Specifying efficient use of materials and considering their impact from manufacture to disposal.
Reuse and recycling
Many building materials can be reused or recycled.
The ability to reuse and recycle materials salvaged from demolition and building sites for reuse and recycling depends on:
- local recycling facilities
- market demand
- quality and condition of materials and components
- time available for salvage
- emphasis put on reuse and recycling.
The BRANZ REBRI website has a recycling directory to help locate recycling and waste management organisations
On this page:
- reuse/recycling from construction sites
- reuse/recycling from deconstruction/demolition sites
- hazardous materials
- requirements for recycled or reused materials.
Reuse/recycling from construction sites
Materials that can generally be recycled from construction sites include:
- steel from reinforcing, wire, containers, and so on
- concrete, which can be broken down and recycled as base course in driveways and footpaths
- plastics – grade 1 (PET) and 2 (HDPE)
- paper and cardboard
- untreated timber, which can be used as firewood or mulched
- paint. A number of manufacturers/retailers take back unwanted paint and paint containers.
Reuse/recycling from deconstruction/demolition sites
Materials that can generally be recycled from deconstruction/demolition sites include:
- siteworks and vegetation – asphalt paving, chain link fencing, timber fencing, trees
- concrete – in situ and precast concrete
- masonry – concrete blocks and decorative concrete, paving stones, bricks,
- metals – reinforcing steel (rebar), structural steel, steel roofing including flashings and spouting, zinc roofing, interior metal wall studs, cast iron, aluminium, copper including flashings, spouting, claddings and pipework, lead, electrical, plumbing fixtures
- timber – hardwood flooring, laminated beams, truss joists, treated and untreated timbers/posts, joinery, untreated timber generally, engineered timber panels
- terracotta tiles
- electrical wiring
- wool carpet
- plastics – grade 1 (PET) and 2 (HDPE).
Components that can readily be reused include:
- timber – hardwood flooring, weatherboards, laminated beams, truss joists, treated and untreated framing, timbers/posts, New Zealand native timber components
- thermal insulation – fibreglass, wool and polyester insulation, polystyrene sheets
- carpet and carpet tiles
- plumbing fixtures – baths, sinks, toilets, taps, service equipment, hot water heaters
- electrical fittings – light fittings, switches, thermostats
- linings and finishings – architraves, skirtings, wood panelling, specialty wood fittings, joinery
- doors and windows – metal and timber doors, mechanical closures, panic hardware, aluminium windows, steel windows, sealed glass units, unframed glass mirrors, store fronts, skylights, glass from windows and doors, timber and metal from frames
- clay and concrete roof tiles
- metal wall and roof claddings
- PVC and metal spouting.
Hazardous materials must be disposed of appropriately. Check the requirements for removal and disposal of hazardous waste for your local area.
Hazardous wastes from the demolition of buildings may include:
- fluorescent light ballasts manufactured before 1978 – contain PCBs
- fluorescent lamps – contain mercury
- refrigeration and air conditioning equipment – contain refrigerants made using CFCs
- batteries – contain lead, mercury and acid
- roof and wall claddings, pipe insulation, some vinyl flooring, textured ceilings and roofing membrane sheets containing asbestos fibres.Asbestos can cause very serious health problems and its removal is controlled by law. See the page on Asbestos for more information.
- lead or materials that contain lead such as flashings, paint, bath and basin wastes.
When cleaning up, materials such as cement, sand, paint and other liquids and solvents, must not be released into the stormwater or sewerage disposal systems. This should be included in the demolition specification.
Requirements for recycled or reused materials
The BRANZ REBRI website has a Resource Routing Calculator that helps to calculate the economic value of sending different waste streams to landfill or to reclamation facilities. Factors include the:
- cost of transport
- cost of skip hire
- value of material
- weight/amount of material
- amount of contaminants.
Every market has its own specifications for recycled or reusable materials. Obtain specifications from the recycling operators before starting deconstruction so you know what to save and how to save it. You should find out:
- material type
- acceptable and unacceptable levels of contamination
- acceptable and unacceptable levels of damage
- quantities accepted
- transportation requirements
- required documentation including waste tracking forms
- sorting and handling requirements for each material type.
Things to check for concrete
- Types of concrete and rubble accepted.
- Size of concrete pieces.
- Amount of preprocessing.
- Acceptable levels of bricks and tiles.
- Acceptable amount of contamination from materials such as glass, metal, soil.
Some concretes products are too hard-wearing on crushing machines and some concretes are too soft to meet reuse specifications after crushing, so will not be accepted by operators.
Things to check for metal
- Types of metal accepted.
- Contamination tolerances from materials such as plastics and leftover product in containers.
Things to check for plasterboard
- New Zealand currently has no facilities for recycling plasterboard back into plasterboard.
- There are opportunities for use of off-cuts.
- Some composting facilities accept plasterboard – the gypsum content acts as a soil improver.
Things to check for timber
- Types of timber acceptable (for example, treated, native, untreated).
- Minimum and maximum sizes of board and lengths of timber.
- Minimum and maximum quantities.
- Contamination tolerances from materials such as nails, paint, concrete.
- Any preprocessing requirements such as sorting or grading.
- How timber is to be received (for example, loose, stacked in containers or on pallets).
Updated: 25 May 2020