An extension in Letchworth Garden City can need two separate approvals from two separate bodies. We survey, appoint a structural engineer, coordinate the planning and building control applications, and build the shell, the roof and the internal work. We never produce structural calculations. This page sets out both approval routes, the design tests your drawings are judged against, and the ground conditions.
The planning test your extension is judged against
Policy D2 of the adopted North Hertfordshire Local Plan grants permission for house extensions only where two tests are both met. The extension must be sympathetic to the existing house in height, form, proportions, roof type, window details, materials and the orientation of the main dwelling. It must also not dominate adjoining properties.
The local planning authority is North Hertfordshire District Council, working to the North Hertfordshire Local Plan 2011 to 2031, adopted on 8 November 2022. Those tests are design questions settled on the drawing, which is why the designer is appointed and the scheme resolved before anything is priced as a build.
Heritage Foundation consent is a second application, and it is free if you apply first
Applying to the Heritage Foundation before doing the work is free. A retrospective application covering up to three alterations costs £216. The Foundation aims to process an application within six weeks once it has been registered and assigned to a case officer. Timescales extend where more information or changes are asked for, or where the case is referred to the Householders Applications Committee or the Board of Trustees.
It is worth being clear about where that control comes from. There is no Article 4 direction anywhere in Letchworth. North Hertfordshire has only two, both made on 9 October 2012, and they cover the Hitchin and Stockens Green conservation areas. The Letchworth constraint is the Foundation's, and it runs on its own timetable alongside the council's.
Which design principles apply depends on your character area
The Heritage Foundation splits Letchworth into Heritage and Modern character areas, each with its own Design Principles, and homeowners are asked to check which applies to their property before applying. That check belongs at the sketch stage, not after the drawings are finalised.
The Letchworth Conservation Area Appraisal describes off white and cream roughcast walling as the predominant walling finish within the conservation area. It also names garages or extensions enclosing the spaces between buildings as a change that harms the character of the Cheap Cottages Exhibition streets. A side infill on one of those streets is therefore a conversation to have early.
Flood zone and watercourses on the north west side
The Environment Agency Flood Map for. Planning shows a single Flood Zone 3 corridor in Letchworth. It follows the watercourse valley in the north west of the town and runs north from roughly the latitude of the town centre. The rest of the built up area, including the whole southern half of the town, sits in Flood Zone 1.
The Statutory Main River Map records no main river within the built up area of Letchworth Garden City, so watercourses through the town are ordinary watercourses. That changes who you deal with about anything close to a channel. We check the zone for your address before a drainage strategy is drawn, because it can affect what the planning application has to include.
- Party Wall Act notices for excavation near a neighbour's wall
- Planning applications and permitted development assessments
- Single and double storey extensions
- Full fit-out, finishing and making good
- Insulation, airtightness and thermal detailing to regulations
Why Choose GS Renovation in Letchworth Garden City
An extension here runs two approval tracks at once, and they do not move at the same speed. We coordinate the structural engineer, the planning application, and the building control application and inspections, then build the shell and the internal work with one team. That gives you one point of contact and one programme instead of a chain of separate trades. GS Renovation Ltd is a contractor: we appoint structural engineers and build to their calculations, and we never produce those calculations ourselves. Fully insured, registered in England, company number 14611254, and quotations are free and carry no obligation.
- Paperwork and certificates handed over for when you sell
- Rated 4.9 from 31 reviews on MyBuilder
- Materials priced at options, so you choose the finish
- Brick and mortar matched to the existing elevation
- Building control inspected at foundation, damp course and steel stages
- Weathertight shell reached before the fit-out begins