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How home improvements affect your Council Tax band

Posted by: , Posted on: - Categories: Council Tax

[English] - [Cymraeg]

Many homes in England and Wales are renovated and extended. In this blog, we explain what happens to your Council Tax band when you make changes to your home. We also explain what an improvement indicator means and what you need to consider when purchasing a new home.

The VOA follows strict laws around valuation. This means, legally, we cannot change the Council Tax band of a property that has been improved until it is sold, or there is a general revaluation of all domestic properties. This helps to make sure homeowners are not penalised for improving or maintaining their home.

Instead, we give the property an improvement indicator.

Improvement indicators show that major structural changes have been made to a property. This includes things like adding an extension or carrying out large-scale renovation work. We don’t consider redecorating to be a major change.

If we’ve added an improvement indicator to your home, it will be shown on the property information for your address when you search your postcode online.

Improvement indicators prompt a review of the Council Tax band once a property is sold.

The process

Improvement indicators are added to properties when we receive information. For example, your council will let us know when you have built an extension. Or we may become aware of property changes during the course of our work.

We follow a three-step process:

  1. We hold the details of any major changes made to a property on a digital system, and add an improvement indicator to the Council Tax band
  2. Once the property has been sold, the system prompts us to review its Council Tax band. This will only happen if an improvement indicator is in place
  3. When we review the property’s Council Tax band, we look at the changes that have been made

Council Tax bands cover a range of values, and often changes do not increase the value of a home enough to move it into a higher band.

In most cases, we only review the Council Tax band after a sale, so any changes to the band will only affect the property’s new owners. But there are some circumstances when we’ll review a property’s Council Tax band without a sale, such as when an annexe is created.

If you’ve purchased a property with an improvement indicator

If you’ve purchased an improved property and we increase its Council Tax band after a review, the new band will apply from the date we notify your local council. This is usually a few days after we complete our review.

We welcome your comments about this blog below but cannot discuss individual cases. Please do not share any personal information. We will not be able to publish any comments that include personal details.

Please direct all queries about individual cases to our contact form.

[English] - [Cymraeg]

Sut mae gwelliannau i’r cartref yn effeithio ar eich band Treth Gyngor

Mae adnewyddu ac ymestyn yn rhywbeth cyffredin sy'n digwydd i lawer o gartrefi yng Nghymru a Lloegr. Yn y blog hwn, rydym yn esbonio beth sy’n digwydd i’ch band Treth Gyngor pan wnewch newidiadau i’ch cartref. Rydym hefyd yn egluro beth mae dangosydd gwelliannau yn ei olygu a beth sydd angen i chi ei ystyried wrth brynu cartref newydd.

Mae’r VOA yn dilyn cyfreithiau llym ynghylch prisio. Mae hyn yn golygu bod y gyfraith yn ein rhwystro rhag newid band Treth y Cyngor eiddo sydd wedi’i wella hyd nes iddo gael ei werthu, neu hyd nes bod yr holl eiddo domestig yn cael eu hailbrisio’n gyffredinol. Mae hyn yn helpu i sicrhau nad yw perchnogion tai yn cael eu cosbi am wella neu am gynnal a chadw eu cartref.

Yn hytrach, rydym yn rhoi dangosydd gwelliannau i’r eiddo.
Mae dangosyddion gwelliannau’n dangos bod newidiadau strwythurol mawr wedi’u gwneud i eiddo. Mae hyn yn cynnwys pethau fel ychwanegu estyniad neu wneud gwaith adnewyddu ar raddfa fawr. Nid ydym yn ystyried ail-addurno i fod yn newid mawr.

Os ydym wedi ychwanegu dangosydd gwelliannau i’ch cartref, bydd yn cael ei ddangos ar yr wybodaeth am eiddo ar gyfer eich cyfeiriad pan fyddwch yn chwilio am eich cod post ar-lein.

Mae dangosyddion gwelliannau’n ysgogi adolygiad o’r band Treth Gyngor unwaith y bydd eiddo’n cael ei werthu.

Y broses

Rydym yn ychwanegu dangosyddion gwelliannau pan mae gwybodaeth yn dod i law. Er enghraifft, bydd eich cyngor yn rhoi gwybod i ni pan fyddwch wedi adeiladu estyniad. Neu efallai y byddwn yn dod yn ymwybodol o newidiadau i eiddo yn ystod ein gwaith.

Rydym yn dilyn proses tri cham:

  1.  Rydym yn cadw manylion unrhyw newidiadau mawr a wneir i eiddo ar system ddigidol, ac yn ychwanegu dangosydd gwelliannau at y band Treth Gyngor.
  2. Unwaith y bydd yr eiddo wedi’i werthu, mae’r system yn ein hysgogi i adolygu ei fand Treth Gyngor. Bydd hyn ond yn digwydd os bydd dangosydd gwelliannau ar waith.
  3. Pan fyddwn yn adolygu band Treth Gyngor yr eiddo, rydym yn edrych ar y newidiadau a wnaed.

Mae bandiau Treth Gyngor yn cwmpasu ystod o werthoedd, ac yn aml nid yw newidiadau yn cynyddu gwerth cartref digon i’w symud i fand uwch.

Yn y rhan fwyaf o achosion, dim ond ar ôl gwerthu eiddo y byddwn yn adolygu band Treth Gyngor, felly bydd unrhyw newidiadau i’r band yn effeithio ar berchnogion newydd yr eiddo yn unig. Ond mae rhai amgylchiadau pan fyddwn yn adolygu band Treth Gyngor eiddo heb werthiant, megis pan fydd rhandy’n cael ei greu.

Os ydych wedi prynu eiddo gyda dangosydd gwelliannau

Os ydych chi wedi prynu eiddo sydd wedi’i wella a’n bod ni’n cynyddu ei fand Treth Gyngor ar ôl adolygiad, bydd y band newydd yn berthnasol o’r dyddiad y byddwn ni’n rhoi gwybod i’ch cyngor lleol. Mae hyn fel arfer ychydig ddyddiau ar ôl i ni gwblhau ein hadolygiad.

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  1. Comment by L Chantler posted on

    Please can I request the following information.

    1. How do you value new properties built post 2008

    2. How can you challenge when there are no similar properties in a 2 miles radius.


    • Replies to L Chantler>

      Comment by Valuation Office Agency posted on

      Good afternoon, all properties are banded according to our estimate of the value it would have achieved if it had existed and been sold on 1 April 1991 (in England) or 1 April 2003 (in Wales). We compare new-build property with similar property that sold at those dates, and with nearby property that is already banded.

      You need to provide evidence to support your reasons for wanting to challenge the band, even if a comparable property is more than 2 miles away. You need to tell us what makes you think the band is wrong – you can do so by visiting

  2. Comment by Kevin White posted on

    Many home improvements which used to require planning permission now do not, meaning that those ‘improvements’ which had previously been reported to the VOA by local authorities now go undeclared and, therefore, unreported. Does this mean that domestic houses recently ‘improved’ within current planning laws go undetected?

  3. Comment by Chris posted on

    It seems highly unfair to penalise the person buying the house when the previous owner has profited from the improvements. Is there a requirement for the purchaser to be informed of the flag at the time of the purchase?

  4. Comment by Michael Chamberlain posted on

    VOA are informed by building control so if it was a legal extension under permitted development VOA should have been informed and an improvement indicator would show on the tax banding.