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Self build exemption - residential annex

There are three types of self build exemption:

  • self build exemption - for a whole house
  • self build exemption - for a residential annexe
  • self build exemption - for a residential extension

The exemptions apply to anybody who is building, or commissioning, their own home, residential extension or residential annex. Individuals claiming the exemption must own the property and intend to live in it as owner-occupier for a minimum of 3 years following completion.   

Residential annex

You can apply for exemption from CIL if you are building a residential annex. You must have a material interest in the main dwelling (own or have a leasehold or seven years or more) and use the house as your main residence for three years after completion to obtain exemption. Any annexes must be built within the curtilage of the main residence and comprise one new dwelling. Any extensions must be an enlargement to the main dwelling.

Claims for self-build residential annex exemption should be submitted on CIL Form 8, which can be found using the link below.


You must also assume liability and submit a commencement notice prior to development starting.

Important Note

It is important that you don't begin work until you submit your application for exemption and you receive notice from us with a decision.  If you start any work, including digging foundations, your application for exemption will be refused.

If you fail to submit a commencement notice before starting any work, then we will charge the full amount for CIL.

If you receive exemption and then use the main house for a purpose other than a single dwelling, let out the annex or the main residence, or sell either the main dwellings or the annex separately from the other, then you will be charged the full amount for CIL. CIL is registered as a land charge and so if any of these disqualifying events occur within three years from the date of completion we can revoke exemptions and the levy will then be due.

We can also impose surcharges in addition to the full CIL charge.

Disqualifying events

Where relief is applied, the CIL chargeable amount, and amount of relief granted, will be kept on the land charges register for 3 years following completion.

If a disqualifying event occurs, you must notify the Council in writing within 14 days. If this is not done, a surcharge will be applied in addition to the levy. A copy of the notification must be sent to all owners of material interests in the relevant land.  Where the necessary evidence is not supplied on completion, the Council will give you at least 28 days to submit the forms and evidence before taking further action.


You have the right to appeal against a grant of exemption under Regulation 116A and 116B. Appeals should be made to the Valuation Office Agency. Further information can be found through CIL Appeals.

State aid

Self build exemptions cannot be granted if they would constitute a notifiable state aid.


Level 3 Privacy Notice: How we handle your data

We will use the information you provide to us to administrate the CIL liability relating to your development. As CIL has been adopted by the Council, this information is required by law.

For further information as to how we handle your data, please see the Level 2 CIL Privacy Notice. Hard copies are available on request. If you would like to discuss this notice, or how we will use your personal data, you can contact the CIL Officer via CIL@westlancs.gov.uk or on 01695 585171.