Basement impact assessment in Camden

Camden's heritage, trees and neighbours

Camden has 40 conservation areas, 21 Article 4 directions and 1,971 listed entries, with 1,746 at Grade II. The borough is dense with terraces of exactly the age and type where a basement is proposed, so the heritage case sits beside the ground report on almost every job.

Only 13.3 per cent of households live in a house, and 29.7 per cent own their home, so a basement is usually a single-household scheme in a street of flats, shared freeholds or leaseholds. Flat owners also need the freeholder's consent, and that conversation takes time.

Heritage at Risk lists 35 entries in the borough. Where a property is on or beside one, we flag it at the free check.

The practical effect is that Camden basements are rarely simple. A house in a conservation area needs the front elevation, the lightwell and any new railings drawn to a standard a conservation officer will read closely, while the engineer designs retaining walls that must not disturb the neighbours' foundations on either side. We keep both threads on one set of sheets, so the design that satisfies the ground study is the same design the heritage officer sees.

What the decision statistics show

Camden decided 394 householder applications in its latest year and granted 89.1 per cent. Only 77.7 per cent were decided in time, which is a reminder to plan a long programme.

The Planning Inspectorate decided 76 householder appeals against the borough and allowed 35.5 per cent. The sample is small, and it covers all householder work, not only basements.

A five-stage assessment is slower than a drawing set. The site investigation needs a drilling slot and, often, a monitoring period, so we put the ground study at the start of the programme, not after the planning drawings are done.

We also help owners prepare the non-technical summary. It should say, in plain words, how deep the basement goes, how the neighbours' walls will be protected during the dig, where the water goes, and what will be monitored. A summary a neighbour can follow can reduce objections, and objections slow any application.

Party wall, levy and Building Regulations in Camden

In streets of terraces, most basements trigger the Party Wall etc. Act. Excavation within 3 metres of an adjoining building that goes deeper than its foundations needs a notice, as does a dig within 6 metres on the diagonal test. The notice must be served at least 1 month before work.

The mayoral Community Infrastructure Levy for Camden is 96.97 pounds per square metre for permissions granted this year, and a large new basement can be liable. The borough's own schedule is the London Borough of Camden Community Infrastructure Levy Charging Schedule.

Building Regulations require drainage where the water table can rise within 0.25 metres of the lowest floor.

Price and next steps

There is no list price, because the scope depends on the site. After the free check you get a fixed quote, and the planning drawings in Camden we produce carry the sections the assessment relies on.

The borough overview is architectural drawings in Camden. Next door, Westminster works from numeric limits instead of a staged method, and the national rules are on the basement impact assessment hub.