When a home is sold in the UK, Private Residence Relief means no Capital Gains Tax is due if the owner has one home, has lived in it as their main home throughout, has not let part of it out or used part exclusively for business, the grounds are under 5,000 square metres and it was not bought just to make a gain; where tax is due, GOV.UK says the costs of improvement works such as an extension can be deducted from the gain.

The starting point: Private Residence Relief

Capital Gains Tax applies to the gain made when property is sold. GOV.UK sets out when a home sale is free of it. No Capital Gains Tax is payable if all of the following apply: the owner has one home and has lived in it as their main home for all the time they have owned it; they have not let part of it out (a lodger does not count); they have not used a part of it exclusively for business purposes; the grounds, including all buildings, are less than 5,000 square metres (just over an acre) in total; and they did not buy it just to make a gain. If all of these apply, the relief is automatic and there is no tax to pay.

When a conservatory can complicate the position

A conservatory can matter to the conditions in two ways. If it is used as an office, GOV.UK says a room used as a temporary or occasional office does not count as exclusive business use. A part of the home used exclusively for business is one of the listed conditions. Second, letting part of the property out is another. GOV.UK says that if any of the conditions do not apply, there may be some tax to pay, and points to its guidance on eligibility. The guide to using a conservatory as a home office covers the practical side of the space.

Working out the gain

Where tax may be due, the gain is usually the difference between what was paid for the home and what it was sold for. GOV.UK says market value is used instead in certain cases, including where the property was a gift, was sold for less than it was worth to help the buyer, was inherited and the Inheritance Tax value is not known, or was owned before April 1982. These points are set out in the GOV.UK guide for a home sale.

Deducting the cost of a conservatory

GOV.UK states that the costs of buying, selling or improving a property can be deducted from the gain. Those costs include estate agents’ and solicitors’ fees, and the costs of improvement works, for example for an extension. Normal maintenance costs such as decorating do not count. A conservatory is an extension of the home, so the cost of building it is the kind of improvement expense that the guidance describes, whereas repainting the frames or replacing worn seals is maintenance. GOV.UK also says some costs cannot be deducted, such as interest on a loan to buy the property, and advises contacting HMRC where it is unclear whether a cost can be deducted.

Reporting and paying

If Capital Gains Tax is payable, GOV.UK says it must be reported and paid on most sales of UK property within 60 days. The tax-free allowance for individuals, which GOV.UK gives as £3,000 (£1,500 for trusts) when checked on 25 September 2026, is a separate figure that can be set against gains; allowances are set for each tax year, so the current figure should be checked at the time of sale. VAT on the works is covered in the guide to VAT on conservatories, and buyers’ checks on a home with a conservatory are covered in the guide to buying a house with a conservatory.

FAQs

Do I pay Capital Gains Tax on my home if I added a conservatory?

Not if Private Residence Relief applies in full, which GOV.UK says is automatic when all its conditions are met. A conservatory does not by itself remove the relief.

Can I deduct the cost of building a conservatory from my gain?

GOV.UK says the costs of improvement works, for example for an extension, can be deducted from the gain, while normal maintenance costs do not count.

Does a home office in a conservatory affect the relief?

GOV.UK says a room used as a temporary or occasional office does not count as exclusive business use, but exclusive business use of part of a home is one of the conditions to check.

The bottom line

Selling a home with a conservatory is usually free of Capital Gains Tax under Private Residence Relief. Where tax is due, GOV.UK says the cost of improvement works such as an extension can be deducted from the gain, and any Capital Gains Tax on most UK property sales must be reported and paid within 60 days. This is general information, not tax advice; HMRC or a qualified tax adviser should confirm the position for a specific sale.

Sources

This guide draws on the following primary sources, current as of 25 September 2026:

• GOV.UK, “Tax when you sell your home: Private Residence Relief”
• GOV.UK, “Tax when you sell your home: Work out your gain”
• GOV.UK, “Capital Gains Tax: what you pay it on, rates and allowances”

Related guides

Compare Conservatories is an independent guide. We may earn a fee from some links; this never affects what we write. This article is general information, not legal or planning advice on any specific property — always confirm requirements directly with your local planning authority.