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How do I calculate the rebuild cost of my home?

Do you know how much it would cost to rebuild your house? Find out how a rebuild cost calculator can help you find a great buildings insurance quote.

Do you know how much it would cost to rebuild your house? Find out how a rebuild cost calculator can help you find a great buildings insurance quote.

Written by
Anna McEntee
Insurance comparison expert
Reviewed by
Andy Webb
Insurance expert
Last Updated
26 JANUARY 2023
4 min read
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Why do I need to work out the rebuild cost for my home?

Calculating the rebuild cost of your home is an essential part of applying for buildings insurance. This is because you need enough cover to protect yourself if the worst should happen and you do need to rebuild your home. You also want to get the best value for money, with the rebuild cost of your home having a direct impact on home insurance quotes.

What happens if I under or overestimate the rebuild value of my home?

If you underestimate the rebuild cost of your home, any potential insurance payout might not be enough to complete the project. You might have to cover the shortfall out of your own pocket or, in the worst-case scenario, it could invalidate your whole policy.

If you overestimate the rebuild cost of your home, you could pay more for your monthly premiums than you need to.

How much does it cost to rebuild a house?

The rebuild cost of your home is the amount of money it would take to rebuild your home to its existing design and specifications, using modern materials and techniques. Costs that will need to be considered include:

  • Demolition
  • Debris clearing
  • Architect fees
  • Planning costs
  • Cost of labour and materials
  • Installation of plumbing, electricity, ventilation and gas
  • Built-in fittings in the kitchen and bathroom

It doesn’t cover any loose fittings in the house, such as furniture or possessions – for those, you’ll need contents insurance.

Using a home rebuild calculator can make estimating the cost of rebuilding your home easier. We wouldn’t blame you for not being an expert on the subject, so using this helpful tool can help you understand the true value and make sure you haven’t forgotten anything.

Is the rebuild cost different to the market value of my home?

Yes, the rebuild cost is normally lower than the market value of your home.

It also doesn’t include the price of the land the building sits on, or other factors that affect housing prices, like location or supply and demand.

How do I work out rebuild costs for my house?

A home rebuild cost calculator is a helpful tool you can use to calculate the cost of rebuilding your home. However, depending on the type of house you’d need to rebuild, a rebuild cost calculator may not always be the most accurate. Here are some examples of when you’d need to do some extra work:

If you recently bought your home

The rebuild cost should be included on your mortgage valuation or deeds. Otherwise, it will depend on whether you live in a standard brick house, a home constructed with non-standard materials like wood or concrete, a historic or listed building, a flat or maisonette.

If you live in a standard house made of brick or stone

You can use the house rebuild cost calculator provided by The Building Cost Information Service (BCIS) of the Royal Institution of Chartered Surveyors (RICS) to work out the cost. To use the BCIS rebuild cost calculator properly, you should work out your home’s floor area.

Alternatively, Comparethemarket can help you calculate your house rebuild cost using the BCIS rebuild cost calculator service when you compare buildings insurance.

If you live in a ‘non-standard’ home

A non-standard home is one not made of standard construction materials like brick or stone – or a historic or listed building. Homes built using non-standard materials – for example, timber or concrete – are likely to be more complicated and expensive to rebuild. If this is the case, it’s a good idea to get specialist home insurance.

If you live in a non-standard home, it’s best to get in touch with a professional surveyor. They’ll complete a detailed assessment of your house and provide a professional Rebuilding Cost Assessment. Find out more about types of home survey.

Another option is to find an insurance provider that offers ‘blanket’ coverage of a set amount (£500k, £1m or sometimes unlimited) if you’re really unsure of the rebuild cost. But it’s best to get a professional surveyor’s opinion before you go down this route.

If you live in a listed building, this could also significantly increase the cost of rebuilding your home. To find out if your home is listed and what grade it’s listed as, contact English Heritage, Historic Scotland, Cadw or the Northern Ireland Environment Agency, depending on which area of the UK you live in.

If you live in a leasehold flat

Most flats in the UK are leasehold. If yours is one of them, then it’s the responsibility of the building owner or management company to provide an accurate rebuild cost. They’ll likely pass on some of the cost to you as part of their service charge.

If you live in a freehold flat

You’ll need to calculate the rebuild cost yourself and get the professional opinion of a surveyor. In this case, simply knowing the square footage of your flat won’t predict the rebuild value as it’s likely other parts of the structure will also need to be rebuilt.

Find out more about buildings insurance for flats.

Will the rebuild cost increase if I make changes to my home?

If you decide to add an extension, conservatory or a loft conversion, the rebuild value of your home will increase. You’ll need to reassess the cost and inform your insurance provider, otherwise you may be underinsured and you’ll have to pay the difference in the event of a claim.

Read our guide to how home improvements can affect your home insurance policy.

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Frequently asked questions

What information do I need to use the rebuild cost calculator?

To use the BCIS rebuild cost calculator you need to create an account and log in. You’ll then be asked some questions about your home, including:

  • The type of property – detached, terraced or semi-detached?
  • How many floors/storeys your property has
  • Your postcode
  • The year your home was built (or best estimate)
  • The gross external floor area – called the GEFA
  • The number of bedrooms and bathrooms
  • If you have a garage (that’s not included in the GEFA) or a cellar
  • If your walls are brick or stone
  • If the roof is tile, slate, flat or thatched
  • If your home has any special architectural features

What is my home’s GEFA and how do I calculate it?

To use the rebuild cost calculator you’ll need to know your home’s gross external floor area (GEFA). To work this out, first measure the external length and width of the ground floor walls in metres or feet. Multiply these numbers to get the square footage of the ground floor area. If the upstairs level – or levels – are the same size, then you can simply multiply the square footage for the downstairs by the number of floors. If it’s different, you’ll need to calculate it separately and add the numbers together for a total rebuild figure.

Your total GEFA also includes extensions, integral garages (that you can enter through a door in the house), chimney stacks and conservatories – basically anything that’s part of the house. But you don’t need to include separate outbuildings like greenhouses, sheds, parking areas or attached garages.

What counts as a non-standard home?

A standard home is made of brick or stone with a slate or tile roof. Your home is probably classed as non-standard if it’s made from:

  • Glass
  • Plastic or fibreglass
  • Concrete, asphalt or shingle
  • Metal, including corrugated iron walls or frames
  • Wood, including timber frames
  • Wattle and daub

Your home will also be classed as non-standard if it has a thatched roof or a flat roof.

Non-standard homes are often more expensive to rebuild as the cost of materials, and labour will need to be taken into account in your buildings insurance. If you live in a non-standard property, you should hire a chartered surveyor to evaluate the rebuild cost, so you have an accurate figure.

Anna McEntee - Insurance expert

Anna’s all about delivering fantastic insurance products at a great price. Value is the most important thing for Anna, as she cuts through the jargon and finds what’s most important and worth your hard-earned money.

Learn more about Anna

Andy Webb - Insurance expert

Andy Webb is an award-winning personal finance journalist and broadcaster. Combined, his Be Clever With Your Cash blog, Andy Clever Cash YouTube channel and Cash Chats podcast have been read, watched and listened to by millions.

Learn more about Andy

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