Heritage Impact Assessment FAQ
The questions below are the most commonly asked by applicants commissioning a Heritage Impact Assessment for the first time. Each answer is calibrated to the December 2024 NPPF and the 2026 fee market.
How long does an HIA take to produce?
Two to three weeks elapsed for a Grade II moderate case. One week for a one-page Heritage Statement. Six to ten weeks for a Grade I case with site visit, archaeology DBA and pre-app meetings.
Can I appeal a refusal that cites inadequate HIA?
Yes. The standard route is a Section 78 appeal to the Planning Inspectorate. Inspectors will weigh the HIA evidence afresh, so the strength of the original document is the principal determinant of appeal success. A weak HIA at application stage is hard to rescue on appeal.
Does the LPA accept retrospective HIAs?
Yes, where the works require retrospective consent. The HIA must address actual works done, identify any harm caused, and propose remediation. Retrospective HIAs are routinely required after unauthorised listed-building works; they should be commissioned before the LPA initiates enforcement.
Do I need a new HIA for a revised application?
Usually a revised HIA, not a new one. The revision should track the design changes against the original significance and impact analysis. Where the revision is material (different scope, additional demolition), a full re-write is warranted.
Will Historic England review my HIA?
Only where the asset is Grade I, Grade II* or scheduled, or in WHS buffer zones, or where the LPA refers a Grade II case to HE for advice. For most Grade II cases the LPA conservation officer reviews without HE involvement.
Is VAT charged on consultant fees?
Yes, at the standard rate (20% as of 2026), unless the consultant is below the VAT registration threshold. Sole-practitioner IHBC consultants below the threshold are exempt; most established consultancies charge VAT.
Can I commission an HIA from outside the UK?
Technically yes; in practice no. LPA officers expect named UK-credentialled authors (RIBA-CA, IHBC, CIfA, RICS-BCA). Cases authored from outside the UK are routinely returned for further information.
What is the difference between a Heritage Statement and a Design and Access Statement?
A Design and Access Statement covers design choices, access and amenity. A Heritage Statement covers significance, harm and mitigation under NPPF heritage paragraphs. Both are usually required for a listed-building application; one does not substitute for the other.