Hip-to-gable loft conversion drawings in Hammersmith & Fulham

Housing mix: why hip-to-gable is a niche here

Only 24.6 per cent of households in the borough live in a house or bungalow, in the latest Census. Most homes are flats, and flats never carry householder roof rights. A hip-to-gable job is therefore a specialist piece of work for the minority with a hipped house, which is why we start by confirming the property is a single dwelling.

Those houses are valuable. The average semi-detached sale price is £1,503,460, so owners tend to weigh a loft carefully against moving. Good drawings show the extra floor area and the stair before money is spent on a builder.

Permitted development or planning for your roof

The national route is Class B, and the order states the volume allowance as 40 m³ (terrace house) / 50 m³ (any other house) additional roof volume. Hip-to-gable work has a carve-out: Eaves-retention and 0.2 m set-back conditions do not apply to a hip-to-gable enlargement. Two limits still apply: No enlargement beyond the plane of a roof slope that forms the principal elevation and fronts a highway, and No part of the enlargement may extend beyond the outside face of any external wall of the original house (except where joining a rear or side extension roof).

Inside a conservation area the position reverses, because Class B roof enlargements are not permitted development on article 2(3) land. A Lawful Development Certificate in Hammersmith & Fulham is the written proof for houses that qualify, and the borough dealt with 94 certificate applications in its latest published year. Houses that do not qualify go through planning drawings in Hammersmith & Fulham.

How the council has handled householder cases

The borough decided 506 householder applications in its latest year and granted 97.8 per cent of them. Timing is the weaker figure: only 79.8 per cent were decided inside eight weeks or an agreed extension, so we advise clients to plan for a wait.

These figures cover every householder project, from porches to basements, so they say little about a roof alone. We use them for scheduling, never as a prediction.

Stair, fire route and the technical sheets

The stair settles most hip-to-gable designs. Where full height cannot be reached, the rule is Loft conversions where 2.0 m cannot be achieved: 1.9 m at the centre of the stair, 1.8 m at the side (half width). On terraced-style plots the landing often has to sit directly over the existing stair, and the gable end is what finally makes that possible.

A new storey also triggers a protected escape route: New storey above 4.5 m by loft conversion: protect the full escape route with fire-resisting doors (min E 20) and partitions (min REI 30). Both points go onto the Building Regulations set, which our building regulations drawings in Hammersmith & Fulham page explains.

Surveying a Hammersmith & Fulham roof

Roofs vary from street to street, in pitch, covering and eaves depth. We survey the ridge, eaves, hip rafter and the chimney stacks on the shared wall, because a stack on the flank decides whether a gable can rise cleanly or must wrap around it.

The survey also records what the neighbours have done. A gable already built next door, a rear dormer across the road or a mansard on the end of the terrace all show what has been accepted nearby, and we place them on a short context sheet. It is evidence for the planning officer and a sanity check for you.

From the survey we produce existing and proposed plans, roof plan, elevations and a section through the new stair. After you pick an option in writing the design is frozen, and a second chartered technologist checks every sheet before it leaves us. Price comes as one fixed quote, with VAT included, so there is no meter running while the officer asks questions.

Pairing it with a dormer, and nearby boroughs

Most owners want a rear dormer behind the new gable. Drawing both in one Revit model keeps the volume figure honest, and our dormer loft conversion drawings in Hammersmith & Fulham page covers that half. For the wider choice of roof routes see loft conversion drawings in Hammersmith & Fulham.

Over the border the rules shift. Our hip-to-gable loft conversion drawings in Kensington and Chelsea and in Hounslow show how those councils approach the same roof, and the general picture is on the hip-to-gable service page. Everything we cover locally sits under architectural drawings in Hammersmith & Fulham.