Sometimes we use slightly perplexing words in the property world, so if you're not sure what they mean, check out our jargon-buster.
Occurring when the value of a property falls below the outstanding mortgage.
NHBC Certificate (National House Building Council Certificate)
This is a type of building guarantee available on some newly built properties designed to cover defects within a specified time after the building is completed. Typically this can be for 10 years.