Off site timber frame construction is now recognised as a good strategy for minimising waste through efficient manufacturing and design processes. Also known as Modern Methods of Construction (MMC), offsite construction has many distinct advantages. Benefits such as quality, shortened construction times, cost control, increases in quality and environmental credentials have led to MMC becoming adopted by the construction industry.
Off site timber construction can help to dramatically reduce the amount of on-site waste that is generated during the assembly and erection of a building.
The Role of Construction in Sustainable Development
The construction industry has a huge impact on everybody’s quality of life by contributing to sustainable development. The focus of sustainable development is on making improvements to the quality of life for everyone, while minimising the use of natural resources. This ensures that these natural resources are not consumed beyond the environments capacity to indefinitely supply these materials.
In fact, sustainable development is as old as humanity itself. Historically many cultures have identified the need to live harmoniously with nature, and to consume natural resources responsibly.
Off Site Timber Frames
In many parts of the world it is now understood that off site timber frames are a sustainable construction solution that lend themselves well to small buildings in all sectors. Timber frames are environmentally friendly in many ways. The timber itself is a product of sustainably managed forests. However, because the frames are assembled at the factory, there is no onsite waste. A significant amount of wasted timber can be generated through off cuts alone. Timber at the factory can be cut to ensure that waste is minimised. Any waste that is produced can then be used to produce lower grade timber products such as MDF and chip board. The amount of waste that is sent to landfill is negligible.
There is now legislation throughout EU member states that specifically requires contractors and developers to deal with waste efficiently. This is as cost effective as it is environmentally sound.
The thermo-efficient properties of wood make it a naturally ecologically sound building material. This is one of the reasons for its popularity in Scandinavian countries and other countries with colder climates such as Canada. The availability of the material has also historically made it an obvious choice.
However, increasing environmental credentials is not the only benefit. When timber frames are manufactured off site, they can be subjected to far more rigorous quality control procedures. Many manufacturers of timber frames within the EU use only the highest quality and certified materials. Typically only EU sustainably produced slow growing hardwoods are used. This minimises the environmental impact of the product, but it also ensures that the timber is both rigid and strong.
Timber frame construction also allows for floor cassettes and floor panels to be produced within a controlled environment. This means that the product can be tested on multiple occasions before it reaches the site. Because each element of the superstructure is checked so thoroughly to ensure accuracy, this enables rapid assembly and erection.
Timber frame construction has been an industry standard in Scandinavia and other Northern European countries. However, until recently, brick and block construction has been the traditional choice for residential dwellings in the UK.
Timber frame construction has become more common in the UK in recent years. It is now mainly used for residential single occupancy dwellings of 3 stories or less, small commercial buildings of under seven stories and small institutional buildings of under seven stories.
The United Kingdom’s timber frame market generally consists of three forms of assembly:
1, Stick build: This is where timber is pre-cut to length for joists, studs but assorted random lengths are also included for top plates, bottom plates and the sole. These are delivered to site as kits which are then assembled.
2, Panelised walls: This makes up a majority of timber frame construction in the UK. Pre-manufactured timber frame panels are delivered to site. Upon arrival they are ready for assembly to form both non-load bearing interior partition walls and structural load bearing walls. Panelised wall elements usually include features such as windows, doors, insulation, services, interior lining and exterior finishes.
3, Roof/floor cassettes: These are similar to the wall panels, only they are manufactured to a larger size that is suitable for floors and roofs. Floor boards, beams and the joists are included at the very least. Services, lining and insulation can also be added during the manufacturing process in more advanced systems.
Generally speaking, a huge advantage of timber frame structures is that no further modification of the elements is required during assembly and erection. However, when completing some interior patrician walls and external load bearing walls, it will be necessary to use various loose materials which often include:
- Nails and screws
- Plastic and timber shims
- Connecting plates and sole plates
- Breather membrane
- A vapour control layer (often polyethylene)
- Insulation (this is most likely to be mineral fibre)
The engineer is able to have an in depth and precise understanding and knowledge of materials that are required for the assembly of a structure. This is applicable both on site and at the factory. The elements are billable and therefore traceable and this, in turn, means that controlling any additional materials which may be sent to site is easier. This is highly advantageous in terms of eliminating the unnecessary waste of materials. The main operations on site are limited to the unloading of materials and assembly of floor, roof and wall panels to complete the structure. This is usually accomplished by nailing panels together and further modifications are not required. Most of the waste was generated during the manufacturing process at the factory.
The timber frame industry is typically responsible and pro-active when it comes to working with low carbon, sustainable and natural materials. However, the timber frame industry is able to offer significant benefits to the wider construction industry. Timber frames have a significant positive impact on the construction of buildings in terms of reducing the carbon footprint of structures and sustainability.
Many companies that manufacture timber frames constantly review their design and manufacturing processes. They also understand the need to invest in machinery and software which will optimise efficiency and reduce waste even further. Many even recycle their waste to produce other lower grade timber products at the factory.
This approach dramatically reduces the demand for raw materials as well as the amount of waste produced. Waste is segregated at the point of generation and the management of this waste can be combined with reusing and recycling materials. The production of zero waste to landfill is achievable.