Glossary

Material increase

A building improvement (extension, loft conversion) that can trigger a re-band when the property is sold.

A material increase is any improvement that adds value — extensions, loft conversions, garage conversions. The band doesn't change while you own the home; it's only reassessed at the next sale. This is why some homes appear underbanded despite obvious extensions — the improvement hasn't triggered a review yet.

Related terms

Material reduction
A change that reduces a home's value — demolition, subsidence — and can lower the band immediately.
Valuation Office Agency (VOA)
The government agency that sets and reviews council tax bands for every home in England and Wales.

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