A 0.1% construction cost rise is hiding diesel up 76% since February

Construction costs barely moved in October. Average trade rates across Auckland, Wellington, Christchurch, Dunedin, Hamilton and Palmerston North rose just 0.1 percent last month, according to QV CostBuilder. In the same month diesel rose 19 percent and now sits 76 percent above February levels.

Both numbers are true. Only one of them should be in your tender spreadsheet. Builders have been given a pause in the averages, not a discount on the inputs, and treating stability as a trend is how fixed-price contracts turn into losses.

Rises are cancelling out falls

The October breakdown shows why the average flatters. Excavation rose 3.9 percent, piling and demolition 0.6 percent. Processed timber products jumped 6.2 percent, MDF 2.8 percent, reinforcing 2.7 percent, roofing and cladding 1.6 percent and insulation 1.1 percent. Offsetting that, adhesives and sealants fell 4.2 percent, kitchen-related costs 1.2 percent and structural timber 0.2 percent. QV CostBuilder quantity surveyor Martin Bisset put it plainly: the overall picture is steady, “but that doesn’t mean every part of a build is standing still. Where your costs will move most depends heavily on what you’re building, what materials you need, and how exposed the job is to fuel” (RNZ).

Translation for anyone running a civil, earthworks or foundation-heavy job: the 0.1 percent belongs to someone else. A bathroom renovation and a subdivision with heavy cut-and-fill are living in different cost environments.

Diesel has whipsawed all year

This is not a one-month blip. In April 2026 Bisset said fuel had become “the dominant cost driver in recent months”, with excavation up 7.9 percent that month, and warned pressure was building before it showed up in headline figures.

Then it reversed. In July diesel fell 20.7 percent month-on-month, dragging excavation down 4.5 percent. Even then Bisset described the mood as “cautious optimism rather than confidence in a lasting trend”, pointing to Middle East volatility.

He was right to hedge. MBIE fuel monitoring showed diesel climbing from around 243 cents a litre to almost 272 cents in a matter of weeks. Excavation rose 4.3 percent and demolition 3.7 percent, pushing annual residential build cost growth to 3.3 percent. By late August, Bisset was already repeating the line that “the headline result is very stable, but that doesn’t mean nothing is moving”.

That is a single input moving by double digits in both directions within one calendar year, driven by oil markets New Zealand has no control over. It is the definition of a risk you price for, not one you assume away.

A recovering sector with less room to absorb shocks

The wider backdrop is genuinely better, which is precisely why the margin risk matters. Treasury’s latest Fortnightly Economic Update reports construction sentiment rebounding on higher orders and output, with new dwelling consents up 5.6 percent in August and 21.1 percent year-on-year. Consents for the year to June topped 40,581, the first time above 40,000 since 2023.

But Treasury also notes margins are being squeezed by increased competition, and that the net share of firms raising prices fell from 41 percent to 26 percent in the September quarter. It calls the fuel-driven cost pressure transitory, “though they could prove sticky.”

Put those together. More work is coming, rivals are bidding harder for it, and the ability to pass on cost increases is shrinking. A contractor who wins a tender on razor-thin pricing in October, then eats a 20-cent diesel jump in December, has bought revenue at a loss.

Price the fuel, not the average

The practical response is not complicated. Strip fuel-intensive line items out of general contingency and price them separately. Excavation, demolition, piling, cartage and anything with heavy machine hours should carry a specific fuel allowance or, where clients will wear it, a fuel-indexed escalation clause. Timber and reinforcing deserve the same scrutiny given October’s moves.

Clients should expect it too. A developer insisting on fixed prices for earthworks-heavy jobs in this environment is either paying a hidden premium or setting up a dispute later.

The recovery in consents is real and worth celebrating. But the cost index will keep printing calm numbers right up until the components stop cancelling each other out. With diesel 76 percent above February and the Middle East no calmer, the builders who come out of this cycle in profit will be the ones who priced the volatility rather than the average.

Sources

• RNZ: Construction costs hold steady despite hefty diesel price increases (2026-10-29)
• QV: Fuel pressure building as construction costs hold steady (2026-04-28)
• QV: Diesel drop keeps construction costs stable… for now (2026-08-03)
• MPAmag: Diesel price fall gives builders brief reprieve on costs (2026-08-03)
• MPAmag: Diesel price swing pushes building costs back up (2026-09-01)
• QV: Diesel rebound drives construction costs upward (2026-09-01)
• Loan Market: Construction costs hold steady despite movement beneath the surface (2026-08-24)
• Treasury: Fortnightly Economic Update – 15 October 2026 (2026-10-15)