Weatherboarding (also referred to as cladding) can provide a beautiful finish to your timber frame. There are numerous options of material, profile and finish to choose from and therefore a wide variety of different combinations, each with its individual style. The aesthetic considerations are probably the first thing to think about. However, there are also differences in cost, durability and fitting.
Weatherboarding on an extension can provide an exciting contrast to the finish of the main house which in some cases can break up large visual expanses. Planners often like to see this. It is possible to achieve a classic traditional appearance, rustic for outbuildings or crisp and contemporary for more architectural situations. As with any external timber, untreated weatherboarding will gradually silver down under the action of sunlight. Despite starting with very different colours, the oxidation process ultimately renders most timbers to a very similar appearance making them hard to tell apart.
Carpenter Oak tend to favour the use of rough sawn boarding which we use in its fresh sawn (unseasoned) state. Oak, Larch and Western Red Cedar are the main three timbers used, although Elm and Chestnut are also available. Each is naturally durable and offer good lifespans. The most durable are Oak and Cedar. However, the thickness of the board has a significant influence on how long it will last. The thicker the board, the more stable it will be, meaning the detailing will hold its integrity. Thicker boards are less affected by the degrading effect of the weather over time.
Fresh sawn boards are cheaper than machined and processed timber and provide a simple, classic finish. None of these timbers needs further treatment, and we generally use these with a rough sawn finish. Simple lapped boarding has a real charm to it: the slight variations in section and width mean it is easy on the eye and gives a relaxed, informal, timeless look. A new house finished with rough sawn boarding can mellow and blend into the landscape with ease and within a year can look as if it has always been there.
Painted weatherboarding also has a rich history in many countries and can be the perfect style for some environments. You may be better off using a machined board, as they are usually already dry and take a finish more easily. They are available in a variety of profiles. Fresh sawn boards will need a few months to dry before painting or colour-washing.
Machined boarding is usually more expensive but is dry from the word go and therefore more stable. It offers consistent sections which give it a crisper appearance and make the fitting and detailing more comfortable.
There are newer products on the market such as ‘Thermowood’ which claim to offer increased levels of stability, insulation and resistance to insect attack and rot. Manufacturers achieve these aspects by heating the timber to high temperature – a process which denatures the timber, changing its cellular and chemical characteristics, making it impossible for insects and fungi to use it as nourishment. This process makes it extremely durable.
The research into heat treatment has been going on since the 1930s with techniques perfected in Finland in the 1990s. The characteristically dark heat treated wood is perfect for architecturally designed houses and contemporary finishes. It is available (among others) in ash, poplar, and a range of high-quality Scandinavian redwoods.