Class 3 Annexe Exception Council Tax Wales: When an Annexe Avoids the Premium

An annexe banded separately for council tax can attract a second-home or empty-home premium in Wales — even when it sits in the garden of your main house. Class 3 of the Council Tax (Exceptions to Higher Amounts) (Wales) Regulations 2015 exists to remove the premium from annexes that form part of a main dwelling, but the qualifying test is narrower than most people assume.

The Class 3 Test

The annexe must form part of, or be treated as part of, a single property containing another dwelling, and it must be used as an integral part of the main residence. Both conditions matter:

Structural connection or treatment as one unit. The council looks at how the annexe relates to the main house — is it physically attached, does it share utility services, is it banded as a separate dwelling only because of its layout? A converted garage with a shared water meter and electrical circuit stands a better chance than a detached cottage 50 metres across a garden.

Integrated family use. The annexe must actually function as part of the main household. An elderly parent living in the annexe as an extension of the family home fits. A self-contained unit let to short-term holiday guests does not.

Evidence to Prepare

• Council tax banding schedule showing both the main dwelling and the annexe
• Structural floor plans or site plans showing the physical relationship
• Evidence of shared utility supply — one water meter, one electricity supply, shared central heating
• A statement explaining how the annexe is used as part of the household

Other Classes for Specific Situations

If the annexe does not meet the Class 3 test, other exception classes may still apply:

Class 4 — Armed forces. If the annexe owner is living in MoD accommodation and the annexe would be their main home otherwise, Class 4 removes the premium. This covers both empty and second home premiums and requires a posting order or MoD occupancy agreement.

Class 5 — Caravan pitches and boat moorings. A separately-banded pitch or mooring that is unoccupied but will be used for a caravan or boat when next in use qualifies for a Class 5 exception. Second homes only.

Class 6 — Planning restriction. If the annexe (or any dwelling) has a planning condition that prevents occupation for a continuous period of at least 28 days in any 12-month period, specifies holiday-let-only use, or prevents occupation as anyone's sole or main residence, Class 6 removes the second home premium. A condition that only prevents commercial letting does not qualify.

Annexes and the Wider Council Tax Picture

If the self-contained annexe is occupied by a dependent relative aged 65 or over, with a significant cognitive impairment, or with a substantial and permanent disability, the separate Class W annexe exemption may also apply. Class 3 removes the premium; Class W exempts a qualifying annexe from the underlying Council Tax charge.

The Wales Premium Exceptions Guide covers Class 3 and the other exception classes with evidence checklists and the application process for each Welsh council.

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