If you're having any major building work done on your house, such as loft conversion or extension, you will need to let your house insurance provider know. Structural changes bring increased risks, with builders coming into and out of your home, building materials on site, and potentially parts of the property exposed to the elements. Your home insurance is also likely to go up if the work increases the cost of rebuilding your home. If you don’t tell your insurer your home is undergoing renovation, you may find that your policy is invalid in the event of a claim.