House extension drawings in Hammersmith and Fulham

Permitted development, prior approval or an application

On a house outside conservation land, the national rule allows a single-storey rear extension of 3 m (attached) / 4 m (detached) beyond the original rear wall, single storey, up to 4 m high. A Lawful Development Certificate in Hammersmith and Fulham gives written proof.

Prior approval allows 6 m (attached) / 8 m (detached), single storey, height max 4 m; not on article 2(3) land or an SSSI, with 42 days for the council to respond. The borough's use of it has been small: in the latest published year it granted 3 larger home extension prior approvals and refused 1. The route is unavailable on conservation land, which limits it further.

That is why many extensions here go through a householder application, drawn as in our planning drawings in Hammersmith and Fulham. The council fee is £548, paid to the council.

How the council has been deciding householder applications

The council decided 506 householder applications in its latest published year and granted 97.8 per cent, a high rate. 79.8 per cent were decided within eight weeks or an agreed extension.

A high grant rate says nothing certain about your own plans, so we treat it as context for the timetable and not as a forecast.

What the drawings include and what they cost

A set for Hammersmith and Fulham has existing and proposed floor plans, elevations and sections, plus location and block plans. Extension drawings start at £695 including VAT, fixed before you commit, and are normally ready about a week after the survey.

Each sheet is checked by a second chartered technologist, and if the council asks for changes we redraw at no charge until approval.

Terraced extensions often touch a shared wall. The Party Wall Act then applies: Adjacent excavation notice at least 1 month before work: within 3 m and deeper than the neighbour's foundations, or within 6 m and cutting a 45° line from their foundations. We can help prepare the notices with party wall notices.

The design must also meet the energy rules in Approved Document L: 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. Glazing is limited too: 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. Two exemptions apply: Residential extensions and annexes can claim exemption (claim before commencement), and Householder applications are exempt from biodiversity net gain.

Our approach is to settle the status of the building first. If it is a house outside conservation land, we test the permitted development limits and tell you plainly whether a certificate is enough. If it is a flat, or the address is restricted, we go straight to the application and draw it to the standard the council validates against.

Other extension types and nearby boroughs

To look at a single form, see rear extension drawings in Hammersmith and Fulham or side return extension drawings in Hammersmith and Fulham. The wider view is architectural drawings in Hammersmith and Fulham.

The next borough may apply a different guide. Compare house extension drawings in Ealing, in Hounslow or in Richmond upon Thames.