Calculating the rebuild cost of your home

How to work out the rebuild cost of your home

Written by Sarah Tooze

Reviewed by Saarrah Mussa

5 min read

Updated: 25 Feb 2025

In this guide / article

Your home’s rebuild cost – sometimes referred to as ‘buildings sum insured’ – is different to its market value. Here’s why it’s important to get the right figure for your home insurance quote

Key takeaways

Rebuild cost is the sum insured amount to rebuild your house from scratch if it is destroyed
You need an accurate rebuild cost to get the right amount of home insurance cover
Underestimating your rebuild cost could lead to a shortfall if you need to make a claim in the future

What is the rebuild cost of my house?

The rebuild cost of your house is the amount it would cost in labour and materials to reconstruct it from the ground up if it was completely destroyed beyond repair. This could be the result of a fire, flood or storm, or subsidence, for example.

Factors used to calculate your home’s rebuild cost

Property type: Whether it's a multi-story house, a bungalow, or a flat
Property style: Is your house detached, semi-detached or terraced?
Property size: The number of rooms (such as bedrooms and bathrooms) and floors (including cellars, lofts, and garages) you have, plus the external floor area
Property age: If the building is listed or is older than average then this could increase the rebuild cost
Cost of labour: The cost of labour changes over time and some homes may require the work of a specialist
Cost of materials: If your house is not made from brick, then it might require non-standard materials which can drive up the rebuild value
Planning costs: You may need the services of an architect to plan your rebuild, and large or complex homes may have more expensive planning costs
Debris clearing: The cost of clearing debris, as well as the cost of demolishing the old property, if a rebuild requires starting from scratch

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

Yes. The market value relates to how much someone might pay to buy your property. This takes into account the value of the land itself and other lifestyle factors, like proximity to schools or transport links. So it’s likely to be higher than the rebuild cost.

In a few cases, where houses are made out of non-standard building materials, the market value could be lower than the rebuild value – but this is very rare. In these circumstances you should insure against the higher rebuild cost rather than the lower market value.

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

You need an estimated rebuild figure for rebuilding your home so that you know how much buildings insurance to take out. Insurance providers will use the rebuild value to determine your premium, and what payout you would receive if you made a claim.

If you have a mortgage, your provider may also insist you have buildings insurance in place as a condition of the loan.

How do I calculate the rebuild cost?

Use the Building Cost Information Service (BCIS) rebuild cost calculator
Hire a surveyor from the insurance industry to carry out an assessment
Use the figure on your mortgage valuation if you’ve recently bought your home

Using the BCIS rebuild cost calculator

Information you’ll need - the home’s external floor area for both upstairs and downstairs, what type of property you have, what style it is (detached, semi-detached, or terraced), the number of storeys, and the number of bedrooms.

Is the BCIS rebuild cost calculator free? - yes, it’s free to use the BCIS rebuild cost calculator but you need to register, and you can only use the calculator four times in any 12-month period.

Property types the BCIS rebuild cost calculator covers - general brick houses and flats. It does not cover listed buildings, houses built before 1720, unusual designs or timber construction (such as log cabins or timber framed and clad houses). However, if your house is timber framed and clad in brick then the BCIS says its reasonable to use the calculator based on a brick house.

Using a surveyor

When to use a surveyor - if you have a non-standard construction and you want to be accurate, a professional will be able to calculate the rebuild cost.

How to find a surveyor - you can search for someone on the Royal Institution of Chartered Surveyors (RICS) website.

Cost of a surveyor - an RICS Home Survey varies from a few hundred pounds for a basic survey to more than £1,000 for bespoke services.

Did you know...

The price of rebuilding costs, such as the price of raw materials and labour costs, rose by 21% in the two years to January 2024 and was up 2.6% in January 2025 compared to the previous year, according to The House Rebuilding Cost Index (HRCI).

How do I work out the area of my house in square metres?

Measure the length and width of the ground floor walls and multiply the two figures together. If the upstairs is identical to the downstairs, simply double the ground floor area. If it isn’t, check your property’s deeds or an estate agent’s floor plan, if available.

Don’t forget to include any additional square meterage such as converted loft space.

What factors might affect the rebuild cost of my house?

Non-standard materials:

If your home is made of non-standard materials such as thatch or even timber and concrete, it could be more expensive to rebuild than a typical bricks and mortar home. This is because the material costs more or it might require a specialist builder who charges a premium.

The type of property:

If you live in a block of flats, the rebuild may affect the entire building rather than just your home, making it more difficult to estimate how much cover is required. Living in a listed building also affects the rebuild cost.

How do I know if my home is listed?

To find out if your home is listed, check:

English Heritage (England)
Historic Scotland (Scotland)
Cadw (Wales)
The Northern Ireland Environment Agency (Northern Ireland)

What happens if I underestimate the rebuild value of my house?

If you underestimate the true cost of rebuilding your home and then need to make a rebuild claim you could find yourself with a shortfall when the pay-out doesn’t match the cost, meaning even more unexpected expenses.

What happens if I overestimate the rebuild value of my house?

If you overvalue the rebuild amount, you’ll be over-insured and pay too much in premiums.

What if I live in a flat or maisonette?

Given flats and maisonettes are constructed differently to houses, a surveyor may be required for an accurate valuation.

If you live in a leasehold property, first check that the freeholder (building owner) has buildings insurance in place. Many flats and apartments in the UK are leasehold properties, with the cost of the insurance often passed on to the leaseholder through a service charge.

If you rent your home then your landlord is responsible for buildings insurance.

Will my rebuild cost change if I renovate my house?

Yes, if you add an extension, conservatory or loft conversion to your home, the rebuild cost is likely to increase as the house is bigger.

If this is the case, recalculate your rebuild cost and tell your insurance provider so they can update your premium. If you don't inform your insurance provider you may be left uninsured for any renovations you've made to your home and will have to cover the difference in the event of a claim.

If you aren’t changing the fundamental structure of your home it’s unlikely the rebuild cost will change.