Insurance renewal season is fast approaching and for many property owners, this means one crucial question: does your current sum insured still reflect today’s rebuild cost? According to research by RebuildCostASSESSMENT.com, the short answer in 2026, is NO.
With rebuild costs still rising and insurers tightening their focus on valuation accuracy, renewal reviews are now essential for avoiding both underinsurance and unnecessary premium spending. Research by the company demonstrates the extent of the problem, with a staggering 93% of UK properties being insured for the wrong amount.*
“Renewals shouldn’t be a box-ticking exercise,” says Sharon Masters AIIRSM MARLA, Technical Lead and Surveyor at RebuildCostASSESSMENT.com. “They’re a financial checkpoint and an opportunity to make sure cover genuinely matches the cost of reinstating your property.”
According to RebuildCostASSESSMENT.com’s latest construction cost update,** average rebuild costs remain around 3–5% higher, year on year, with significant regional and building-type variations. Yet many policies remain indexed by far smaller percentages, leaving owners exposed to significant shortfalls in the event of a major loss.
Risks are not limited to underinsurance
However, risks are not limited to underinsurance. Some properties, particularly those with extensive refurbishments or where market valuations were previously used as a proxy for rebuild cost, are drifting into overinsurance territory. With the FCA’s Consumer Duty now requiring fair-value outcomes, insurers and brokers are under pressure to demonstrate that customers are paying for accurate cover.
To make sure they are properly protected, property owners should review sums insured annually, especially ahead of renewal, commission professional Rebuild Cost Assessments (RCAs) every three years or after major alterations and share up-to-date valuation data with brokers early, providing ample time for the reviewing of terms and accurate pricing.
Property portfolio owners can further streamline this process by maintaining a central rebuild cost register, ensuring visibility across multiple sites and renewal cycles. This saves time and strengthens insurer relationships by displaying proactive risk management.
“Accurate valuations are the foundation of fair insurance,” Sharon Masters adds. “When clients get this right, pricing, terms, and peace of mind just follow naturally. As renewal discussions begin for 2026, one rule for property owners stands out: review before you renew. It’s the simplest, most effective way to prevent financial surprises and guarantee that property insurance remains fit for purpose.”
Sources:
* www.rebuildcostassessment.com/post/2025-property-insurance-infographic
** www.rebuildcostassessment.com/post/uk-construction-costs-winter-2026-update