Increased Council tax banding 40 years later

[Hectorsmother]

Posting on here for traffic.

We bought a house in October 2025 that had had an extension done in the 1980s.

For 40 years the house has been on band X, and we have continued to pay the same band for nearly 6 months. Council have written to say they have re-evaluated the property's value in 1994 and deemed it was worth more than they thought and therefore because of the sale we are now being moved up a higher tax band.

This feels utterly farcical and money grabbing from the council.

It is mindboggling that the people whose chosen to build the extension and the enjoyed it for FORTY Years didn't have to pay this higher council, but the people that bought it completely ignorantly and weren't even born at the time of the extension now are slapped with this extra bill.
And apparently that is the way of the world.

Council tax is based on the idea that people with bigger / more expensive housing should pay more. Just like income tax. If your house is extended it is bigger (and presumably more expensive) than a neighbour with no extension. It doesn’t seem unreasonable to be in a higher band. Seems odd that the review is at point of sale, but I’d bet that the government don’t want to discourage people from improving their own homes for quality of life (rather than resale value) reasons.

This just happened to us and we were equally shocked. We bought our house 15 months ago and the extension was completed over 20 years ago. The registered owner change at Land Registry seems to have been the prompt.

You get advised when you do an extension that the council tax band may be re-evaluated/increase at the point of sale. I thought this was pretty well known but obviously not! That's one of the reasons that people extend rather than moving.

I do think that your conveyancer should have picked it up as I assume you got the signed off documents from building control

We have paid more than our neighbours in similar-sized houses for decades. If we ask to be reassessed, the risk is they are moved to our band and we stay the same. We haven’t done it but it does annoy me that they pay less.

It is government legislation and must be adhered to by the Council. They don't make the rules.

Unfair definitely but I guess many taxes aren't exactly fair.

It is common practice to reband after a sale, but given that the extension was already there when the property was originally valued from what you're saying, I would imagine you would have reasonable ground to challenge it. Is the banding out of step with other equivalent properties locally?

Money Saving Expert has good information on challenging banding more generally which would be a good place to start.

I understood that when you buy a property, they can shift it up one band, if changes have been made by the vendors since they bought it. It happened when I bought our house. You can challenge it if you feel you have a strong case, but if the previous owners have improved or extended their house while living there, the council tax wouldn’t have changed until the house was sold, no matter how long ago it was done.

We extended our house and knew it would be re banded when we sold. When we did sell, I informed viewers that it was likely to go up.

The house we bought had had a small extension. A few months after we moved in, a representative from the council called round to assess the property. Fortunately the extension didn't increase the square footage of the house by enough to affect the band.

The Council does not band houses - the Valuation Office Agency does. The Council then has to bill based on what’s in the valuation list.
The VOA can revalue when a property changes hands.
You can make an appeal to have your banding reduced but this can take ages and be aware that they can decide to increase the band further as part of the appeal.

OP you can appeal the rebanding.

In my circumstances I purchased a house at band F, did my research and after much persistence it was rebanded as an E.

Don’t sit back and be passive about this. I had to fight the valuation office but with a surveyor I instructed the VO eventually backed down!

Could you put in a challenge based on neighbouring properties of similar size being the original band? Assuming they are. Use Martin Lewis guide, it’s brilliant.

I’d be annoyed at my conveyancer/myself for not doing the due diligence.

It has just taken me ninety seconds to see which houses on my street have an improvement marker.

At some point they’ll have to change the council tax system anyway because it isn’t an equitable system and most of us don’t pay enough, considering huge swathes of the population have chosen to make the council responsible for their care needs later in life.

The timelines on this don't make sense. If the extension was done 40 years ago in 1986, then it would have been assessed at 1991 for council tax including the extension. So it shouldn't have needed to be reassessed.

I moved into a new house and now pay band D. My best friends house is bigger than mine but because it hasn’t been rebanded it’s a band A.
I think there needs to be a national shake up rather than just pockets like you’re experiencing. It’s not fair on those paying correctly by modern standards.

I’ve just checked our house. https://www.gov.uk/council-tax-bands

We bought it as a 2 bed and have extended to a 3 bed - council website states Improvement Marker = Yes

Because you are now being charged the correct band. You were previously paying less than others who have the same type of house and now you are paying the same as other people who have the same type of house. That's perfectly normal and fair. I can't see a single wrong with this.

Thank you for this genuinely valuable response.

So to continue with this analogy - let's say you had a job and you get a promotion with increased pay but do not pay any tax on the increase for 40 years. You then retire but don't tell your new hire about the promotion and 6 months in the newbie has to pay increased tax and all of this according to most people is fair, ethical and above board.

This is exactly what you are saying.

Yeah and the extension work with associate paperwork was all already completed before this date of 1991 (sorry I'd be previously posting 1994).

There has to be a statue of limitations. I mean there are time limits for varying crimes and infringements but council tax is forever!

We had the same 2 years ago

What was the time difference between the extension work and the change of banding out of curiosity?

Thank you for this. Thank you for picking up on the details. THIS is why I am so flabbergasted and I cannot believe some of the ham fisted responses on here going "more big more tax"

Thank you.

Same happened to us

Of course it isn’t the same. You benefit by owning the improved asset, which will make you more money when you sell than it would have without the improvements. The original owners have had to invest the cost of the improvements in the house, so that was their ‘loss’ in the circumstances - and it will have been more costly than the differential between the two council tax bands for the period in which they weren’t paying it. You keep talking about a ‘statue of limitations’ (if you’re going to appeal please note it’s STATUTE, not a sculpture) but your liability only goes back to your purchase, a mere six months, so the difference between what you have paid in those months and what you now owe in back payment for the adjustment up one and can’t be as enormous as you make out. And anyone buying a house should be budgeting for fluctuations in mortgage rates, insurance rates, council tax, energy price rises etc etc when deciding how much they can afford to spend!