You can learn more about softwood carcassing timber and how it is graded by our professional timber grading team here.
Softwood Carcassing Service Life
All our softwood carcassing is supplied to C24 grade and is impregnated with Vacsol Aqua preservative using a double vacuum pressure process. This treatment gives a service life of 60 years. As with all timber treatments, if you cut and machine rafters after treatment has been done, then this affects the service life of the treatment.
We make sure that the service life is maintained by using the correct end grain treatment on all cuts before it leaves our factory. This ensures that your building has maximum protection.
What is Carcassing Timber?
Carcassing timber is softwood that has been kiln-dried and then graded according to its strength quality of C16 or C24, before being identified with the relevant grading mark.
Carcassing timber is often used for structural applications, such as floor joists, rafters and studwork.
How is Timber Graded?
The grades for carcassing timber, including C16 and C24, are set out by the British Standards Institution in the BS5258 compendium of codes. When grading the timber against these guidelines, various measurements are considered in order to assess the strength of the wood.
Factors taken into account include:
- Knots
- Splits along the grain
- The slope of the grain
- Woodworm holes
What is C16 and C24 Timber?
C16 and C24 are two of the most commonly used grades of timber. The C stands for conifer, the type of tree that the timber comes from, while the 16 and 24 refer to the strength grade.
Both grades are used in a variety of structural applications, including:
- Rafters
- Floor joists
- Studwork for partition walls
- Formwork
- Shuttering
- More beyond this
The different grades are suited to different loads.
What is C16 Timber?
C16 timber is one of the most popular types of timber in the UK and is utilised in a wide range of applications. These will typically be internal projects such as walls, floor, and roof joists. As well as offering strength, compression and density (qualities that are widely sought after in the construction industry), C16 timber is also usually very cost-effective.
The reason that C16 timber is more cost-effective than other grades of timber is that it can have some defects. These include grain deviations, which can impact the strength of the timber, as well as cosmetic marks such as sap stains and uneven surfaces.
What is C24 Timber?
C24 timber is one of the highest quality types of timber available.
Similar to C16 timber, it is also kiln-dried to reduce the moisture content, it typically has fewer defects, in terms of both characteristics and appearance. This makes it stronger and more resilient. It also looks better, making it a popular choice for applications that are going to be visible.
Due to its quality, the cost of C24 timber is usually higher than C16 timber.
What’s the Difference Between C16 and C24 Timber?
There are several differences between C16 and C24 timber:
Quality
Although both C16 and C24 are strong, durable, and used widely throughout the construction industry, C24 timber offers premium quality.
Appearance
C16 timber can have some defects that impact the overall appearance. C24 graded timber, on the other hand, has fewer visible defects and a more uniform appearance. This makes it the preferred choice for projects where the timber will be visible within.
Strength
Both C16 and C24 timbers are strong enough to handle the demands of construction applications. However, C24 timber is the stronger of the two, meaning it tends to be the material of choice for larger projects or those where strength is essential.
Cost
If you’re working to a budget, C16 timber is typically more cost-effective because it is usually produced in the UK. C24 grade, on the other hand, can only be achieved by importing the timber from areas where the climate forces a slower growth rate. This increases the cost.
Treatment to Our Softwood Weatherboard
All our softwood weatherboard is treated with Axil 3000P, which is a water-based wood preservative.
