PROPTECH-X : New Home Build Costs Increasing by 21.8%, Compared with Average Sales Value Growth of 13.1%

Key Takeaways

• Build costs rose 21.8% vs 13.1% sales value growth
• Viability assessments rely on BCIS data in 95% of cases
• Standard developer margin: 20% market, 6% affordable
• Building Safety Levy adds $37‑$50 per sqm starting Oct 2026
• Section 106 funded 45% of affordable homes in 2023/24

Pulse Analysis

The latest Fine Margins report underscores a widening cost‑value gap that could reshape England’s housing pipeline. While construction expenses have surged nearly 22% over the past four years, buyer‑paid prices have lagged at just over 13%, squeezing profit buffers. Developers now face tighter breakeven points, especially on sites with limited economies of scale, prompting a reassessment of project scopes and financing structures. This divergence also raises questions about the sustainability of the 1.5 million‑home target set by the government, as each new build must now clear a higher cost hurdle before delivering acceptable returns.

Policy layers are compounding the financial strain. Recent mandates—Biodiversity Net Gain, nutrient neutrality, stricter sustainability standards, and updated Building Regulations—add direct and indirect costs to every scheme. The forthcoming Building Safety Levy, slated for October 2026, will levy $37‑$50 per square metre on most new residential projects, though exemptions exist for affordable and small‑scale developments. Such levies, combined with existing Section 106 contributions that funded 45% of affordable units in 2023/24, erode margins and force developers to seek higher gross development values or innovative cost‑saving measures. The cumulative effect is a more cautious market, where only projects with robust, data‑driven viability models can proceed confidently.

In response, the industry is moving toward standardized viability assessments. The study notes that 95% of appraisals use BCIS cost data and that a 20% margin for market housing and 6% for affordable housing have become de‑facto benchmarks. This consistency aids planners and local authorities in evaluating proposals against clear, comparable criteria, reducing uncertainty while preserving flexibility for site‑specific challenges. As cost pressures intensify, rigorous, transparent viability testing will be essential to align policy goals with commercial realities, ensuring that new homes can be delivered without compromising financial sustainability.