Service Description: Council Tax banding lists, and banding appeals
Answer: That will depend on the valuation officer who will need to determine whether or not the extension has increased the market value of your home significantly enough to increase the banding. This will normally only occur when the property is sold. When a property is improved, legislation prevents the VOA from increasing the existing band until there is a relevant transaction which means that the property has been sold as a freehold, or a lease for a period of 7 years or more has been granted. - Related Link