Reducing waste (through design, off site construction, reuse etc.) will reduce the total cost of disposal, as will finding alternative end-markets to which unwanted materials can be sold or donated. For example donations of furniture to social enterprises, selling reclaimed products to a salvage yard and operating an in-house "resale" of unused materials to the next project.
If the design team has adopted solutions such as off site construction and in situ reuse, there will be a signficant cut in waste volumes, so it is important to communicate this within the Site Waste Management Plan and project specification at the ITT stage to avoid contractors over-pricing for the "risk" of typical waste arisings.
The client can encourage cost savings on waste disposal by:
- Adopting minimum and stretch recovery rates as requirements in the Project Brief and procurement documents;
- Agreeing waste disposal as a separate cost rather than accepting a fixed price that is bundled into the preliminaries; and
- Asking their design team to forecast waste quantities (after allowing for waste reduction actions), so that contractors can price their waste managment more keenly.
Details of potential cost savings in design and in construction are shown below:
WRAP recommends focusing efforts on five main areas as outlined and explained in the Designing out Waste Guidance.
- At an early design stage select alternative design solutions with lower materials use, greater reuse and lower waste (including Off Site Construction); and
- At a later design stage identify ways of reducing wastage rates within the chosen design, e.g. standardising specifications and/or simplifiying the design to minimise the amount of off-cut waste.
Some of the largest opportunties to reduce waste on site include:
- Ensuring there is an effective strategy for delivery, handling and storage of materials, e.g. a Material Logistics Plan;
- Providing site training on the appropriate use of materials (to avoid unnecessary off cuts and encourage their re-use as appropriate); and
- Targeting packaging either through reduction at source or through take back agreements.
All these actions should be recorded in the Site Waste Management Plan, starting from the early design stage. In England, the SWMP Regulations 2008 require the contractor and client to include in the final SWMP an estimate of the cost savings that have been achieved by completing and implementing the plan.
While reducing total waste can be more effective on large projects, the design team and contractor should still investigate the following on small projects:
- Choosing to refurbish instead of replacing structures or components;
- Avoiding unnecessary excavation and strip-out;
- Reusing construction, demolition and excavation materials available on site;
- Selecting pre-fabricated components;
- Reducing wastage allowances on major materials (e.g. by improving materials storage, agreeing just-in-time delivery and adjusting floor-to-ceiling heights to reduce the expected wastage rate of plasterboard from say 20% to 10%); and
- Select materials and components with low maintenance requirements, long in-service life and easy refurbishment.
Further guidance on good practice in small projects can be found in WRAP's guide to Reducing waste in smaller construction and refurbishment projects and programmes of minor works (803 kb).