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28 Mar 2019
Adam Bate

How to calculate the rebuild cost of your home


Money and a house

From using a rebuild cost calculator, to working out the square metres of your property, here's what you need to know about calculating your rebuild costs.


You’ll need to know the rebuild cost of your home when you come to buy buildings insurance.

Having an accurate figure can help prevent you from over or under-insuring your house.

This is important because, in the unfortunate event that your home requires a complete rebuild, you could be left to cover any difference in price.

What is the rebuild cost of my house?

As the term suggests, the rebuild cost is the amount of money you’d need to rebuild your home from scratch.

Rebuilding takes into consideration the price of labour and materials that would be involved in building a house identical to yours on the land you own.

The final sum is usually less than the market value of your home, i.e. the amount you’d expect to get if you were selling it.

This is because factors such as the land, location, school catchment area, and supply and demand are taken into account.


How to calculate the rebuild cost

If you own a standard, brick-built home there are two ways to calculate the rebuild cost of your home.

The first is to use the Building Cost Information Service’s (BCIS) house rebuilding cost calculator.

And the second is to hire a chartered surveyor who will carry out a professional assessment. 

READ MORE: How to calculate the value of your home contents


How to use a rebuild cost calculator

You can access the BCIS rebuild cost calculator via this website

Before you use the building cost calculator, you’ll need to know your home’s external floor area for both upstairs and downstairs.


How to work out square metres

To work out the floor area of your home, go outside and measure the length and width of the ground floor walls, then multiply these two figures together.

If the upstairs is identical to the downstairs, simply double the ground floor area.

If it’s different, calculate the upstairs area separately and add it to the downstairs result. 

Once you've done this calculation, you'll be ready to use the calculator, which will give you the rebuilding cost per square metre, and the total for your property.


Hire a surveyor

There are a number of restrictions to the BCIS calculator. For example, historic or listed buildings aren’t covered and neither are houses that aren't built of brick.

Therefore, often the best way to get an accurate rebuild cost of your home is to get a surveyor round.

They’ll carry out detailed measurements of your house and then prepare a professional Rebuilding Cost Assessment.

This should set you back around £250 for a basic survey, and you can find a local surveyor through RICS (an independent professional body).

Find out more about listed building insurance

What about flats and maisonettes?

Construction methods are different for flats so, if you own a flat or maisonette, it’s best to let the surveyor do the work instead of using a calculator.

It’s worth noting that, as most flats are leasehold, a management company or building owner will probably already have buildings insurance in place, which will typically be paid for via service charges.

Find out more about flat insurance

Updating your home’s rebuild cost

If you make any structural changes to your house, such as a new extension or a loft conversion, these are likely to affect the rebuild cost.

If the rebuild cost increases without your buildings insurance increasing to match, you could end up underinsured and left to cover the difference if anything was to happen.

Therefore it’s important to check that your buildings insurance covers anything that adds extra value to the rebuild cost of your home.

So before you start work on your next big project, it’s worth chatting to your insurer first about home insurance options to suit your needs.


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