Great Barn House · Essex · 2025
Design advice and a lawful development certificate for extending a converted threshing barn.
A timber-framed barn converted to a house in the 1970s, beside a Grade II listed farmhouse at Great Leighs. After an earlier scheme was refused, Heritage Unlimited redesigned the proposals within permitted development limits and obtained a certificate confirming them lawful.
Great Barn House is a three-bay timber-framed threshing barn of the late eighteenth or early nineteenth century, with a projecting midstrey and a half-hipped clay tile roof. It was converted to a house in the 1970s, keeping much of its frame. It is not listed, but the council treats it as a non-designated heritage asset, and it stands within the setting of a Grade II listed farmhouse.
A householder application for dormers, a roof gable, new windows and recladding had been refused in June 2025 on heritage grounds. The owners asked Heritage Unlimited to review the position and find a way forward. A certificate of lawful development for a redesigned scheme was issued by Chelmsford City Council in December 2025.
- Property
- School Lane, Great Leighs
- Listing
- Non-designated heritage asset; setting of a Grade II listed farmhouse
- Location
- Great Leighs, Essex
- Authority
- Chelmsford City Council
- Year
- 2025
- Outcome
- Certificate of lawful development issued
An honest reading of a refusal.
The refused scheme had been judged to disrupt the simple form of the barn and to introduce a pattern of windows that was not drawn from the frame behind it. Our advice was that those concerns were well founded, and that an appeal would take the better part of a year with poor prospects.
The more useful question was what the owners were already entitled to do. Permitted development rights had not been removed when the barn was converted, and the building is neither listed nor in a conservation area. That gave a route which did not depend on overturning the refusal.
A barn conversion extension designed from the frame, within the limits.
We inspected and photographed the building in July 2025, including the frame and roof void, and reviewed the 1970s conversion drawings. The value of the building lies in its timber frame, its plain agricultural form and its relationship with the farmhouse, and the design set out to keep as much of the frame as possible and to respect the existing rhythm of openings.
A series of sketch options followed, tested against the dimensional limits for extensions, roof alterations and porches. The dormers were redesigned to sit quietly on the roof, and the extensions kept to single-storey side additions and a modest two-storey addition to the rear, in materials to match the existing building. We then prepared the existing and proposed plans, elevations and roof plan.
A certificate, and certainty for the owners.
The application for a certificate of lawful development (25/01421/CLOPUD) was submitted on 6 October 2025 with Heritage Unlimited as agent. The certificate was issued on 9 December 2025, confirming that the side and rear extensions, two rear dormers, front porch and replacement windows are lawful.
A certificate of this kind confirms what may lawfully be built. It is not a judgement on design or heritage merit, which is why the care taken over the barn’s form and frame mattered: the limits set the envelope, and the design decided what was done within it.
What we did
Advice and design, one outcome.
Heritage Development Advice
We reviewed the refused scheme, advised against an appeal and identified what could lawfully be done under permitted development rights.
About Heritage Development Advice →Design and drawings
We prepared sketch options and the application drawings, and submitted the certificate application as agent.
About Heritage Development Advice →Refused, and unsure what to do next?
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