The phrase selling part of your house can mean several different things in practice. It might refer to selling off part of the garden or land, selling a physical part of the building such as an annex or a flat, or selling a beneficial share of the ownership interest in the property. Each of these is a different type of transaction with different legal, tax, and practical implications.

This guide covers the most common scenarios in which someone might want to sell part of their home and what each involves.

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Selling Part of the Garden or Land

Selling off part of a garden or plot is probably the most common type of partial property sale and is a relatively straightforward legal process. If you have a large garden and want to sell a portion of it as a separate plot, typically for someone to build a new home on, the process involves splitting the title of the land at HM Land Registry and selling the separated parcel to the buyer.

Planning permission

Selling land for development without planning permission is possible, but the land is worth considerably less than land with planning permission already granted. Most buyers for residential plots will want confirmation that a new dwelling can be built before purchasing, whether through an existing consent or subject to planning as a condition of the sale. The seller can apply for planning permission before selling, or sell subject to planning permission being granted.

Tax implications

Selling part of your garden may trigger capital gains tax if the area sold exceeds the permitted garden or grounds that qualify for principal private residence relief. PRR relief covers the dwelling and its garden or grounds up to half a hectare, or larger where the property genuinely requires more extensive grounds. For most residential properties, selling part of a garden is within the relief and no CGT is due. For large plots, CGT may apply on the portion sold. A solicitor and accountant should be consulted before proceeding.

Mortgage lender consent

If your home has a mortgage, the lender has a charge over the entire property. Selling part of the land reduces the security available to the lender, and their consent is required before any part of the title can be separated and sold. Most lenders will consent provided the security remaining after the sale adequately covers the outstanding mortgage, and the proceeds of the land sale are often required to be applied in partial reduction of the mortgage.

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Selling a Physical Part of the Building

If your home includes a self-contained annex, a flat above a garage, or another physically separate unit, it may be possible to sell that unit as a separate property. This requires the unit to be capable of being separately titled, which typically means it needs its own separate access, its own services connections or at least the ability to be independently serviced, and sufficient independent use to justify a separate title.

Converting part of a house into a separate flat and selling it involves obtaining planning permission for the change of use, Building Regulations approval for the conversion works, and a new leasehold or freehold title for the unit being sold. The legal and planning complexity is significant, and the costs of conversion and compliance can be substantial.

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Selling a Share of the Ownership

Selling a share of the legal ownership means adding another person to the title of the property as a co-owner, who pays for their share. This is different from selling the physical property or land: the property remains intact but is now owned jointly.

This type of arrangement is occasionally used within families, for example to allow a parent to transfer an interest in the property to a child while remaining in the home. It has significant implications for CGT, inheritance tax, and the lender's position if there is a mortgage. All parties who own a share of the property are jointly liable for any mortgage, and the consent of existing mortgage lenders is needed before a co-owner can be added.

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Summary

Selling part of your home is possible but the approach and implications depend on what exactly you are selling. Selling garden land is the most common and straightforward option, typically involving title splitting and potentially planning permission. Selling a separate physical unit such as a flat or annex requires planning permission, Building Regulations compliance, and new title creation. Selling a share of the ownership is a legal transaction that affects all owners' tax positions and requires mortgage lender consent. All three routes require professional legal advice before proceeding.