Outbuilding approval rate in Harrow

Harrow approved 78.8% of outbuilding applications, based on 1,794 decisions analysed.

Last updated: August 2026

78.8%

outbuilding approval rate

1,794

Outbuilding decisions

1,413

Approved

381

Refused

75.9%

Harrow overall

Outbuilding applications are approved more often than the Harrow average (75.9%), suggesting the council is relatively receptive to these projects.

How outbuilding compares in Harrow

Outbuilding (1,794 decided)

78.8%

Harrow all applications (22,151 decided)

75.9%

Planning a outbuilding in Harrow?

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Other project types in Harrow

Rear Extension (10,671 decided)

75.4%

Dormer (4,314 decided)

74.6%

Side Extension (4,286 decided)

73.7%

Garage / Parking (3,725 decided)

76.4%

Front Extension (1,922 decided)

77.3%

Extension (General) (923 decided)

76.7%

Change of Use (Residential) (761 decided)

62.5%

Conservatory (588 decided)

80.8%

HMO (304 decided)

55.6%

Wraparound Extension (290 decided)

75.9%

Flat Conversion (278 decided)

63.3%

Basement (268 decided)

69.8%

Loft Conversion (119 decided)

70.6%

Annex (78 decided)

43.6%

Hip-to-Gable Conversion (66 decided)

86.4%

New Build (63 decided)

77.8%

← All Harrow planning statistics

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