All About Wood
At Worktop Express®, we’re proud to supply the highest-quality wood worktops in the UK. Whether you opt for exotic zebrano or a solid oak worktop , we are confident you will be amazed by the attractiveness and durability of these wonderful timbers.
We’re committed to sourcing the finest solid wood for all of our products. As such, we’re the first to admit that we are geeks on anything wood-related! We’d like to share some of our enthusiasm with you in this article. Below you will find a short discussion on various characteristics of this fantastic, natural material, in which we hope to answer some of the questions you may have – though if you do not find the answers here, please don’t hesitate to contact us.
Structure and General Characteristics
From Seed to Sapling: Wood Growth and Grain Structure
Though a strip of timber looks pleasingly solid and coherent, wood is in fact made up of many tiny constituent parts. A network of miniscule, tube-like strands – through which food and water are passed – form the structure of the tree. After the wood is milled, an interesting variation in appearance can be noted, depending on the angle from which these tiny strands are viewed: for example, if you inspect the wood first from the top then from the side, you will note the contrast between the surface appearance and the cut ends.
You will probably be familiar with the sight of circular cross-sections of cut tree trunks: these are often displayed to demonstrate the lifetime of a tree. Rings pattern the surface of these cross-sections, radiating out from the centre of the tree. Each ring represents a year of growth.
Often the term ‘grain’ is used to refer to the delicate natural figuring of the wood used in furniture and kitchen worktops. This term usually connotes the appearance of these growth rings, which lend stunning natural variation to the wood’s surface.
Heartwood and Sapwood
As mentioned above, growth rings indicate the maturity of a tree. These are formed when new layers of the building blocks of the tree – the cellular tube-like strands – are added to the outside of the trunk as it grows. These outermost layers are responsible for conducting sap and become what is known as ‘sapwood’ while the inner cells forming the centre section of the trunk undergo a natural chemical transformation and die. These centre cells are referred to as ‘heartwood’. A more mature, dense form of timber, heartwood tends to be darker in colour when compared to the young, often lighter sapwood.
Hardwoods and Softwoods
Hardwoods come from angiosperm or monocotyledon trees, which are largely deciduous. Softwoods come from gymnosperms (coniferous) trees. Don’t be fooled by the name: though many hardwoods are indeed harder than softwoods, there are exceptions – the Caribbean Heart Pine is a notable example. By and large hardwoods offer the best materials for furniture manufacture, however, boasting a more consistently impressive range (though we’ve mentioned one instance of a sturdy softwood in the Caribbean Heart Pine, many species of pine that are widely sold are not particularly durable).
A popular test for the strength of wood is the Janka test, which measures the force required to propel a 0.44 inch steel ball into a given wood (to a depth of half its diameter). The measurement was originally taken in pounds-force [lbf] (though there are now alternatives ranging from kilograms-force [kgf] to newtons [N]). Tropical woods are often stronger than native timbers; Wenge, for example, measures approximately 1630 lbf where as European Oak measures 1320 (which is still impressive – many species of pine, a commonly used material for wooden furniture, measure as little as 690 lbf!)
Wood and the Environment
Wood is an extremely durable material, particularly when handled by specialists like Worktop Express® who are experienced in treating and preparing wood products. Even so, all wood will dent if extreme force is applied. Our worktops are robust and so a busy kitchen will present little cause for concern, providing the wood is maintained and oiled as we suggest.
No worries there, then…unless you are planning on putting on your dancing shoes! High heel shoes exert a huge amount of force – a person weighing 8 stone would exert nearly twenty times that amount of pressure when wearing high heels. Therefore, however compelled you are to leap onto your worktop and shimmy the night away, we would recommend resisting the temptation…
Environmental Effects: Wood Expansion and Contraction
Wood is a natural material and is structured in a particular formation (incorporating many tiny component parts); as such, it responds to its immediate environment. Changes in humidity will cause the minute tube-like strands of its construction to change in size. These alterations in environment cause the wood to absorb or lose moisture. Though this reaction will stabilise slightly to match the humidity of the surrounding environment, this is a gradual process that will continue. The size of the wood will change slightly as a result; shrinking when moisture is lost and expanding when absorbed.
For this reason, we advise customers to leave an expansion gap of 3-4mm between worktops and any adjacent walls. In this instance, we also recommend that our customers purchase an upstand. Opting for an upstand has two main benefits: the expansion gap is covered by a matching piece of solid timber, allowing the worktop to merge seamlessly with the wall; moreover, an upstand can prevent any moisture forming behind the worktop.
Heat also has an effect on this natural material. As such, we advise allowing a minimum gap of 30mm between your worktop and any source of constant heat (an Aga, for example). For protection against high temperatures, we supply end caps for our worktops (please see our article on end caps).
Wood and Moisture — don’t panic!
As mentioned above, changes in moisture have an effect on wood; however this can be easily combated by prompt action. Provided that any spillages are not left sitting on your worktop you will not have any problems. Wipe any such pools of liquid up as quickly as possible using a damp (not wet) cloth.
Wood Colour Variation
The timber will vary in hue due to natural occurrences in its development, and so colour variation cannot be wholly avoided in wood furniture – in fact, it is an attractive and characterful natural feature. Wood is a natural product and some degree of colour variation is inevitable.
Your wood worktop may also change in colour over time. This occurrence varies from species to species and is due to oxidation and UV light (sunlight also tends to accelerate the oxidation process). For most species this has the effect of a gradual, attractive deepening of the original colour. In other cases the colour changes dramatically and quickly: a notable example is the Iroko timber, which matures rapidly from yellow to a rich bronze (the bronze colour is what you would expect from Iroko furniture and thus the timber is advertised on the basis of the shade it becomes).
All these quirks can be enjoyed when incorporating this versatile natural material into your home, and will only increase the unique character and timeless appeal of your wooden worktop.