How does the CIL self-build exemption work?

Who qualifies

Self-build housing is a dwelling built by P (including where built following a commission by P) and occupied by P as P's sole or main residence.

You do not have to lay the bricks. A house built by a contractor to your commission qualifies if it becomes your main home, and the planning practice guidance adds that you must own it. Homes built to sell or to let do not.

The procedure, in order

1. Planning permission and liability notice. The council issues a liability notice as soon as practicable after permission first permits the development (regulation 65(1)). It states the chargeable amount (regulation 65(2)(d)), which is what you pay if the exemption is not secured.
2. Assume liability. Send Form 2, Assumption of Liability (regulation 31). If someone else has already assumed liability, the self-builder takes it over on Form 4, Transfer of Assumed Liability. The claim is only valid from a person who "has assumed liability to pay CIL in respect of the new dwelling" (regulation 54B(2)(a)(ii)).
3. Claim on Form 7 Part 1. It must be received by the council before the development commences (regulation 54B(2)(b)). On it you self-certify that you will occupy the home as your principal residence for three years from completion.
4. Wait for the written decision. If work starts before the council notifies you of its decision, the claim lapses (regulation 54B(3)).
5. Send the commencement notice, Form 6, no later than the day before work starts (regulation 67(1)). The notice must state the intended start date. If it is missing, the council must impose a surcharge of 20% of the CIL that would have been payable, or £2,500 if lower (regulation 83(1A)). The exemption survives, where the liability notice was issued on or after 1 September 2019.
6. Build, and get the compliance certificate. This means a completion certificate under regulation 17 of the Building Regulations 2010 or a final certificate under section 51 of the Building Act 1984 (definition in regulation 2(1)).
7. Send Form 7 Part 2 within six months of the date of the compliance certificate (regulation 54C(2)), with the evidence listed below.
8. Live there for three years. The clawback period runs for three years from the date of the compliance certificate (regulation 2(1)).

Within six months of the date of the compliance certificate for D, P must submit a form to the collecting authority confirming that D is self-build housing or self-build communal development (as the case may be).

The evidence for Part 2, from the planning practice guidance (paragraph 088) and the form itself:

• the compliance certificate;
• title deeds, freehold or leasehold;
• a council tax bill or certificate, and two further proofs of occupation (a utility bill, bank statement or electoral roll entry);
• one of: an approved HMRC claim under VAT431NB (VAT refunds for DIY housebuilders), a self-build warranty, or a self-build mortgage.

The council has discretion to accept other evidence in place of the last item. The guidance says to agree that in advance, at the Part 1 stage or soon after.

What goes wrong

More on these traps, and the government's June 2026 letter about them, is in how householders lose CIL exemptions.

The annex exemption

A residential annex, one new dwelling wholly within the curtilage of the house you own and live in, has its own exemption (regulation 42A(2)). You claim it on Form 8 before work starts (regulation 42B). Unlike an extension, an annex still needs a commencement notice before work starts (regulation 67(1A) does not cover it), and missing it brings the same surcharge (regulation 83(1A)). The exemption is withdrawn if, within three years of the annex's compliance certificate, the main house is used other than as a single dwelling, the annex is let, or either is sold separately from the other (regulation 42C). See also annexes and CIL on an extension.

What this means for you

Most of the conditions are about timing. Put the four forms (2, 7 Part 1, 6 and 7 Part 2) into the programme with their deadlines before a start date is fixed, and keep proof of when each one was received.

Parallel carries out site appraisals and planning applications for new homes. The CIL position, and the order in which the forms must go in, is one of the things to settle before work is programmed.