak generally has a large movement in service so will warp/twist/cup/bow readily with small changes in moisture (far less so with quarter sawn) and ends will split / check if boards are put too near to high heat sources.
All forms of oak take polish well and as the timber is so naturally dense and oily, polishes do not soak in far and so not many coats are required to fill the grain. Needless to say a Danish oil finish compliments oak well. The sapwood – the paler parts near the bark – is not durable, or strong and is very absorbent of polish and stain. It can still be used in rustic waney edge projects but will take a lot more polish than the much denser heartwood.
If staining oak, an old tradition is to ‘fume’ it using a saucer of ammonia in a plastic ‘tent’ or sealed box. Different timings produce different shades of brown, depending on the amount of natural tannin in the oak being used. It is generally, however, a more even and natural looking stain to any painted on type.