Nearly a third of UK homeowners have never reviewed their buildings insurance cover, according to recent research, which means millions of people could be paying for the wrong level of protection or, worse, discovering gaps only after damage has occurred. That figure matters because the moment you exchange contracts on a house, you become legally responsible for the structure — and if a storm tears through the roof the night before completion, you are the one footing the bill. Over the years covering the UK property market, I have seen this exact scenario catch buyers off guard more often than you would expect. The problem is not that buildings insurance is hard to find; it is that most people do not realise how much hinges on getting the timing and the sum insured exactly right.
Here is what you actually need to know. Buildings insurance covers the cost of repairing or rebuilding your property if it is damaged by something like a fire, flood, or storm. It is not a legal requirement in the UK, but nearly every mortgage lender will insist you have it in place before they release the funds. If you are buying with cash, you can technically skip it — but that would mean covering the full rebuild cost out of your own pocket if the worst happens. I have written before about the hidden costs of homeownership, and uninsured structural damage is one of the biggest. A smart leak detector like the X-Sense Wi-Fi Water Leak Detector can catch small problems before they become expensive claims, but the real protection starts with the policy itself.
What buildings insurance actually covers — and what it does not
The most important thing to understand is that buildings insurance is not the same as contents insurance, and the two are often sold separately. Buildings insurance covers the structure itself: walls, roof, floors, permanent fixtures like fitted kitchens and bathrooms, and sometimes outbuildings like garages and sheds. Contents insurance covers your belongings — furniture, electronics, clothes, and so on. If you are buying a house, your lender will only care about the buildings cover, but you will want both once you move in.
Getting the rebuild cost right is where most people slip up. You can use online calculators to estimate it, or you can pay a surveyor for a more precise figure. I would always recommend the surveyor route if the property is unusual — a period home, a listed building, or something with non-standard construction materials. A standard new-build estate is usually straightforward enough for a calculator. The key is to check that the sum insured is enough to cover a full rebuild, not just the mortgage amount. If you underinsure, the insurer can reduce your payout proportionally, which is a nasty surprise at claim time. For more on the full financial picture of buying, have a look at the true cost of UK home ownership.
Why the timing of your insurance matters more than you think
Exchange of contracts is the moment the property becomes your legal responsibility. If the house burns down between exchange and completion, you are the one who has to sort it out — the seller is no longer liable. That is why you must have buildings insurance in place from the exchange date, not from completion day. I have seen buyers delay arranging cover because they thought they did not need it until they got the keys, and that gap can be financially devastating.
Consider this scenario: you exchange contracts on a Friday, with completion scheduled for the following Wednesday. Over the weekend, a burst pipe floods the ground floor. Without buildings insurance in place, you are looking at thousands of pounds in repairs before you even own the property. With a policy active from exchange, you make a claim and the work gets done. The difference is night and day. The research from Uswitch shows that a significant portion of homeowners only think about insurance after a problem occurs, but by then it is too late.
What I tend to notice is that first-time buyers are the most vulnerable here. They are so focused on the mortgage offer, the survey, and the moving logistics that insurance gets pushed to the bottom of the list. My advice is to sort the buildings insurance quote before you even set an exchange date. That way, when your solicitor confirms the exchange is happening, you can activate the policy immediately. A monitored alarm system like the Yale Smart Home Alarm can also help reduce your premium by making the property more secure, which is worth asking your insurer about.
Where people go wrong with buildings insurance claims
Even with a policy in place, mistakes during the claims process can cost you. The most common errors fall into a few clear patterns, and knowing them in advance can save you time, money, and frustration.
Underestimating the rebuild cost
This is the single biggest mistake I see. People insure their house for the purchase price or the mortgage amount, neither of which reflects the actual cost to rebuild. If your rebuild cost is £300,000 but you only insured for £200,000, the insurer may apply what is called average — meaning they only pay out two-thirds of any claim. A £60,000 repair bill would then net you just £40,000. The fix is straightforward: use a rebuild cost calculator or get a surveyor’s assessment before you buy the policy. Do not guess.
Not understanding what is excluded
Standard buildings insurance covers fire, flood, storm, subsidence, and escape of water, but exclusions vary widely between policies. Some policies exclude damage from frozen pipes unless you have maintained adequate heating. Others cap subsidence claims at a lower limit. The guide on building insurance when buying a house makes clear that you need to read the policy wording, not just the summary. If you are unsure about a specific exclusion, ask the insurer directly before you buy. A carbon monoxide alarm like the FireAngel Carbon Monoxide Alarm is a simple way to reduce one common risk, but it will not help if your policy excludes certain types of damage entirely.
