Abnormal as % of Build represents the percentage of non-standard, unexpected, or one-off construction costs compared to the total project build cost. These abnormal costs can arise from unforeseen site conditions, design changes, delays, or regulatory requirements and are distinct from standard construction budgets. For UK property developers, understanding this metric is crucial for accurate financial forecasting, risk management, and capital allocation within property development finance structures. Calculated as (Abnormal Costs ÷ Total Build Cost) × 100, it provides a clear indicator of budget deviations and informs lenders and investors about potential project cost exposure.
Abnormal as % of Build sits beneath Hard Costs, measuring abnormal costs as a proportion of the core build budget so that site-specific burdens can be tested separately from ordinary construction expenditure. It is commonly considered alongside Hard Cost to Soft Cost Ratio, as both help developers and lenders understand whether the cost structure is balanced, distorted, or carrying unusual pressure. In practice, abnormal costs may be shaped by legal, planning, or site constraints, including matters documented through Planning Obligation requirements. Within the capital stack, higher abnormal cost exposure can affect lender appetite, equity requirements, contingency allowances, and overall project viability.
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