Basement
conversions
in Muswell Hill, N10

Haringey's Policy DM18 permits a new or extended basement only where the house and its neighbours stay stable, flood risk does not rise and the area's character is not harmed.

We say early, and plainly, when a site makes a basement a poor idea, and look at the loft or a rear addition instead.

Source: Haringey Council: Development Management DPD (Haringey Local Plan, adopted July 2017)

Haringey reports a rise in basement applications and wants them built without harm to neighbours, adjoining houses, flood risk or the area's character.

The tests run through stability (of the house, its neighbours and the highway, given the local geology), flood risk from any source, and the look of the property and the street.

We prepare the case against each test in turn, with the engineer's and the hydrologist's reports attached.

Source: Haringey Council: Development Management DPD (Haringey Local Plan, adopted July 2017)

For a light well, Haringey weighs the building's character, the street and whether more than half the front garden would be lost.

It warns that light wells can harm a street where they are not already an established feature.

Small front gardens behind low walls are, in Haringey's words, an essential part of how these frontages were designed to meet the street.

At the front we look at a grille set into the path or a rear light well, rather than an open pit in the garden.

Sources: Haringey Council: Development Management DPD (Haringey Local Plan, adopted July 2017), Haringey Council: Muswell Hill Conservation Area Character Appraisal (Conservation Area No. 3, adopted 11 February 2008)

A Basement Impact Assessment, by qualified independent assessors and paid for by the applicant, goes in with the application.

Haringey runs a separate householder advice service for a property with a basement, and can arrange advice on site.

We commission the assessment early, so its findings shape the design rather than arrive after it.

Sources: Haringey Council: Development Management DPD (Haringey Local Plan, adopted July 2017), Haringey Council: Planning advice services for householders

DM18 asks basement construction not to endanger road users or unreasonably disrupt neighbours, and to keep noise, vibration and dust down.

Each skip licence lasts no more than 28 days and must be sought five working days before it starts.

Scaffolding or hoarding on the pavement needs a Haringey licence.

Breaking out and piling stay inside Haringey's hours for noisy work, which start at eight and end at six on weekday evenings and at one on Saturday afternoons.

Sources: Haringey Council: Development Management DPD (Haringey Local Plan, adopted July 2017), Haringey Council: Skip/building materials licence, Haringey Council: Scaffolding, hoarding, container and crane licences, Haringey Council: Noise complaints

Haringey points out that, in a conservation area, an application can fail on conservation grounds alone.

Where a basement affects a heritage asset, the application must explain what makes the asset significant and how the excavation would change it.

Our heritage statement for a basement shows the front elevation before and after, the light well or grille drawn to scale, and the garden levels that the neighbours will see.

We also show what would be lost from the garden and how the planting will be put back over the roof of the new rooms.

Sources: Haringey Council: Planning permission in conservation areas, Haringey Council: Development Management DPD (Haringey Local Plan, adopted July 2017)