How do I calculate the rebuild cost of my home?

Do you know how much it would cost to rebuild your house? You might be wondering why you need to know? Read on to get the lowdown…

Do you know how much it would cost to rebuild your house? You might be wondering why you need to know? Read on to get the lowdown…

Andy Webb
Insurance expert
4
minute read
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Last Updated 17 NOVEMBER 2022

Why do I need to know how much it would cost to rebuild my home?

Calculating the rebuild cost of your home is an essential part of applying for buildings insurance.

The rebuild value is the amount it would cost to rebuild your home from scratch if it was destroyed, for example, by fire, flood or a storm

It’s important to get this cost right. If you underestimate it, the insurance pay-out 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. But if you overestimate the rebuild cost, you could waste money on unnecessary insurance that you don’t need.

It’s heart-breaking to consider losing your home, but sadly it does happen. Having the right buildings insurance in place means you’ll be in the best position to pick up the pieces and start again if the worst does happen.

How much will it cost to rebuild my home?

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

It covers the cost to build your home to its existing design, using modern materials and techniques, including: 

  • demolition
  • debris clearing
  • architect fees
  • planning costs
  • labour and materials
  • installation of plumbing, electricity, ventilation and gas
  • built-in fittings in the kitchen and bathroom. 

It 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. 

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

How do I find out the rebuild cost of my home? 

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.

BCIS rebuild cost calculator

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 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 – one not made of standard construction materials like brick or stone – or a historic or listed building, it’s best to get in touch with a professional surveyor to 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 leasehold flat (most flats in the UK are leasehold) then it’s the responsibility of the building owner or management company to find out the 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.

What other factors might affect the rebuild cost of my home?

If you live in a home that’s made from non-standard materials– for example, timber or concrete – then it’s likely to be more complicated and expensive to rebuild.

And if your house has distinctive features, such as a thatched roof, or was built by a well-known architect, it’s very likely to cost more to rebuild. If this is the case, it’s a good idea to get specialist home insurance

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.

What happens 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.

Frequently asked questions

What information do I need to use the rebuild 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 happens if I underestimate or overestimate the rebuild cost of my home?

If you underestimate the rebuild cost and your home is later destroyed, your insurance provider may not cover the full cost of the repair. That means you’d have to pay the remainder of the bill yourself.

Conversely, if you over-insure your home, you’ll be paying a higher premium and wasting money, so it’s definitely worth having an accurate figure to take to your insurance provider.

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 estimate.

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