House extensions in Lewes
Extensions that respect Lewes’s historic streets and work within the South Downs National Park’s planning rules.
Building in a historic town
Lewes has more historic buildings than most towns its size: medieval and Georgian houses along the High Street, flint walls and narrow twittens running down the hill, Victorian terraces towards the station and the Pells, and twentieth-century estates such as the Nevill on the western side. An extension here has to suit the house and the street. That usually means careful choices on brick, flint, tile and timber, and a scale that does not overpower the original building.
For terraced houses, a modest single-storey rear or side-return extension is often the most realistic way to gain a proper kitchen or family room. Larger semis and detached homes have more options. Rooflights and glazed links can bring light into deep plans without adding bulk.
Call Josh on 07518 403458 (Mon–Fri, 7:30am–6pm) or send us your details through our contact form. Quotes are free and without obligation.
Get a free quote in Lewes
Planning in Lewes: the South Downs National Park
Lewes town is inside the South Downs National Park, so the National Park Authority is the planning authority. Since 1 April 2026, planning applications in Lewes District have been handled directly by the National Park Authority, which has a planning team based in the town, rather than by Lewes District Council on its behalf. Building control is still provided by Lewes District Council.
Permitted development rights for extensions are more limited in National Parks and conservation areas, and much of central Lewes is a conservation area, so more extensions here need a planning application than in Mid Sussex towns. Listed buildings need listed building consent for alterations as well. Allow for that in your timetable.
Ground, flooding and neighbours
Lewes sits where the River Ouse cuts through the Downs. Higher parts of town are on chalk, while lower areas near the river have softer ground, and some streets are in flood zones. If your home is in a flood zone, a planning application for an extension may need a flood risk assessment, and the design may need raised floor levels or flood-resilient details. Foundations are designed for your site.
Terraced and semi-detached houses share walls, so the Party Wall etc. Act 1996 often applies. All extensions also need Building Regulations approval, with inspections through the build.
How we work
We are based in Hassocks, a short drive west along the foot of the Downs. We start with a free visit and quote and an honest view on what is likely to need consent. Then we build: groundworks, the shell and roof, opening into the house, and the fit-out and finishes by our own team. Flint is a traditional Sussex material, and our flint walling and hard landscaping can help finish the outside of a project so it sits naturally among older buildings.
Frequently asked questions
Who decides planning applications in Lewes?
The South Downs National Park Authority. Since 1 April 2026 it has handled planning applications in Lewes District directly, with a team based in the town.
Who handles building control in Lewes?
Lewes District Council provides building control in the district, or you can use a registered building control approver.
Can I extend a listed building in Lewes?
Sometimes, but you will need listed building consent as well as any planning permission, and the design will need to respect the building’s historic character.
Is my home in a flood zone?
The Environment Agency’s flood map for planning shows flood zones by address. If you are in one, a flood risk assessment may be needed with your application.
Talk to us about your project
Call Josh on 07518 403458 (Mon–Fri, 7:30am–6pm) or send us your details through our contact form. Quotes are free and without obligation.
Related pages
Your next chapter
starts with a conversation.
Tell us what you have in mind. Let’s build it together.