Your building needs to be insured for its total rebuild cost – how much it would cost to rebuild your home if it was totally destroyed.
It’s important you don’t overpay on your insurance by insuring for the rebuild cost rather than the market value of your property. The rebuild cost is usually lower as the market value as this will account for the local area as well as the property itself, such as proximity to public transport and schools, and the crime rate in the area.
If you have recently bought your home the rebuild cost will be on your mortgage valuation or survey. Alternatively, you can use the Building Cost Information Service rebuilding cost calculator, which you will also find on MoneySuperMarket.