Mansard roof drawings in Kensington and Chelsea

Notting Hill and Holland Park: terraces and villas

Many Ladbroke terraces follow the contours of the hill so that parapets stay continuous, and terrace ends were often designed to look like symmetrical detached villas. A mansard on such a terrace has to keep that continuity, and the Ladbroke appraisal names the opposite as a fault. Poorly designed roof additions and additions that harm an established roofline are listed as negative features. Our Notting Hill guide sets out the rest of the area's controls.

Holland Park's appraisal is just as specific. Unsympathetic roof extensions and smaller changes such as rooflights or infilling between chimney stacks are called harmful. The point to take from it is that small roof details count as harm, so chimney stacks and rooflights go on the drawings too. The Holland Park guide has the conservation-area context.

Chelsea and Knightsbridge: the unbroken parapet

The Cheyne Conservation Area Appraisal (adopted 30 January 2017) gives an example of what goes wrong. An out-of-character roof extension to a house wing is cited as harming the group and the street. See Chelsea's period terraces for the area's other design points.

Westminster's audit for the Knightsbridge conservation areas makes a related point for the terraces on its side of the boundary. Terraces with an unbroken parapet line are unlikely to accept roof extensions, as they would disrupt group unity. The Knightsbridge guide explains which council reads which house.

Listed houses, Article 4 and Class AA

The council publishes 84 Article 4 directions and Historic England records 1,350 list entries in the borough, so a mansard here often sits inside a second or third layer of control. A listed house needs consent as well as permission: see listed building consent drawings in Kensington and Chelsea.

Permitted development does not offer a way round. Class AA is not available on article 2(3) land, and Class B requires the original eaves to be maintained or reinstated, which a parapet-fronted mansard normally removes.

Shared walls, the stair and the money

A terrace mansard rests on walls shared with both neighbours, so the notice period shapes your programme. Party structure notice at least 2 months before work. On fire, the national guidance for a storey added at this height reads: 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). In a narrow stucco terrace that route decides where the new stair can land.

Two charges apply. The council takes £548 for a householder application, and our drawings start at £845 including VAT, read by a second chartered technologist before they go out.

A new lower floor is a separate scheme, covered by basement conversion drawings in Kensington and Chelsea.