Hip to Gable Loft Conversion

Local Council: London Borough of Lambeth

Appeal Result: Allowed (Permission Granted)

Description: Erection of a rear dormer loft extension, plus hip-to-gable roof extension, with new rooflights to the front elevation.

Refusal Stated:

1) The proposed dormer and hip to gable roof extension, by reason of its scale, bulk and poor design would fail to be subordinate to the existing roof, and would fail to respect the architecture and character of the host dwelling. As such the extension would have a detrimental impact on the character and appearance of the host property and the group of terraced properties of which it forms a part. The proposal is therefore contrary to Policies Q5 and Q11 of the Lambeth Local Plan (2021) and the Council's adopted supplementary planning guidance on building alterations and extensions (2015).

2) The proposed front rooflights by reason of their scale and design would introduce an incongruous form of development which would harm the character and appearance of the host building to the detriment of the wider surrounding area and the uniformity of the roofscape of the wider terrace. The proposal would be contrary to Policies Q5, and Q11 of the Lambeth Local Plan (2021) and the Building Alterations and Extensions SPD (2015).

Background: This case concerned a modest two-storey end-of-terrace dwelling within a small cul-de-sac of similar homes, set noticeably lower than the adjoining terrace because of natural ground level changes. The proposal sought to replace the hipped roof with a gable and construct a full-width rear dormer to create additional habitable accommodation. At the time, the adjoining property had already secured permission through a Lawful Development Certificate to build an almost identical dormer. The Council, however, assessed the application in isolation and refused permission, claiming the combined result would be overly dominant and harmful to the rhythm and uniformity of the group.

At appeal, LSE demonstrated that the Council’s interpretation of harm was unduly rigid and failed to reflect the true character of the cul-de-sac. The Inspector accepted that the neighbouring property’s dormer—already under construction—was a material consideration of significant weight. It was shown that when viewed together, the two extensions would in fact restore balance and coherence to the terrace, achieving a unified composition rather than a discordant appearance.

The Inspector also noted that the development site sits well back from public viewpoints and that the rear roof is largely obscured from the street. The minor variations in roof height across the wider area were found to be characteristic of the local topography, meaning the proposal would not appear incongruous. Regarding the rooflights, their size and alignment mirrored those being installed next door, thereby helping to maintain consistency within the group.

By providing a clear understanding of site context and the visual relationship between adjoining dwellings, LSE successfully established that the proposal would not harm the character or appearance of the area. The Inspector agreed, concluding that while the dormer was of notable scale, the specific site circumstances justified an approval. Planning permission was therefore granted, confirming that thoughtful contextual design can achieve harmony even where local policy might otherwise suggest restraint.