Daylight and sunlight report in Harrow

Suburban plots and the gardens behind them

Here 65.4 per cent of households live in a house or bungalow and 58.8 per cent own their home. Gardens are long and light reaches the rear windows from a wide angle. That is the reason most householder schemes pass without a study: the geometry is generous.

The cases that cause trouble are narrower. A two-storey rear extension on a short garden, a loft with a deep dormer on a pair of semis, or an outbuilding on the boundary beside a neighbour's patio doors can still cast shade. Our Harrow checks concentrate on those, using the neighbours' actual window positions.

Residential Design Guide and the new Local Plan

The council's design reference for extensions is the Residential Design Guide SPD. It sits under the Harrow Local Plan 2021-2041, adopted in 2,026. A recently adopted plan means the policies officers cite are fresh, so a report drawn up to older assumptions risks missing the current wording.

We build the study around the guide's own tests for neighbouring amenity, and cite the plan policy by name in the written conclusion. That makes it easy for the case officer to follow the reasoning and tick the box.

Heritage and Green Belt on the edges

Not every Harrow plot is simple. The borough has 31 conservation areas, 295 Historic England list entries and about 22 per cent of its area under Green Belt. A scheme in a conservation area often has to hold the existing ridge height, while a Green Belt site limits how much floor area can be added, so the form of the building is often fixed before light is considered.

In those cases the light study confirms that the form the policy allows is acceptable next door. It is evidence in support rather than a hurdle.

What the decision statistics suggest

Harrow decided 917 householder applications in the latest published year and granted 81.7 per cent, with 93.7 per cent decided in time. Minor schemes tell a tougher story: 60.4 per cent of 341 decisions were granted. Minor schemes include small new homes and conversions, the types most likely to carry a light statement.

Take these as background. They say nothing about any single address, and they include every kind of reason for refusal, not only light.

Statements for flats and infill

For a block of flats or an infill house, the statement is a fuller job. We model the proposed building beside its neighbours, run the vertical sky component and sunlight tests on the affected windows, and add a shadow study for gardens and shared amenity space. The conclusion is written for the officer, and the figures sit in an appendix so that anyone checking the work can trace each result back to a window.

Next steps and related pages

To understand the tests in more detail, see our guide to daylight and sunlight reports. The drawings that accompany a Harrow application are covered under planning drawings in Harrow, and the borough page is architectural drawings in Harrow. Plots near the boundary may fall under Brent or Barnet, which apply their own lists.

We quote once we have seen the address, and the figure we agree stays as agreed.