BSW manufacture FSC® Certified Timber Products in its UK mills,which means they are all made from professionally managed and sustainable sources.We take our environmental and social responsibility extremely seriously and we are committed to developing our business towards ecological, social and economic sustainability. Therefore we will only develop log supply from local and well managed sources that are FSC® certified.
Strength grading is undertaken primarily to provide timber of sufficient strength for a particular function,e.g.a floor joist or a roof truss. At the same time strength grading helps to ensure that both the design and the timber sizes specified are economical.
Softwoods are the most frequently-used timbers for loadbearing situations. In order to comply with the Building Regulations they must always be strength graded. BSW produce strength graded timber to specifications laid down in British Standards - BS4978 for visual grading and BS EN 14081 for machine grading. Timber is graded to strength classes. The most commonly specified grade for softwood carcassing is C16
Timber is loaded into treatment vessel and an initial vacuum applied which evacuates the timber cells of air. The cylinder is flooded under vacuum with wood preservative. Hydraulic pressure is applied,which forces the preservative deep into the structure of the timber. A final vacuum extracts the excess preservative solution,which is pumped back to storage.
Pressure treated timber is protected against fungal (rot) and insect attack to ensure a long service life.
BSW Timber utilise pressure treatment plants at our sawmills of which there are two main types.
Low Pressure - Low-pressure treatments are generally suitable for Timber Frame Studding and Roof Trusses where the hazard is not too great, and/or the wood species has some natural durability to begin with. You can often tell that the timber has been low pressure treated by its golden yellow colour, which is becoming the norm in the UK. It is suitable for Use Class 1, 2, 3.1.
High Pressure - High pressure treatments are based on a copper triazole technology. The copper is derived from recycled resources and is well known for its fungicidal and insecticidal properties. The triazoles (tebuconazole and propiconazole) are commonly used to protect many of the crops we eat. It is available in both green and brown treatments.
The timber is pushed into either batch or progressive kilns on railed bogies. The difference between the two types of kilns involves the static positioning of the stacks within the batch chambers,with the temperature and humidity changing through the drying cycle. In the progressive chamber the kiln packs move forward approximately every 5 hours through changing humidity and temperature.The sequence of changes is called a kiln schedule and the operators use different schedules for different sizes and species of wood.
- Dimensional stability and less risk of distortion
- Fungi and moulds cannot survive on dry timber
- Improved penetration of preservatives
- Smoother finish after machining
- Improved performance of finishes such as paints and stains
- Improved insulation
- Improved strength
- Lighter weight
To achieve the specification moisture content required for structural dry graded timber;and to supply dry pallet timber for the food and paper industry.
An automated process that uses heat and airflow in a controlled environment to remove moisture from sawn timber Timber is loaded into treatment vessel and an initial vacuum