40 Wrottesley Road: Extension & Loft Conversion
40 Wrottesley Road, Brent, London NW10 5YG
Planning, Building Regulation drawings and structural drawings and calculations for side and rear extensions and a hip-to-gable loft conversion at a corner house in Brent. Under construction.
Project overview
The Project
At 40 Wrottesley Road, the side extension faces Odessa Road. Its roof and flank wall are therefore part of the street scene, as well as an addition to the house. At the rear, the extension has to work beside No. 42. These two relationships shaped the planning case for enlarging this semi-detached home in Brent.
We were appointed in 2026 for the planning and Building Regulations work. The project is now under construction, with the steelwork, new masonry and timber roof framing visible in the site photographs.
The starting point was a house with an attached garage along Odessa Road and an existing single-storey rear projection. The proposal replaces the garage with a two-storey side extension, continues that addition around the rear and adds a deeper single-storey extension. Above, a hip-to-gable conversion and rear dormer enlarge the roof space.
The extension drawings had to show how those parts fitted together. A side extension that looked acceptable from the front still needed a convincing roof form when viewed from Odessa Road. A deeper ground-floor addition also needed a different height and boundary treatment from the two-storey rear extension.
Drawings and project imagery
Project Gallery
10 presentation plates
Selected architectural drawings, technical details and project views from the coordinated design package.
Swipe to view drawings
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Planning strategy
Planning & Heritage
Why the rear extensions have different depths
At first-floor level, the side extension steps back 500 mm from the original front wall. That setback keeps the original frontage legible, while the new ridge and eaves remain within the height of the existing house.
The two-storey rear extension stops 3 metres beyond the original rear wall. Our drawings showed the nearest habitable-room window at No. 42 and the 45-degree line used to assess the neighbour’s relationship with the addition. Brent’s officer accepted that arrangement.
The ground-floor extension continues another 3 metres, giving a total depth of 6 metres. Beside No. 42, its pitched roof has an eaves height of 2.45 metres. This meets a flat-roof portion no higher than 3 metres above ground level. The extra depth is therefore kept at ground-floor level, with a low edge towards the adjoining property.
No. 42 already has a rear extension. The officer assessed the proposed ground-floor addition as projecting 3 metres beyond that existing extension and found the effect on outlook and daylight acceptable. That existing arrangement mattered to the assessment; the 6-metre depth alone does not explain the planning outcome.
Spatial design
Architectural Design
Making the gable and dormer work with the side extension
Changing the original hip to a gable affects the whole side elevation. With a two-storey side extension below it, the loft conversion needed to be considered as part of the enlarged house’s roof composition.
The planning case addressed the surrounding roof forms. During the site visit, Brent’s officer noted hip-to-gable conversions at other properties on Wrottesley Road, towards its junction with Furness Road, and accepted the proposed conversion in that context.
The rear dormer measures approximately 5.4 metres wide and 2.9 metres high in the officer’s assessment. It sits above the eaves, below the ridge and in from the new gable end. That last offset keeps the dormer separate from the side gable when viewed from the flank. Two rooflights serve the front roof slope.
The construction photograph now shows the dormer’s timber framing and OSB sheathing, with its two window openings formed beneath the temporary scaffold roof.
Engineering coordination
Structural Engineering
We prepared the structural drawings and calculations alongside the planning and Building Regulation work for Wrottesley Road.
The construction photographs show the structure at the junction between the retained house and the additions: steel beams and columns below the timber floors, new masonry beside the existing staircase, and roof framing around the retained chimney. The close-up of the bolted connection records one of those interfaces before the finishes cover it.
Our house structural engineer service formed part of the same appointment as the extension and loft design.
Technical compliance
Building Regulations
We also carried out the Building Regulation drawings for the extension and loft works.
The site views show where the new work meets the existing house: steel members below retained and new timber floors, new block walls beside the existing staircase, and the roof framing around the retained chimney. These are the parts of the project that will be covered by the finished ceilings, walls and roof coverings.
The front visualisation shows the intended external appearance. The remaining gallery images show work in progress.
Consent and delivery
Project Outcome
Brent Council granted planning permission for the side and rear extensions, hip-to-gable roof alteration, rear dormer and two front rooflights on 3 July 2026, under application 26/0882, subject to the conditions in the decision notice.
The officer accepted the combined extensions and their relationship with neighbouring properties. No consultation comments were received.
Construction is ongoing. The portfolio will be updated with photographs of the finished house.
