Side return extension drawings in Harrow

How Harrow decides householder schemes

In its latest twelve-month record Harrow decided 917 householder applications and granted 81.7 per cent. 93.7 per cent were settled in eight weeks or an agreed extension.

Read those as the borough's general pattern. They say a tidy householder submission is a normal thing for the council to handle, and they say nothing about your address.

The surrounding character matters too. Domestic gardens make up 34.7 per cent of Harrow's land in the national land-use survey, so officers are used to weighing a new extension against how much garden is left behind it.

Conservation areas, listed homes and Green Belt in Harrow

The council publishes 31 conservation areas, and national permitted development gives no side extensions on land of that kind: No side extensions under PD on article 2(3) land (conservation areas etc.). If your road is inside one, the work goes in as a householder application.

Historic England lists 295 entries inside the borough, and Green Belt covers 22 per cent of its area. A listed house needs a separate consent, and a Green Belt plot is tested on how much bigger the building becomes, so we check both during the free constraints check.

Outside those designations the permitted route is narrow: Side extension: single storey, max 4 m high, max half the width of the original house. Close to the boundary the eaves have their own national cap: Eaves no higher than 3 m where within 2 m of the curtilage boundary.

Prior approval does not suit a side return

Prior approval covers deeper rear extensions, not side ones. Even so, Harrow's record on larger home extension prior approvals shows how closely neighbours' interests are weighed: 27 granted against 108 refused in the latest year.

If the scheme combines a side return with a deeper rear, a full application is usually the cleaner route. Where a smaller scheme is plainly lawful, a lawful development certificate in Harrow records that in writing.

The council's householder fee is £548, paid to the council separately from our fee.

Party walls, glazing and the building regulations

A side return almost always leans on the neighbour's flank wall. Building a fresh wall on the line calls for this: Line-of-junction (new wall) notice at least 1 month before work. Cutting into a shared structure needs: Party structure notice at least 2 months before work. Our party wall notices service prepares both from the drawings.

The roof is usually glass, and Approved Document L limits how much: Windows, roof windows, rooflights and doors in an extension should not exceed 25% of the extension floor area plus the area of openings removed or covered. New elements carry these U-values: New elements in existing dwellings, limiting U-values W/(m²·K): roof 0.15, wall 0.18, floor 0.18, windows 1.4 (or WER Band B), doors 1.4.

Taking out the old flank wall means a steel beam. The engineer's sizes go on our sheets, and the technical set follows through building regulations drawings in Harrow.

What you get and what it costs in Harrow

Existing and proposed plans, elevations, sections and the location and block plans, with the forms and Planning Portal submission if you want them. The price is £745, fixed and shown before you commit.

Before submission a second chartered technologist, not the one who drew it, goes through every sheet; should Harrow's officers want amendments, the redraw costs you nothing. The overview of our work in the borough is at architectural drawings in Harrow.