Lawful Development Certificate in London

The rear extension limits an LDC must respect

Take the single-storey rear extension first. Under Class A the extension may reach 3 m (attached) / 4 m (detached) beyond the original rear wall, single storey. It may not be taller than 4 metres.

Other limits catch people out. Eaves near the boundary are capped, and the sum of all outbuildings and additions cannot cover more than half the curtilage. A two-storey rear extension has its own tighter depth rule and a minimum distance from the rear boundary. The table below quotes each limit with its paragraph of the Order.

Our survey measures the original house, not the house as it stands today. That distinction decides the allowance, and it is the first thing a case officer checks against historic mapping.

Lofts, side extensions and the volume allowance

A loft conversion under Class B is measured by added roof volume, with a lower allowance for terraced houses than for detached and semi-detached ones. The table gives the exact numbers. Roof extensions may not extend beyond the plane of the principal elevation facing the highway.

Side extensions are narrower: single storey, limited in height, and no wider than half the original house. If your plans stack an extension, a dormer and a porch, we add the volumes and areas on one sheet so the total is plain before you apply.

When a project breaks one limit by a small amount, the LDC route closes. We then say so at the quote stage and move to a householder planning application or, for deeper rear extensions, prior approval.

Where permitted development does not apply

Three situations remove or reduce the rights. In a conservation area or other article 2(3) land, the rules stop side extensions, cladding and rear extensions of more than one storey. Where an Article 4 direction applies, the council has withdrawn specific rights locally. And flats have none of the Part 1 rights at all.

The government's technical guidance for householders predates later changes to the Order. When the guidance and the Order differ, the Order prevails, so we draw to the Order.

That is why our first step is a free constraints check on your address. For a borough with many conservation areas, read how Camden's local rules change the route.

Fee, timing and the drawings we submit

The council's fee for a proposed-use certificate, from the current fee table: Half the normal planning fee (householder: £274). The council takes that payment directly, separate from our fixed fee, and your quote shows the amount.

The set normally includes a location plan, a block plan, and existing and proposed floor plans, elevations and section drawings, each to a stated scale with north shown. For an LDC the drawings carry more weight than in a planning application, because the officer decides on them alone. A dimension left off can cost weeks.

The extension's depth and height are modelled once, so they read the same on every sheet. Another technologist, with no hand in drawing the set, proofreads it against the Order before submission, and the sheets usually reach you roughly seven days after we measure the house.

What happens if the council disagrees

A refusal of an LDC is not a refusal of permission. It means the council does not accept that the work is lawful on the evidence given. You can add missing information, redraw within the limits, or apply for planning permission instead.

If you wish to challenge the decision, a certificate refusal can be appealed. Our planning appeals team assesses whether the officer applied the Order correctly before you spend anything on an appeal.

We do not promise a result. Our answer is careful drawing to the Order and clear evidence of the original house; if the officer wants amendments, we make them without a further fee.

After the certificate

A certificate answers the planning question only. Building Regulations still apply to the same work, so the next step is usually our building regulations drawings. If the structure is unusual, add structural calculations.

The technical sheets are drawn from the same survey and model as the certificate set, so you do not pay for a second survey. Party wall notices may be needed if you build on or near the boundary, and our handover notes flag them.