Our client had built a timber-clad garden room measuring 4.5m × 5m with a maximum height of 2.6m in the rear north-west corner of a recently built detached house. However, Condition 9 on the original planning permission (ref. 73683/APP/2018/3473) explicitly removed all permitted development rights for outbuildings under the GPDO 2015. This meant the garden room required full planning permission regardless of its size or position.
A further complication arose because a protected tree (T1) had been removed contrary to an approved Tree Protection Plan imposed by condition 4 of a subsequent permission (ref. 73683/APP/2021/2624). The site is bounded by allotments to the south and west, another residential property to the north, and the street to the east. No specific planning designations apply to the site.
“Notwithstanding the provisions of the Town and Country Planning (General Permitted Development) (England) Order 2015… no garage(s), shed(s) or other outbuilding(s), nor extension or roof alteration to any dwellinghouse(s) shall be erected without the grant of further specific permission from the Local Planning Authority.”
We submitted a full retrospective householder planning application supported by a comprehensive Planning Statement. The statement addressed the site’s extensive planning history — six prior applications — and demonstrated compliance with the London Plan, Hillingdon Local Plan and NPPF policies on design, character and residential amenity. A replacement tree was proposed to mitigate the loss of T1.
The garden room totals 19.7sqm (4.5m × 5m) with a height of 2.6m at the front elevation and 2.5m at the rear, incorporating a 100mm roof fall for drainage. Materials comprise a rubber membrane roof, timber cladding to the external walls, and an anthracite aluminium bi-fold door and window to the front elevation. The structure is positioned in the north-west corner of the rear garden.
Approved by the London Borough of Hillingdon. The officer’s report acknowledged that the garden room was modest in scale, single storey, and finished in materials that complement the host dwelling. The retrospective permission secures the building’s lawful status and provides certainty for the client going forward.
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