How Off-site Manufacturing Can Reduce Waste in the Construction Process

Research carried out by WRAP has stated that off-site construction generates up to 80 per cent less waste compared to site-based building methods.  This section looks at how Portakabin has reduced the volume of waste sent to landfill by 50 per cent in three years.

Design

• Good design and engineering waste-generating operations out of the manufacturing process from the outset is critical.  Examples include:

- Intelligent modular design, which maximises the use of standard width materials and minimises the amount of cutting to fit. 
- Door and window cut outs from insulated wall panels in Portakabin products are re-used for floor insulation in other products.
- The composition of polyurethane insulating foam has been changed, which has resulted in a 10 per cent reduction in material consumption.
- Steel beams are supplied to the factory in the precise length required for a specific module size, eliminating the need for disposing of off-cuts.
- Particle board used for floors is pre-sized for the Portakabin modules.  There is no  trimming to size or particle board waste, and the working environment in the factory is greatly improved as there are no wood particles or dust generated.

• The Portakabin off-site system incorporates a base that is integral to the module and therefore requires simplified foundations.  This in turn reduces the amount of waste sent to landfill or for redistribution on each site.

The Off-site Manufacturing Process

• Suppliers of low value, high volume materials, such as adhesives and fastenings, deliver direct to the production line.  This eliminates any packaging that would otherwise need to be disposed of.
• Wood chips generated in the joinery operations are collected in special trailers and sold.

Factory versus Site

• A factory has a better infrastructure than a construction site.  The Portakabin manufacturing centre is equipped with extensive lifting facilities, which means materials can be handled in larger and more appropriate sizes than on a building site.
• Conditions in a purpose-designed manufacturing facility are significantly improved compared to a building site that is exposed to the elements.  Skilled staff work at a constant temperature of around 16 degrees, without being encumbered by heavy clothing, which helps to ensure consistently high build quality.  On a building site, operatives can get wet and cold, which decreases their dexterity.  This has a negative impact on materials wastage, product damage and segregation for recycling.
• Advanced CNC cutting machines are used in the production of steel and timber module components, improving accuracy and reducing waste.
• The volume of material wasted through damage and deterioration is significantly reduced with off-site construction.  Any storage is under cover and in controlled factory conditions, and operatives are not subcontracted labour but are permanently employed and highly skilled and trained.

Recycling Waste

• The Portakabin Group, recycles 65 per cent of waste generated in the off-site manufacturing process.
• Staff training and instilling the discipline to recycle is key and is ongoing in order to maintain the waste streams.  In a controlled factory environment, segregation for recycling at source, using colour-coded skips, is much easier than on a building site. Portakabin has established waste management teams, consisting of a production manager and waste contractor or partner.  A permanent trainer is in post and refresher courses in waste segregation are held at regular intervals. 
• Pallets used throughout the manufacturing process are all recycled through the supply chain.