The £76,000 viability gap: why rising regulation and construction costs are stalling UK housing delivery

A £76,000 headwind for every new home

UK housebuilding has a cost problem that goes well beyond headline inflation. According to the Home Builders Federation's Viability Crunch report, the cumulative cost of building a typical new home has risen by around £76,000 since 2020 — equivalent to more than 20% of the average new home value of £365,000 as of June 2025. For apartments in high-rise buildings, the uplift is sharper still: an estimated £98,000 per home, driven by additional Building Safety Regulator processes and fire safety compliance that simply don't apply to low-rise houses.

This is not a story about one tax, one regulation, or one supply shock. It's the compounding effect of a decade's worth of policy change — Building Safety Levy, Future Homes Standard, Biodiversity Net Gain, nutrient neutrality — landing on top of genuine construction cost inflation, at a moment when housebuilders have the least capacity to absorb it. For developers, lenders, and investors underwriting UK residential schemes, understanding where this £76,000 actually comes from — and which schemes are most exposed — is now central to viability testing.

Unpacking the cost stack

The HBF's breakdown is instructive because it separates genuine inflation from policy-driven cost growth, and the split is roughly even:

• Materials and labour inflation: around £37,000 per home. Material costs are estimated to have risen more than 40% since 2020 (roughly £28,500 per home), with labour costs up 23% (around £8,500 per home) — a legacy of pandemic-era supply chain disruption and a persistent construction skills shortage that continues to constrain build-out rates.

• Regulatory costs: over £23,000 per home. This includes roughly £7,770 tied to building regulations changes, £5,700 for Biodiversity Net Gain, and around £10,200 linked to the Future Homes Standard, which from 2027 will require heat pumps and solar PV coverage across a large share of new-build roof space.

• Taxes and levies: over £7,000 per home. Landfill Tax, the forthcoming Building Safety Levy (due October 2026 and expected to raise £3.4bn), and inflationary increases to existing Section 106 obligations all sit in this bucket.

• Site-specific costs: around £7,000 per home. Nutrient mitigation and other local requirements, which vary significantly by site and local authority.

For apartment schemes, Building Regulation changes and Building Safety Regulator gateway processes add a further £22,000 on top of the baseline figure, pushing the per-home uplift to roughly £98,000. That's a meaningful difference in viability arithmetic for any scheme assessed on a per-unit basis, and it helps explain why high-rise, higher-density schemes — precisely the product type most needed in supply-constrained urban markets — are proving hardest to get past appraisal stage.

Crucially, the assumption that land values can simply absorb these increases is reaching its limit. Landowners still need sufficient incentive to sell, which means developers are increasingly having to renegotiate Affordable Housing and Section 106 contributions just to keep marginal sites moving — a dynamic that shows up directly in planning pipeline data.

The pipeline is already responding

The viability pressure isn't theoretical — it's visible in the planning numbers. REalyse planning data shows approved residential units across England and Wales falling from over 344,000 in 2023 to approximately 203,000 in 2025, with planning approval rates that had held broadly steady around 71% through 2023–2025 beginning to slip in early 2026 as local authority planning capacity comes under strain.

That contraction is consistent with wider industry data: new housing starts fell around 28% in 2024/25, and completions in England dropped 12.6% in the first half of 2025 versus the same period a year earlier — a decline of roughly 16% from the 2020 peak, with just 208,000 new homes completed in 2024/25. Housing remains the weakest construction subsector by activity, lagging commercial and infrastructure work, which tend to carry fewer of the residential-specific regulatory costs outlined above.

The pain is not evenly distributed. The top 10 housebuilders have managed modest completions growth (+2.8% to mid-2025), largely because scale allows cost absorption across a larger land bank and multiple regions. SME developers — who historically delivered around a third of UK new homes — saw completions fall 7.2% over the same period. CG Fry & Son's recently reported 18% profit decline, attributed directly to regulation costs and a flat market, is a useful single-company illustration of a sector-wide squeeze: smaller balance sheets have far less room to carry delayed conditions, unexpected mitigation requirements, or a weak sales period.

Off-plan sales — which historically let developers pay down development finance before completion — have fallen to a 12-year low of around 33% in 2025, down from 49% in 2016, adding further financing cost pressure precisely when build costs are also rising. For lenders assessing development finance applications, this combination of slower sales, thinner margins, and rising input costs warrants closer scrutiny of scheme-level cash flow assumptions, not just headline GDV.

What this means for viability testing and site selection

For institutional investors, developers and lenders, the practical implication is that generic appraisal assumptions are increasingly unsafe. A £76,000-£98,000 swing per unit is large enough to move a scheme from viable to unviable on its own, independent of movements in sales values or interest rates. REalyse-style comparables and planning data can help stress-test these assumptions at a granular level — benchmarking achieved £/sqft values and days-to-sell against the actual cost stack a scheme is likely to face, factoring in build typology (low-rise versus high-rise), local Section 106/CIL obligations, and site-specific constraints such as flood risk or nutrient neutrality zones that add to the £7,000 site-specific cost line.

For lenders and credit teams, the regional concentration of this pressure matters too. Schemes in markets where house price growth has been constrained — London and the South East notably, where Savills estimates construction cost inflation has run roughly 80% ahead of house price growth since 2020 — are more exposed to the viability gap than schemes in markets with stronger price momentum to offset rising build costs. Comparable evidence at a local authority or postcode district level, rather than national averages, is the more reliable basis for underwriting.

Outlook: a delivery problem as much as a policy problem

The Office for Budget Responsibility's November 2025 outlook projects housing delivery will only exceed 300,000 dwellings in a single year (2030/31) across the forecast period, implying the gap between ambition and output persists for some time yet. The Building Safety Levy's October 2026 introduction, alongside scheduled annual increases to Landfill Tax through to 2030, suggests the cost stack is more likely to grow than shrink in the near term, even as industry bodies lobby for a moratorium on new policy costs.

For the market, this points toward continued consolidation — larger housebuilders with balance sheet depth absorbing share from SME developers who increasingly can't carry marginal sites through to completion — and a widening gap between planning consent and construction start. For professionals navigating this environment, the opportunity lies in sharper, more localised viability analysis: identifying where demand and achievable values genuinely support the current cost base, rather than relying on national housing targets to signal where delivery will actually happen.