The Application of Carcassing Timber and the Options Available
Carcassing timber is also referred to as structural timber because it is machined purposely for structural applications such as floor/ceiling joists, roof trusses and decking support.
Structural wood has many applications, which involve using it as background material. It is an integral part of any construction project, and the timber may be seen or not, depending on the plan. In most cases, the timber covers a substrate or is over clad, which is why it is not suitable for painting or other direct decoration. Spruce and pine are two of the softwoods used to create this type of timber. The engineering of the timber pieces depends on the specific applications. Structural timber comes in various forms to suit the different elements of construction.
Structural timber can be treated or not. The treated of timber applies extreme pressure to inject preservatives. Therefore, pressure-treated carcassing will last longer than the untreated variety because it has protection against rot and fungal decay. The strength of treated timber is another reason it has become a more popular choice than untreated wood. Due to its resistance to pest damage and moisture penetration, pressure-treated wood has low maintenance demands.
The pressure treatment of carcassing may vary from one manufacturer to another. Typically, customers get treated structural wood, depending on its uses. For example, timber that is used above ground and may be exposed to wetting such as decking supports is treated differently than wood that will stay permanently dry.
Carcassing timber can also vary on whether it is graded or not. Graded timber is suitable for load-bearing applications. The grading process divides timber into several classes, depending on their strengths. In the UK, customers can choose between C16, C24 and TR26 with the last two ranking higher in structure grade than C16. Graded timber is achieved by drying it in a kiln, which means that the excess moisture is removed. British carcassing is only able to achieve a C16 strength class because this type of wood grows in a warmer climate, which results in a faster growth rate than other kinds of structural wood. Machine grading requires the timber to undergo specific tests, including deflection under applied pressure. After the grading process, a manufacturer stamps the wood piece to indicate the producer, grade, condition and ID number. This stamp is what customers use to tell the timber quality.
When buying carcassing timber, be clear about the exact type of wood required for the application; is it treated or untreated, graded or ungraded.