Having some building work done? Inform your home insurance provider

May 7, 2025

It’s vital that you inform your home insurance provider before any building work commences and that you update the buildings sum insured once the job is complete. Here’s why …

What is the ‘sum insured’ and why does it matter?

Probably the most important feature of your home insurance is the total ‘sum insured’. That is the maximum amount your insurer is obliged to pay in case of a successful claim for loss or damage.

Typically, the total sum insured envisages a worst-case scenario in which your home is totally destroyed – following a catastrophic fire or flood, for example. In that case, the site would need to be cleared, and your home completely rebuilt. This amount needs to cover all these costs of reinstatement – from clearing the site, engaging the relevant professionals (such as architects, engineers, and lawyers), and rebuilding your home.

It is important to remember that the total sum insured reflects the current estimated reinstatement costs – and not, for example, what you paid for your home or its current market value.

How extensions and renovations affect your insurance

If you have had any kind of building work on your home – whether that is an extension to the kitchen, a loft conversion, or the addition of a garden room – the overall cost of rebuilding your home is naturally going to increase.

If those estimated rebuilding and reinstatement costs go up, it follows that you also may need to increase the total sum insured under your home’s building insurance. Failure to do so could leave you with inadequate funds to rebuild the refurbished and extended home if the worst happens.

Once any renovation or extension is complete, of course, you are likely to install new furniture, appliances, or in-home technology. Those additions also need to be reflected in a potentially updated and increased total sum insured under your home’s contents insurance.

Why you must inform your insurer

If you plan to call in the builders, let your insurers know beforehand. They will want to reassess the insured risks of your home – and may also want to adjust the premiums accordingly. A failure to inform your insurer of any renovations or extensions could invalidate a claim you subsequently make.

It will be prudent, therefore, to keep your insurers fully in the picture during the building works and, of course, upon completion so you can update and increase the total sum insured of your home insurance policy.

Empty property undergoing renovation

In some cases, you may be vacating your property while it undergoes renovation. In this case, you will need specialist unoccupied property insurance for properties undergoing works, so discuss this with your insurance provider.

What homeowners often overlook

Even though you’ve taken on board the importance of updating the total sum insured following building works, there are some pitfalls commonly encountered by some homeowners.

Remember that even non-structural changes to your home can significantly affect the risks of fire or flooding. Don’t overlook changes such as a new bathroom, the installation of solar panels, or an open-plan reconfiguration of your home.

How to stay protected

It makes sense to regularly review your home insurance policy – especially if renovation work or an extension is planned.

To accurately assess the likely increase in value of your home – and, therefore, the revised total sum insured – you might want to consult a professional surveyor or valuer.

In any event, receipts and other documents relating to the work done may prove helpful in re-evaluating your home.

Further reading

For wider reading on the implications of renovation work or an extension for your home insurance you might want to refer to:

• the Association of British Insurers (ABI) in conjunction with the Royal Institution of Chartered Surveyors (RICS) offers a Building Cost Information Service which you may use to calculate the up to date reinstatement cost of your home;

• RICS also publishes more detailed information about residential valuations;

• the Handbook of the Financial Conduct Authority (FCA) contains useful advice for all insurance policyholders; and

• reports by the Financial Ombudsman Service regularly spotlight problems encountered by policyholders who are underinsured (where the total sum insured fails to cover the amount claimed).

Before the builders turn up

Remember to contact your insurer or insurance broker before making any changes – renovations, extensions, or non-structural alterations – to your home. Not only will this help you to update and increase the total sum insured following those changes but might also avoid any costly surprises if a future insurance claim is subsequently rejected.

As an aside, things like adding a lick of paint or simply “sprucing up” your home typically do not require you to advise your home insurance provider.

Further reading: The importance of reviewing home buildings insurance