Which timber – softwood or hardwood? What is Accoya?
Hardwood and softwood are historical terms and should be considered as general classifications. Softwood is a term used to describe timber from coniferous or needle-leaved trees and hardwood from deciduous and evergreen broad-leaved trees. The terminology, therefore, cannot be relied upon to describe the durability of the timber and there are notable exceptions such as balsa wood which is one of the lightest, least dense woods and is considered to be a hardwood. However, evergreens do tend to be less dense than deciduous trees and most hardwoods tend to be denser and are, therefore, sturdier.
American White Oak
American White Oak (Quercus Alba) is distinct from Western Europe Oak (Quercus Robur & Petraea). It is generally produced from a smaller log and is less durable than the European variety. However it is very popular for interior joinery, furniture and kitchens. Thinner boards are price competitive but this may change for boards over 50mm thick
Working Properties
· Good for nailing and screwing, although pre-boring is advisable (also reacts with Iron)
· Machines well
· Gluing results are variable
· Stains and polishes well
· Dries slowly and care is needed to avoid checking
· Can be susceptible to movement in performance
Physical Properties
· Heavy and hard
· Medium bending and crushing strength properties, but very good in steam bending Southern White Oak is heavier and harder
Durability
- Sapwood is moderately resistant to preservative treatment
- Heartwood is resistant to decay and extremely resistant to preservative treatment
European oak A hardwood, is one of the most durable timbers for exterior use. It can be treated with oil to preserve its blond appearance or can be left untreated and will gradually fade leaving it silver grey. Oak is one of the more expensive hardwoods and should not be painted. Utile and sapele are commonly used tropical hardwoods, suitable for exterior use and are cheaper than oak. These species can be painted or stained.
Redwood is the preferred softwood choice for exterior joinery and this can be coated with preservative prior to a paint finish to prolong the life of your joinery. Accoya is the latest high technology in wood. The Accoya process takes sustainable-sourced, fast growing softwoods and treats these in a non toxic process that ‘enables nature’ to create a durable and stable product.
