Self-build exemption from the infrastructure levy

The self build CIL exemption is one of the few reliefs in the planning system that is worth real money to an individual, and it is lost through paperwork far more often than through ineligibility. The sequence is unforgiving: claim, grant, notify the start date, then begin. Start work a day early, or before the claim has been granted, and the exemption is gone with no route back.

One clarification before the detail. The regime in force is the Community Infrastructure Levy, under the Community Infrastructure Levy Regulations 2010 as amended. The Infrastructure Levy in the Levelling-up and Regeneration Act 2023 has not been brought into force. As at September 2026 the 2010 Regulations govern these claims, and the position should be checked on legislation.gov.uk before relying on it.

Which exemptions exist for self-builders

Four provisions matter to anyone building their own home:

• The self-build exemption, for a dwelling built or commissioned by an individual who will occupy it as their sole or main residence for at least three years after completion.
• The residential annexe exemption, for an annexe within the curtilage of your own dwelling.
• The residential extension exemption, for an extension to your own dwelling.
• The minor development rule, under which new build of less than 100 square metres of gross internal area is not liable at all, provided it does not comprise a dwelling.

That last one catches more cases than people realise. A 70 square metre extension is outside the levy without any claim, and the paperwork only becomes necessary once the floorspace reaches 100 square metres or a new dwelling is created.

Liability arises only where the charging authority has adopted a charging schedule, and rates vary by area and by development type within the same district. Check the schedule for your site before you calculate anything, and check its indexation date, because rates are indexed annually.

The forms and their sequence

For a self-build dwelling, in this order:

1. Submit the additional information form with the planning application, so the authority can determine liability.
2. Assume liability, using the assumption of liability form, in the name of the individual who will occupy the house.
3. Submit part 1 of the self-build exemption claim, and wait for written confirmation that it has been granted.
4. Submit the form notifying the authority of the date development will start, at least the required period in advance.
5. Start work, and not before step 3 is confirmed and step 4 has been received.
6. Submit part 2 of the self-build exemption claim within six months of completion, with the evidence.

Steps 3 and 4 are where exemptions die. A claim that has been submitted is not a claim that has been granted, and the authority is entitled to treat work started before the grant as chargeable development at the full rate, with surcharges added.

Keep the receipts for every submission. Portal acknowledgements, email confirmations and dated letters are what settle a dispute about whether the authority received something, and the burden of proof sits with you.

Assuming liability before work starts

Assumption of liability sounds like an odd thing to do when you intend to claim an exemption, and it is a condition of the exemption route. The regulations work by identifying a liable party and then relieving that party, so somebody has to be liable first.

Assume liability in the name of the individual who will live in the house. Not a company, not a spouse who will not be on the title, not the builder. Where a couple will own and occupy jointly, follow the authority's practice on joint claims and ask in writing rather than guessing.

Then serve the notice of the start date. The regulations set a minimum period of notice, and it is short, so this is the item most likely to be forgotten in the week the groundworker becomes available. Diarise it alongside the building control initial notice.

The occupation period and clawback

Part 2 of the claim is the piece most often missed, because by the time a house is finished nobody is thinking about levy paperwork. It has to be submitted within six months of completion, and completion means the date on the building control completion certificate.

The evidence required is specific:

• The building regulations compliance or completion certificate.
• Title deeds showing ownership of the dwelling and the land.
• Evidence of council tax liability at the property.
• At least one of a specialist self-build warranty, an approved self-build mortgage, or an accepted claim under the VAT scheme for building a new home.

Then the three year clock runs from completion. Selling the dwelling, letting it, or otherwise ceasing to occupy it as your sole or main residence within that period is a disqualifying event, and the exempted levy becomes payable. Inheritance and certain other transfers are treated differently, and if anything unusual is proposed, ask the authority in writing before doing it.

Illustrative example. A self-builder completes a four bedroom house in a district with an adopted charging schedule. The exemption was claimed and granted before the groundworks started, the start notice went in with eight days to spare, and part 2 was submitted three months after the completion certificate with the warranty and council tax evidence attached. Two years later the family decides to move. Because the move falls inside the three year period, the levy that was exempted becomes payable, and the sale has to be priced with that in mind. Nothing has gone wrong procedurally, and the liability is still real.

Annexes and extensions treated separately

The annexe and extension exemptions are simpler, with the same structural trap. Claim before work starts, obtain the grant, and notify the start date.

An annexe exemption has its own three year period and its own disqualifying events, which centre on the annexe being let or sold separately from the main dwelling. In practice this is what catches people who build an annexe for a relative and later let it out as a separate unit. It also matters whether the annexe is ancillary to the house rather than a separate dwelling in planning terms, since a separate dwelling is a different proposal with different levy treatment.

For extensions, check the floorspace first. Below 100 square metres of new build that is not a dwelling, there is no liability and no claim to make. At or above it, the exemption is available for an extension to your own home and worth claiming properly.

Mistakes that lose the exemption entirely

The pattern is consistent, and each one is avoidable:

1. Starting work before the claim has been granted.
2. Not serving the notice of the start date, or serving it late.
3. Assuming liability in the wrong name, most often a limited company.
4. Missing the six month deadline for part 2 after completion.
5. Treating the building control completion certificate as optional evidence.
6. Selling or letting inside the three year period without budgeting for the clawback.
7. Assuming that because the council never issued a liability notice, there is no liability. Ask.
8. Mistaking the levy for a section 106 obligation, and being surprised by the other one.

The appeal routes are narrow. Disputes about the chargeable amount go to the Valuation Office Agency, surcharge appeals go to the Planning Inspectorate, and neither of them can restore an exemption lost by starting work early. This is a regime where procedure beats merit.

Put the levy position in the Planning Statement or the covering letter at application stage, naming the charging schedule and the exemption you intend to claim. It signals to the case officer that the additional information form and the claim will follow, and it gives you a dated record of your own intention. Where a scheme is large enough to engage affordable housing policy as well, the Affordable Housing Statement and the levy position should be read together, because obligations and levy are charged on different bases and both land on the same budget.

This is general guidance, not legal advice; check the position with your local planning authority or a qualified professional before relying on it, and read the current version of the Regulations before making a claim.

PlanScope drafts the supporting statements for a self-build application from your site data, and what a draft report costs is set out plainly, with one free report, £50 per report or the Professional tier at £150 per month. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.

Enter your plot postcode on PlanScope to see which of the reports your project needs apply before you start the levy paperwork.