Two situations trip people up: buying a new build, and extending an existing home. Both are banded on a rule that surprises everyone — the 1991 value, not today's price — and extending doesn't do what most people fear. Here's how each one actually works.
When a new home is finished, the VOA still has to place it in a band based on what it would have been worth on 1 April 1991 (2003 in Wales) — decades before it was built. That's an estimate, and estimates go wrong. It's why a brand-new house can sit a band above older, similar homes nearby that were valued directly in 1991.
Worth checking: if your new build is banded higher than established homes of similar size and type on the same development or street, that gap is exactly the kind of evidence a challenge is built on.
The big fear — "if I extend, my council tax goes up" — is mostly wrong. Improving or extending your home does not change your band while you own it. Instead:
If you're buying: a home with an improvement indicator may be re-banded after your purchase. It's worth knowing before you commit — and worth checking whether the current band is right in the first place.
Challenge Your Band reads the official VOA data for your street — including whether a property carries an improvement indicator — and compares your home to like-for-like neighbours, so you can see whether a new build or post-extension band is actually fair.