Outbuilding approval rate in Harrow

Harrow approved 79.1% of outbuilding applications, based on 974 decisions analysed.

Last updated: March 2026

79.1%

outbuilding approval rate

974

Outbuilding decisions

770

Approved

204

Refused

80.6%

Harrow overall

Outbuilding applications are approved at roughly the same rate as the Harrow average (80.6%).

How outbuilding compares in Harrow

Outbuilding (974 decided)

79.1%

Harrow all applications (12,600 decided)

80.6%

Planning a outbuilding in Harrow?

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Less than one set of revised drawings.

Other project types in Harrow

Rear Extension (4,812 decided)

78.2%

Garage / Parking (3,138 decided)

81.8%

Dormer (2,458 decided)

77.3%

Side Extension (2,430 decided)

74.7%

Front Extension (1,029 decided)

77.1%

Flat Conversion (829 decided)

92.2%

Extension (General) (684 decided)

81.4%

Change of Use (Residential) (642 decided)

83.8%

Conservatory (317 decided)

81.4%

Basement (307 decided)

85.0%

Wraparound Extension (223 decided)

82.5%

HMO (155 decided)

76.8%

New Build (139 decided)

79.1%

Loft Conversion (88 decided)

80.7%

Annex (54 decided)

42.6%

Hip-to-Gable Conversion (20 decided)

75.0%

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