Housing Price Growth and the Construction-Cost Channel

Standard commentary treats inflation as a single trend that is either easing or accelerating. The record of Inflation (21220) shows two more specific structures. The first is a gap between housing cost growth and general price growth that opens and closes in distinct episodes rather than persisting. The second is a construction-cost channel that led housing costs in the 2021–22 episode but not in the episode now under way.

Where the composite reading comes from

The certified composite for the June quarter 2026 is +2.1049σ, ranked 100.0 against 22 quarters. Because the five inputs carry equal weight, each contributes one fifth of its own Z-score.

Finding one: the housing gap runs in episodes

Measured as annual growth, housing costs and general prices have diverged in three distinct phases since 2021.

December quarter 2021 to June quarter 2024: housing costs rose faster than headline CPI in every quarter. The gap peaked at 3.28 percentage points in the September quarter 2022, when housing costs rose 10.53 per cent against 7.25 per cent for headline CPI.

September quarter 2024 to June quarter 2025: the gap reversed. Housing costs rose more slowly than headline CPI for four consecutive quarters, with the widest shortfall of 1.38 percentage points in the December quarter 2024 (1.03 per cent against 2.41 per cent).

September quarter 2025 to the present: the gap reopened, reaching 3.05 percentage points in the March quarter 2026 and 2.86 points in the June quarter 2026 (6.80 per cent against 3.94 per cent).

The practical consequence is that the housing gap is a condition to be dated and monitored, not a structural constant to be assumed. A model that permanently loads a housing premium onto headline inflation would have overstated housing cost growth through 2024 and early 2025.

Finding two: the construction-cost channel changed its timing

PPI House Construction measures the cost of building before it reaches the consumer-facing housing group. In the 2021–22 episode it moved first: construction producer prices were rising 8.85 per cent a year in the September quarter 2021, while housing costs were rising 1.53 per cent. Housing cost growth followed, reaching 10.61 per cent by the December quarter 2022.

The current episode ran the other way. Housing cost growth re-accelerated to 4.77 per cent in the September quarter 2025, while construction producer prices were rising only 0.52 per cent. Construction cost growth followed a quarter later: 2.31 per cent in the December quarter 2025, 4.13 per cent in the March quarter 2026 and 5.92 per cent in the June quarter 2026. In the March quarter 2026 the construction index moved above +2σ for the first time in the record.

The renewed rise in housing costs therefore did not begin in construction input costs. The housing group covers rents, utilities and other housing charges as well as the prices owner-occupiers pay for new dwellings, and the timing shows the 2025 acceleration was under way before builders’ input costs began to rise. Construction costs are now adding to the pressure rather than having started it.

Advanced practitioner implications

Credit analysis: serviceability and cost models anchored to headline CPI currently understate housing cost growth by about 2.9 percentage points a year. The same models would have overstated it through 2024 and early 2025. Use the dated housing growth rate, not a standing adjustment.

Portfolio strategy: construction producer prices accelerated in each of the last three quarters. With the channel now active behind the housing group rather than ahead of it, cost pressure on new supply is building while the consumer-facing gap is already wide.

Valuation: replacement-cost and insured-value assumptions should be re-based on construction and housing price growth specifically. House construction producer prices have risen 47.0 per cent since the December quarter 2020, against 25.7 per cent for headline CPI.