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Our checker tool is designed to give you a general indication of how likely your property is to be under-insured, over-insured, or adequately insured. It is not intended to be advice upon which you should rely. Your email address will only be used to send your Rebuild Checker results. It will not be used for marketing purposes unless you specifically opt in above.
To obtain verified information upon which you can rely, a professional assessment should be obtained. Please see our Terms of Use for further information.
Likelihood of Being Accurately Insured
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Likelihood of Being Over Insured
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Likelihood of Being Under Insured
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A mistake that cost over £10,000
A London-based commercial landlord insured a mixed-use building using an estimated market value, assuming it would be sufficient for insurance.
The property was insured for £880,000.
When a water leak caused internal damage, a claim was made for £35,000.
What happened next
The insurer applied the Average Clause. The building was underinsured compared to its true rebuild cost (£1,300,000), so the claim was reduced proportionally.
- The insurer paid £23,700
- The landlord had to cover the remaining £11,300 themselves
Why was the figure wrong
The landlord had relied on market value not the actual rebuild cost when it came to setting his sums insured.
But:
• Market value reflects demand, location and income
• Rebuild cost reflects the actual cost to rebuild the property
The real impact
There was more than just the financial impact:
• An unexpected £11,300 cost
• Disruption to tenants and rental income
• Stress during an already difficult situation
• Loss of confidence across the rest of the portfolio
How can this happen?
The Average Clause could apply to every claim.
Which means even smaller issues can become expensive and the risk is ongoing, not one-off.
The solution
A professional rebuild cost assessment provides:
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A defensible figure for insurance
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Confidence that claims will be paid in full
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Consistency across a property portfolio
So you’re not relying on assumptions when it matters most
Rebuild cost is not market value.
Market value reflects land, location and demand. Rebuild cost is what it would cost to demolish and reconstruct the building itself. The two figures are rarely the same and confusing them is the most common cause of underinsurance in the UK.
Renovations are not reflected.
Extensions, conversions, loft rooms and specification upgrades all change the rebuild cost but they do not automatically update the sum insured on your policy. The gap grows with every change that goes unreviewed.
Index linking is not enough.
Many insurers apply index-linking at renewal to adjust for inflation. But index-linking only compounds whatever figure you started with — if that figure was wrong, the adjusted version will still be wrong. It also cannot account for physical changes to the property.
No professional assessment was ever done.
The original sum insured was often set using a purchase price, a mortgage valuation or an online calculator — none of which are designed to give a defensible rebuild figure. Without a professional review, the number has no reliable foundation.
Portfolios drift out of line quietly over time.
Most landlords do not set out to be underinsured. The problem builds gradually — and without a professional review, there is often nothing to flag it until a claim or renewal makes it impossible to ignore.
The Average Clause could affect any claim
This is the detail that catches most landlords off guard. Underinsurance does not only become a problem if you lose the entire building. The Average Clause allows insurers to reduce payouts on partial claims too — in direct proportion to the shortfall in your sum insured.
What the Average Clause means.
If your sum insured is half what it should be, your insurer can pay out only half of any valid claim — not just total loss claims, but any claim. A storm that damages a roof, a fire that destroys a floor, a flood that affects part of the building: all of these can be subject to a proportional reduction if the declared value is wrong.
A straightforward illustration:
Property insured for: £400,000 | Actual rebuild cost: £800,000
If a fire causes £20,000 of damage, the insurer applies the ratio:
£400,000 ÷ £800,000 = 50% → payout is £10,000 — you cover the other £10,000 yourself.
Reduced claim payouts
The insurer pays in proportion to the ratio of declared value to actual rebuild cost — on every claim, not just total losses.
Personal funding gaps
The shortfall between the payout and the actual repair cost falls on you — potentially at exactly the wrong moment for your cashflow.
Rental income at risk
If the property cannot be occupied during repairs, loss of rent cover may also be affected if it is linked to an inaccurate sum insured.
Insurance renewal
The point at which figures are set for another year. Wrong now means wrong for twelve months more.
Renovation or conversion
Extensions, loft conversions and specification upgrades all change the rebuild cost — often significantly. The policy needs to reflect the building as it is, not as it was.
Premium increase
A significant premium movement is sometimes a prompt from your insurer that the declared figure needs reviewing. Do not assume the figure they are using is correct.
Insurer or broker query
If your insurer or broker has raised a question about your declared value, that is a direct signal the current figure needs professional support.
The risk is highest at these moments.
Underinsurance builds gradually, but certain events make it urgent. If any of these apply to you right now, reviewing your rebuild values should be the next step — not something to carry forward to the next renewal.
We match the method to the property.
Not every property needs the same level of assessment. We triage your portfolio and recommend the right mix of desktop and site assessments, rather than applying the same approach to every building regardless of complexity.
