Designing for waste minimisation

The initial consultation with the client is a great opportunity to discuss the importance of waste minimisation.

Here are some tips for getting your client on board!

• chat about the environmental impacts of construction, and the benefits of minimising waste for the environment and how it can reduce project costs and enhance the reputation of our project
• share some success stories from similar projects or previous clients
• go over the potential cost savings. For example, how using durable materials could save your client money in repairs and maintenance over time
• emphasise the importance of spending time on a detailed design, as this will help create a building that both meets the client’s needs and minimise waste

The first conversations with your client provide an opportunity to shape and influence their ideas.

Here are a few topics to consider when discussing construction plans with your client:

• incorporating salvaged building materials can add character and reduce the need for new materials
• using durable materials require less maintenance, which can save your client time and money in the long run
• including spaces for waste sorting and storage in the building plans
• designing with flexibility in mind to ensure the building is functional for future needs

When forming your team, consider the following:

• involving design professionals who are interested in sustainability especially waste minimisation
• if possible, include the main contractor and key subcontractors in the design team, or another team member with construction expertise
• consider including suppliers in the team, their expertise can help ensure materials are used efficiently, reducing cost, waste, and labour
• establish clear roles, responsibilities and expectations for waste reduction
• keep the conversation going throughout the process, make waste minimisation a regular topic at toolbox talks and review meetings

• as a team, explore ways to reduce waste throughout the building’s lifecycle, from design to post-occupancy. The more specific your goals are, the better
• it is important to get everyone on board with your waste reduction goals

By working together and staying informed, your team can look for opportunities to improve, and make a positive impact on construction waste.

Once your team has been put together, and everyone is on board, it is good to start strategically planning for how you will reduce construction waste. Here are some important things you should know:

• if you’re planning on using second-hand materials, reach out to salvage dealers, material reuse website like Mutu or CivilShare, or your local council for material exchange options
• find out about local reuse, recycling and recovery options for construction and demolition waste by using the BRANZ Resource recovery map. You can also contact your city or district council for further guidance.
• look into new building practices and materials that could help reduce waste.
• stay on top of product information and changes in material standards by attending trade information sessions, such as toolbox talks hosting by your local suppliers
• create a list of preferred specifications that prioritises materials with recyclable content, and/or recyclable packaging and/or are a part of a product stewardship scheme

• aim to minimise the removal of vegetation and soil, which often ends up as solid waste
• protect specimen trees and areas of biodiversity and special ecological significance
• look for opportunities to compost materials and think about how much/what type of materials your project will generate
• maintain the integrity of the site by designing to minimise cut and fill
• design according to the contours of the land to ensure minimal impact upon soil excavation. For example, sloping sites may lend themselves to split-level design while level sites are appropriate for slab floors
• remember to keep and replace topsoil after construction to preserve the nutrients in the soil and reduce the need to transport excess soil elsewhere

• before choosing to redevelop a brownfield site check with your local and district council on any specific planning requirements they might have
• when advising clients on the best options for redevelopment, consider the generation of waste and associated costs
• consider reusing existing buildings, they can be relocated and re-erected. Renovating a structurally sound building is usually more material efficient than starting from scratch
• if you are thinking about relocating a building, keep in mind it will require the same design considerations as a new build. Check the Building Code and Building Act, as a relocated building must comply will all current standards and codes, regardless of whether it complied with standards at the time it was first designed. Recalculate all relevant loadbearing, design foundations and civil works to suit the building. Additionally, check the consent requirements for the Resource Management Act and make sure the building complies in the new location

During the concept design phase consider a building’s life, it may change ownership several times and be used for many different purposes. The original design dictates how easy it is to retrofit the building and how much waste is created during each renovation. Some design considerations include:

• maximise the distance between loadbearing components or design the loadbearing components to the edge of the building to allow flexibility with the internal arrangement of partitions or temporary walls
• use modular design techniques so that adding on to or altering the building is easier in future
• design for a greater load on the foundations and lower-storey supports to allow for upper storeys to be added in future
• allow good access to wall and ceiling spaces to allow for service upgrades and modifications
• allow flexibility with lighting, heating and ventilation wiring and controls for changing building uses

During the concept design phase, it is also critical to designing for deconstruction. Designing for deconstruction means considering the durability or recyclability of building components and the ability for components to be separated during deconstruction for recycling or reuse. Simple things can make a big difference to wastage in the demolition phase:

• design entrances wide enough for deconstruction machinery to reach the inner building and upper floors
• specify fixing mechanisms that can be reversed without causing damage - screws, clips, bolts and gaskets in preference to rivets, mastics, adhesives and tapes
• use components and equipment that have a long life and are easily maintained so that they can be reconditioned for reuse
• specify materials that can be easily recycled
• use reversible construction and assembly sequences

During the concept design phase identify the most effective materials to use in order to reduce waste. It is important to use a broader set of criteria when choosing materials, such as:

• recyclability - whether the product or material can be easily reprocessed back into a useful product or material
• resource efficiency - less materials have been used to produce the same product
• future salvage and reuse - whether there is a useful life for the product/material following its original use
• durability - how quickly a product or material will need to be replaced - the more durable, the less wasteful

Product suppliers can tell you this sort of information, or check the information on product labels or Environmental Product Declarations (EPDs).

Specify materials that achieve waste reduction, including:

• materials and components that are reusable or can be recycled after their useful life in the building
• materials with known recycled content - this reduces the use of raw materials and helps boost the market for recyclables
• second-hand or salvaged materials
• materials where durability is consistent with the building’s anticipated life - reducing the frequency of replacement
• materials that don’t need finishes - natural timber ceilings, bricks and tiles, pigmented concrete or plaster or colour-coated long-run roofing steel - which reduces waste associated with finishing products
• prefabricated materials supplied to the specifications of your project - no resizing on site
• materials that have recyclable, reusable or no packaging

Avoid overspecifying to reduce the amount of materials going into a building. Also let your material supplier that you are wanting to reduce construction waste. Consider whether lower standards or performance specifications may be appropriate if waste can be reduced as a result.

• prepare accurate drawings - clear, comprehensive, accurate documentation will reduce the likelihood of design variations
• provide detailed drawings and instructions to contractors to minimise mistakes, rework and temporary works
• document your design, including the location of all services, keeping records of the as-built design, and leave it with the building’s owners or occupiers. This will ensure that alterations, maintenance and deconstruction are easier and less wasteful
• provide a deconstruction plan that includes a list of building materials and components as well as their design or service life and the best options for reuse, refurbishment or recycling and instructions on how to deconstruct elements