Failing to update cover after renovations
If you add an extension, convert a loft, or install a new kitchen, the rebuild cost of your property goes up. Many homeowners forget to tell their insurer, which means they are underinsured from the moment the work finishes. The same applies if you add security features like a smart lock — your premium might go down, but only if you report the change. I always set a calendar reminder for the anniversary of my policy to review the sum insured and any changes to the property.
Waiting too long to report a claim
Most policies require you to notify the insurer of damage within a reasonable timeframe — often 30 days for storm damage, but sometimes less for escape of water. Delaying can give the insurer grounds to reduce or deny the claim. If you discover damage, take photos, make temporary repairs to prevent further harm, and contact your insurer the same day. Keep receipts for any emergency work, as these are usually recoverable under the policy.
→ Scroll right to see all columns
| Mistake | Consequence | How to avoid it |
|---|---|---|
| Insuring for market value instead of rebuild cost | Payout reduced proportionally (average clause applied) | Use a rebuild cost calculator or hire a surveyor |
| Not reading policy exclusions | Claim denied for a risk you assumed was covered | Read the full policy wording before buying |
| Failing to update cover after renovations | Underinsured from the moment work finishes | Notify insurer of any structural changes immediately |
| Delaying notification of damage | Claim reduced or denied for late reporting | Report damage within 24 hours; take photos and keep receipts |
How to get the right buildings insurance for your new home
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Getting the right policy is not complicated, but it does require a few deliberate steps. Here is the process I recommend to anyone buying a house.
Calculate the rebuild cost first
Before you even look at quotes, you need a reliable rebuild cost figure. The Building Cost Information Service (BCIS) offers an online calculator that most insurers accept. Alternatively, your mortgage valuation report sometimes includes a rebuild estimate, though it is not always accurate for older properties. If the house has unusual features — thatched roof, timber frame, stone walls — pay for a surveyor. It costs a few hundred pounds but can save you thousands if you ever need to claim. Once you have the figure, add a buffer of at least 10% to account for inflation and unforeseen costs.
Compare policies on coverage, not just price
Price comparison sites are useful, but they only show you what is cheapest, not what is best. When comparing, look at the level of cover for subsidence (some policies cap it at £50,000), the excess amounts, and whether accidental damage is included or optional. Also check the policy’s definition of storm damage — some insurers require wind speeds above a certain threshold, which can leave you unprotected in a typical UK storm. I always recommend getting at least three quotes from different providers and reading the policy documents side by side. If you need legal advice on a disputed claim, a property lawyer can help you understand your rights.
Arrange cover before exchange day
Once you have chosen a policy, you can usually set the start date to coincide with exchange. Most insurers allow you to take out the policy in advance and specify a future start date. Tell your solicitor the policy is in place so they can confirm it to the lender. If you are buying with a mortgage, the lender will want to see proof of insurance before they release the funds. Keep the policy document and the insurer’s contact details handy — you may need them at short notice.
Review your cover annually and after any changes
Buildings insurance is not a set-and-forget product. Rebuild costs rise with construction inflation, which has been running well above general inflation in recent years. If you add an extension, convert a loft, or even install solar panels, the rebuild cost changes. Set a reminder to review your policy every year on the renewal date. If you have made improvements that increase security — like fitting a Nuki Smart Lock Pro — tell your insurer; you may qualify for a discount. If you have not made any changes, you can still shop around for a better price, but make sure the new policy matches or exceeds the old one in coverage.
Frequently asked questions about buildings insurance when buying a house
Can I buy buildings insurance before I have exchanged contracts? ▾
What happens if the seller’s insurance is still active after exchange? ▾
Do I need buildings insurance if I am buying a flat? ▾
Can my mortgage lender force me to use their insurance? ▾
What is the difference between rebuild cost and market value? ▾
Does buildings insurance cover subsidence? ▾
Getting buildings insurance right when you buy a house is one of those tasks that feels like a box-ticking exercise until something goes wrong. The key is to treat it as a core part of the buying process, not an afterthought. Calculate the rebuild cost accurately, arrange cover before exchange, and review the policy annually. If this was useful, you might also want to read the ultimate UK home buying checklist.
Sources and Further Reading
Common UK home buying mistakes to avoid — Real examples of what can go wrong during the purchase process and how to sidestep them.
Understanding home price index trends before buying — How market trends affect your purchase timing and insurance costs.
Building Insurance When Buying A House: What You Need To Know In June 2026. UK Care Guide, 2026.
UK Insurance Horizon Scanner 2026. Hogan Lovells, 2026.
50+ home insurance statistics 2026. Uswitch, 2026.