Most properties
Desktop Assessment
Completed remotely using high-resolution imagery, mapping data, property information, assessor expertise and BCIS regional cost data. No site visit required..
✓ Standard residential properties
✓ Standard commercial buildings
✓ Blocks of flats and apartments
✓ HMOs and rental properties
✓ Mixed-use where data is clear
Complex or higher-risk properties.
SITE ASSESSMENT
A surveyor visits the property to assess directly. Provides the highest level of certainty where desktop data alone is not sufficient.
✓ Listed buildings
✓ Non-standard or unusual construction
✓ High-value or high-specification properties
✓ Significant recent alterations
✓ Where data confidence is low
If desktop is not suitable for a property in your portfolio: we will tell you before we proceed, recommend the appropriate alternative, and either refund you or make no charge. You do not need to identify the right method yourself — that is part of what we do.
Built for landlords who treat property like a serious asset.
You are likely a good fit if:
✓ You manage two or more properties and want a repeatable review process
✓ You need figures your broker, insurer or lender will take seriously
✓ You want to reduce hidden exposure without chasing technical detail yourself
✓ You are approaching renewal, refinance, acquisition or post-works review
✓ You are skeptical of calculators, guesswork and generic reviews
This is less suited to you if:
— You only want a rough estimate to see what the figure might be
— You are not yet ready to act on the result
When the rebuild figure matters, "about right" is not a professional standard.
70%
UNDERINSURED
70% of UK properties are underinsured. This can severely reduce the amount paid out following a property damage claim.
23%
OVERINSURED
23% of UK properties are overinsured. If this is you, you’re paying more than you need to for your insurance.
Underinsurance and overinsurance figures are based on RCA internal analysis of 43,000+ assessments of UK properties (2025)
What our customers say
“Following a large loss on a property where the ‘Average Clause’ was raised, I found myself arranging several reinstatement valuations. This all coincided with the enforced lockdown. Thankfully I found RebuildCostASSESSMENT.com online, who were able to assess remotely at around a third of the cost of the traditional route. The really good thing is they are no ‘one-size fits all’ portal. They’re happy to accept drawings etc by email, which leads to a satisfactory outcome all round. Great service.”
Trevor Leigh, Dennis Reed Ltd
Ready to get the right figure?
Choose the option that suits you. Both include a professionally prepared PDF report with full methodology, delivered within 3–5 working days.
Desktop Assessment
£210.00 (incl VAT)
A fast, affordable, rebuild cost assessment to helpkeep your sum insured accurate and avoid underinsurance
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Fast, efficient turnaround: Delivered quickly using trusted data, maps, and public records.
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Remote & hassle-free: No need for access arrangements or surveyor visits.
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Eco-friendly, no travel required: Reduced carbon footprint compared to on-site inspections.
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Reliable for standard properties: Suitable for most residential and commercial buildings
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Helps avoid underinsurance: Ensures your insurance sum is accurate, reducing claim risks.
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RICS-regulated & insurer-trusted: Backed by chartered surveyors, widely accepted by insurers
BEST VALUE
Desktop Assessment with
3 Full Years Protection
£298.15 (incl VAT)
3 full years of protection with our desktop assessment against rebuild cost inflation to keep your property safe
All the benefits of a desktop assessment, plus:
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✔ Total 3 years of protection: Two annual refresh calculations following your initial assessment. Rebuild costs are rising every year. Without updates, your sum insured can quickly become inaccurate. and reduces the risk of being inaccurately insured. You don't need to do anything - we handle the updates for you.
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✔ Priority handling: Jump the queue with faster turnaround for requests and updates
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✔ 20% discount on property updates: If you make any changes to your property that require an assessment prior to the annual refresh, contact us for a 20% discount on the fee.
On-Site Assessment
From £675.00 (incl VAT)
Ideal for larger, complex, Grade 2* or high-value properties where greater detail is required
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On-site inspection by a RICS regulated surveyor: A physical visit ensures every detail of your property is captured.
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Maximum detail: Ideal for listed buildings, large homes, unusual layouts, or complex construction.
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Comprehensive measurement: The property is measured on-site by one of our experience surveyors.
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Suitable for high-value properties: Provides a robust rebuild cost backed by professional expertise.
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RICS-regulated & insurer-trusted: Accepted by insurers and carried out by qualified professionals.
Frequently asked questions
Review your rebuild values before the next renewal makes the decision for you.
If you manage a growing portfolio, this is the point to replace carried-forward figures and rough assumptions with professional rebuild values you can actually use.
Get your result by email. If you need a professional next step, you can move straight to an assessment. You are not committing to anything by checking first.
HOW CAN WE HELP?
LETS HAVE A QUICK CHAT
Speak to one of our team today using our live chat feature. Click on the icon in the bottom right corner of the screen.
