Common Timber Species for Traditional Sash Windows
A light weight timber is desirable for vertical sliding sash frames because they have to be counterbalanced. Accoya is recommended. Window sills (cills) should be durable and not liable to twisting or splitting. Hardwood is recommended.
Whilst wood price is a consideration, remember that the biggest cost comes in the manufacture & installation. At Sash Window Specialist we do not mark up premium timber and so you will only pay the difference of what the plank costs us. The differences in pricing on a finished bespoke joinery item is very reasonable, allowing you to select the right product for your project, ensuring a long lifetime of use.
The environmental benefits of timber
Wood is naturally beautiful and versatile and is one of the best ways to address climate change. It is renewable and abundant and as we transition to a low carbon economy, the advantages of wood are increasingly making it the material of choice for the environmentally conscious.
80 years of research resulted in Accoya, a high performance wood that exceed those of the best tropical hardwoods. Using nontoxic processes fast growing pine is structurally altered to produce a stable, very durable product.
A time proven durable softwood that is still popular today, however Douglas-Fir is a premium grade softwood which is reflected in the price. Grown around the world including USA, Canada, New Zealand. Other names include Oregon pine & British Columbian pine.
The most commonly encountered timber used in the construction of traditional windows in Europe, due to its continued popularity since the late seventeenth century. Know under many other names inc. Red Deal, Yellow Deal, Softwood, Scandinavian Pine, Scots Pine, Baltic Pine etc. Deal includes several varieties of pine, fir and spruce imported from Northern Europe.
The European Redwood available today is rapid grown in sustainable plantations but not to the same quality as the old growth timbers of yesteryear.
Meranti is variable in both colour and density as there are many sub-species of tree. It is a popular, affordable South East Asian hardwood used for manufacturing windows & doors. Often marketed as Luan or Philippine mahogany.
Occasionally used for the construction of sash windows in grand or public buildings where the figure of the grain is desirable. True Mahogany(Swietenia) is indigenous to the Americas but other species are often marketed as mahogany.
A common alternative to the more expensive Mahogany. Sourced from West Africa, often marketed as African Mahogany. Utile is a similar timber with a more intersting grain.
It can be difficult to obtain quality timber stocks (we only use certified sustainable sourced timbers ).
Needs no introduction. European or American.
A common timber in Australia
A soft aromatic timber usually selected for a stain finish. The wood is non-resinous & straight-grained.
Timber density is quoted by our suppliers as an average, however this can vary by 20% or more.
Vac Vac Treatment
Involves the application of organic preservatives to softwood timber under low pressure. The timber is placed in a vacuum chamber to remove air from the timber, water based preservative is then introduced, penetrating into the timber structure. A 2nd vacuum is employed to remove the excess preservative.
Effective for treating the sapwood of pine but not the denser heartwood, Douglas Fir or hardwoods. Untreated painted softwood joinery can last for decades but only if the paint coating is maintained in prime condition. Vac-Vac treatment offers some protection against rot if water does penetrate into the wood. Painters often report that this treatment can cause the paint to peel.
Acetylation Treatment – Accoya Modified Wood
Unlike pressure treatment, in which preservatives compounds are infused into wood, acetylation chemically modifies the wood. The process alters the cell structure of wood, improving its technical properties and making it much stronger and more durable resulting in better dimensional stability and decay resistance. Acetylation reduces moisture in the cell wall to the point where there isn’t enough left to support fungal or insect development.
Read the Accoya FAQ here