Wraparound Extension Drawings in Harrow on the Hill HA1
Fixed-fee, MCIAT-chartered wraparound extension drawings for Harrow on the Hill (HA1) homeowners — London Borough of Harrow validation and local constraints handled from the start.
Harrow on the Hill (HA1) is built around a steep historic village on the ridge above the town, where the High Street, Church Hill and West Street keep their Georgian and early-Victorian character alongside the Harrow School buildings. Householder work here is dominated by careful rear and side extensions and internal reconfiguration rather than visible roofline changes.
The Harrow on the Hill Village Conservation Area was designated in 1968 and carries a revised Article 4 Direction, so window, door, roof and boundary changes that would be permitted development elsewhere need a planning application here. We check where a property sits relative to the village and Mount Park Estate boundaries before advising a route.
Planning in Harrow on the Hill (HA1): what to know before you apply
Because the village core is both a conservation area and covered by an Article 4 Direction, many HA1 houses on and near the hill have lost the permitted-development rights that similar homes elsewhere in Harrow retain. Rear extensions kept out of the protected street views, and interior remodelling, are usually the most deliverable projects; roofline and front-elevation changes attract close conservation scrutiny.
Typical Harrow on the Hill housing stock
The hilltop village around the High Street and Church Hill mixes Georgian and early-Victorian houses with the Harrow School estate, giving way to substantial Edwardian and inter-war villas on the Mount Park Estate and South Hill Avenue below.
Streets we regularly draw for in Harrow on the Hill
High Street · West Street · Church Hill · Grove Hill · Mount Park Road
Wraparound Extension Drawings for Harrow on the Hill (HA1) homes: the package and the process
Every wraparound extension drawings we prepare for an Harrow on the Hill property is drawn to London Borough of Harrow’s validation standards and tuned to the HA1 constraints above. Here is what the drawing package covers and how the process runs from first survey to approval.
A wraparound extension is what happens when a rear extension and a side return are designed together rather than as two separate projects: the new build wraps around the back corner of the house, turning a galley kitchen and a small rear room into one continuous kitchen, dining and living space running the full width of the plot. It is the most ambitious single-storey option most London terraces and semi-detached houses have, and because it reshapes almost the entire ground floor, it needs careful structural and drainage planning as well as a confident planning application.
DrawingsDirect draws wraparound extensions for full planning and building regulations, with structural calculations for the L-shaped frame and any drainage diversion produced in-house by our MCIAT-chartered team, on a fixed fee. If your project is a single-storey rear addition or a side infill on its own, see our Rear Extension and Side Return Extension pages; if you also want a second storey, see Double Storey Extension Drawings.
What makes a wraparound extension different from a rear or side return alone?
A rear extension adds depth at the back of the house; a side return adds width down the alley; a wraparound does both at once, so the new floor area turns the corner of the original building rather than sitting against just one wall. The result is typically the largest open-plan space a single-storey extension can deliver, but it also means more of the original external wall is removed and more of the roof is new, which raises the structural and drainage stakes compared with either extension on its own. Homeowners who start out planning a rear extension or a side return alone often move to a wraparound once they see how little extra it costs to combine the two, since much of the groundwork, roof structure and glazing is shared between them rather than duplicated.
Do wraparound extensions need full planning permission in London?
Almost always, yes. Permitted development allowances are calculated on combined additions to the original house, and a wraparound's depth plus width together generally exceed the volume and footprint limits that apply to a rear extension or side extension considered separately. A Lawful Development Certificate route is rarely viable for a genuine wraparound.
Conservation area status and Article 4 directions, common across the terraced streets where wraparound extensions are most popular, remove permitted development rights further still, so we design every wraparound on the assumption it will go through full householder planning.
| Route | What it covers | Typical fee |
|---|---|---|
| Full planning permission | Required for almost all wraparound extensions given the combined footprint | Full Planning pack ~£1,600–£2,400 |
| Planning + Building Regulations (structural) | Combined pack including structural calculations for the L-shaped frame and drainage diversion | Planning + Building Regs pack ~£2,200–£3,850 |
| Rear extension alone (comparison) | Smaller single-storey addition, may qualify for permitted development | see Rear Extension Drawings, from £1,100 |
| Side return alone (comparison) | Widens the kitchen only, keeps garden depth unchanged | see Side Return Extension Drawings, from £1,400 |
Wraparound Extension Drawings in Harrow on the Hill HA1 — FAQs
How much does a wraparound extension cost to design in London?+
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