Class T Council Tax Exemption: Unoccupied Annexes With Planning Restrictions

What Class T Does

Class T gives a 100% council tax exemption to an unoccupied annexe in England that cannot be let separately from the main dwelling because of a planning restriction. When it applies, the bill on the annexe is zero.

It sits in the Council Tax (Exempt Dwellings) Order 1992 alongside the better-known Class W exemption for dependent relatives. While Class W covers occupied annexes, Class T covers the empty ones — provided there is a legal reason the space cannot be used as an independent rental.

The Three Legal Requirements

To qualify for Class T, the annexe must satisfy all three conditions:

1. Unoccupied. Nobody lives in the annexe. It does not matter whether the space contains furniture — Class T applies regardless of furnishing status. The test is simply whether anyone resides there.

2. Part of a single property. The annexe must form part of a single property that includes another dwelling. The statutory test does not set a separate same-title or physical-curtilage requirement; a detached annexe can qualify if it forms part of the same property.

3. Cannot be let separately without breaching planning controls. This is the critical condition. The planning permission, or a Section 106 planning obligation, must prevent the annexe from being let separately from the main dwelling without breaching planning control.

A typical planning condition reads: "The accommodation hereby permitted shall not be occupied at any time other than for purposes ancillary to the residential use of the dwelling known as [Main House], and shall not be let, sold, or occupied as a separate unit of accommodation."

What Does Not Count as a Planning Restriction

Your own preference not to let the annexe does not qualify. Neither does difficulty finding a tenant, a personal decision to keep the space for family use, or the practical inconvenience of shared utility meters.

The restriction must come from planning control, such as a planning condition or a Section 106 planning obligation. If you are unsure whether your annexe has one, check the planning decision notice issued when the annexe was built or converted. Most local planning authority websites publish these on their planning register, searchable by address.

How Class T Interacts With Empty Home Premiums

Since April 2024, councils can apply a 100% empty home premium on properties that have been unoccupied and substantially unfurnished for more than one year. Since April 2025, they can also apply a 100% second home premium on furnished properties that are nobody's sole or main residence.

An annexe with a Class T exemption is protected from both premiums. The exemption status takes priority — while Class T is active, no premium applies. This matters particularly for families who have an annexe that sits empty between relatives or after a bereavement.

When Class T Ends and What Replaces It

Class T continues for as long as the three conditions hold. If someone moves into the annexe, it stops being unoccupied and Class T ends — but if the new occupant is a dependent relative, Class W may then apply.

If the planning restriction is removed or varied (for example, following a successful application to discharge the ancillary-use condition), Class T falls away. The annexe becomes a standard chargeable dwelling, though the 50% family annexe reduction may still apply if a relative moves in.

How to Claim

Submit a claim to your local billing authority with a copy of the planning decision notice showing the ancillary-use restriction. Some councils also accept a Section 106 agreement or a copy of the condition extracted from the local planning register.

The council may conduct a physical inspection to verify the annexe is unoccupied. Processing typically takes 21 to 28 working days.

Our Annexe Discounts and Exemptions Guide includes a checklist for gathering the right planning evidence and a step-by-step walkthrough of the claim process, including what to do if the council refuses your application.

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