Fitouts account for 32 percent of a commercial office building’s lifecycle emissions, and the average commercial fitout generates 368.6 tonnes of waste, according to the New Zealand Green Building Council. Those two figures reframe how the industry should think about interiors.

The conversation about construction carbon has focused almost entirely on base build: structural steel, concrete, facades, operational energy. Meanwhile the interior gets ripped out and replaced every five to ten years, over and over, across a building life of sixty years or more. The base build is built once. The fitout is built six or seven times.

The churn problem

A commercial office fitout in New Zealand typically has a life of five to ten years, driven by lease cycles rather than by the physical condition of the materials. A lease expires, a tenant leaves, a make good clause requires reinstatement, the space is stripped back, and a new tenant builds a new fitout in the same space.

At that point almost everything goes to landfill. Partitions that were structurally sound. Ceiling tiles with decades of life left. Joinery that was made to last. Carpet that is worn but not failed. Light fittings that work.

Multiply that by the number of tenancies in a building and the number of lease cycles in a building’s life, and the interior becomes the largest repeating carbon and waste event in the asset’s existence. The NZGBC figure of 32 percent of lifecycle emissions is the consequence.

Where the carbon actually sits in a fitout

Embodied carbon in fitout is concentrated in a relatively small number of elements:

Metals. Aluminium framing in glazed partition systems, steel studs, ceiling grid. Aluminium in particular is carbon intensive to produce.

Plasterboard. High volume, and historically almost entirely landfilled at end of life.

Floor coverings. Carpet tile and vinyl are petrochemical products with meaningful embodied carbon and short replacement cycles.

Joinery substrates. Board products, adhesives and finishes.

Services. Mechanical, electrical and fire modifications, which are frequently replaced wholesale even where the existing installation is serviceable.

Furniture. Often excluded from fitout carbon assessments entirely, despite being a substantial component and having an even shorter replacement cycle than the fitout itself.

What actually reduces it

The interventions that work, roughly in order of impact:

Keep the fitout

The lowest carbon fitout is the one you do not build. Where a landlord accepts an incoming tenant taking over a good quality existing fitout, the entire carbon and waste event is avoided. This is a commercial negotiation as much as a design decision, and it is easier in a market with elevated vacancy where landlords are motivated to reduce re letting cost and downtime.

Retaining and adapting rather than stripping and rebuilding should be the default question at the start of every project, not an afterthought.

Design for disassembly

Where new work is required, design it so it can come apart. Mechanical fixings rather than adhesives. Standard modular dimensions rather than bespoke cut to fit. Demountable partition systems rather than stud and plasterboard built in place. Accessible services rather than buried ones.

This has a direct commercial benefit as well as an environmental one. A fitout designed for disassembly is cheaper and faster to strip out at lease end, which reduces the make good cost the tenant carries in year six or ten.

Specify for lower embodied carbon

Material selection is where design decisions translate into carbon outcomes. FSC certified timber over higher carbon alternatives. Recycled content in metals and boards. Low VOC finishes for indoor air quality alongside the carbon question. Products with published Environmental Product Declarations so the carbon claim is verifiable rather than asserted.

Steel and concrete together make up more than half of New Zealand construction’s carbon footprint, and an NZGBC commissioned report identified potential to decarbonise around 40 percent of the embodied carbon footprint. In fitout specifically, the equivalent leverage sits in aluminium, plasterboard and floor coverings.

Manufacture offsite

Offsite manufacturing reduces waste in a way that on site construction cannot match. In a factory, material yield is optimised by software, offcuts are captured and sorted at source rather than mixed in a site skip, and production runs are batched to minimise waste in the first place.

New Zealand research has found that offsite modular systems reduce embodied carbon compared with traditional on site methods, and identifies prefabrication and waste reduction as among the larger carbon savings opportunities available to the sector.

Complete Construction’s robotic batch one facility in Auckland operates on this principle. Advanced CNC and robotic systems maximise material yield, and the waste that is generated is separated at source and diverted through established streams: timber to biofuel, gypsum to fertiliser, metals to recycling.

Divert what you do remove

Even a well designed project generates waste at strip out. The question is where it goes. Separated at source and directed to established streams, most of it has somewhere to go other than landfill. Mixed in a single skip, none of it does.

What this means commercially

The environmental argument for reducing fitout churn happens to align with the commercial one, which is not always true in sustainability.

Tenants increasingly require sustainability credentials. Corporate and government occupiers apply minimum standards, and JLL research in New Zealand found Green Star certified offices command sales premiums from 3.7 percent for a 4 star rating to 7.5 percent for 6 star, and rental premiums from 1.5 to 2.25 percent across the same range. Buildings holding both Green Star and NABERSNZ ratings showed the highest occupancy and lowest vacancy.

Investors are asking. Around 22 percent of investors now assess circularity according to the Green Building Council of Australia, and that proportion is rising rather than falling.

And a fitout designed for adaptation and disassembly costs less to change and less to remove. The make good bill at lease end is smaller. The next tenant is more likely to keep it rather than strip it.

Frequently asked questions

How much of a building’s carbon comes from fitout? The New Zealand Green Building Council states that 32 percent of a commercial office building’s lifecycle emissions come from fitouts. This reflects the fact that interiors are replaced every five to ten years across a building life measured in decades, so the fitout carbon event repeats many times over.

How much waste does a commercial fitout generate? The NZGBC puts the average commercial fitout at 368.6 tonnes of waste. Most of this is generated at strip out, when materials that remain serviceable are removed to make way for a new tenant’s fitout.

What is design for disassembly? Designing a fitout so its components can be separated and reused at end of life. In practice this means mechanical fixings rather than adhesives, standard modular dimensions rather than bespoke cut to fit, demountable partition systems, and accessible rather than buried services. It reduces both embodied carbon and the cost of make good at lease end.

Does offsite manufacturing reduce waste and carbon? Yes. Factory production optimises material yield through software driven cutting, captures and sorts offcuts at source rather than mixing them in a site skip, and batches production runs to minimise waste. New Zealand research has found offsite modular systems reduce embodied carbon relative to traditional on site methods.

Is there a commercial return on a lower carbon fitout? JLL research in New Zealand found Green Star certified offices command sales premiums of 3.7 to 7.5 percent and rental premiums of 1.5 to 2.25 percent depending on rating level, with the highest occupancy and lowest vacancy in buildings holding both Green Star and NABERSNZ ratings. Separately, a fitout designed for disassembly reduces the tenant’s make good cost at lease end.

Sources

  • New Zealand Green Building Council, Green Star Fitouts, lifecycle emissions and fitout waste data
  • Green Building Council of Australia, investor circularity assessment data
  • New Zealand Green Building Council, embodied carbon methodology and commissioned decarbonisation research
  • JLL, Turning green to gold, New Zealand green building value research
  • New Zealand academic research on offsite modular construction and embodied carbon, Energies, 2024
  • Complete Construction environmental statement

This article is general information. Carbon and waste figures are drawn from published industry research and vary by project.