Outbuilding and garden room planning approval rate in Hillingdon
81% of 1,230 decided outbuilding and garden room applications in Hillingdon were approved.
Checked against 20.6 million UK planning applications on file across 420 planning authorities. Approval rates from 2,343,419 decisions we classified across 181 councils in England.
A similar project nearby can help you understand the council's decisions. Its outcome does not establish what will be acceptable at your address.
81%
Approval rate, all years, from 1,230 decided
1,230
decided outbuilding and garden room applications in Hillingdon: 996 approved, 234 refused
83%
Recent rate, decided since 2022, from 921 decided
How to read these rates
These are historical outcomes for the applications in our archive, not the chance of approval for your property. Compare the same project type and read the decided count alongside each percentage.
About the planning data
Rate = approved divided by approved plus refused, using the decisions in our classified archive. Rates are withheld as unknown where fewer than 8 records of that project type were decided. Withdrawn applications are excluded.
Recent means records dated 2022 or later. Records without a year are excluded from the recent rate but remain in the all-years figure. Historical coverage varies by council, and duplicate application references may remain in the archive.
Approval rates from 2,343,419 decisions we classified across 181 councils in England. The wider 20.6 million application catalogue is accessible through PlanIT; it is not the dataset used to calculate these percentages.
Read the full methodology and coverage notes.
Project types and outcomes are classified from council records. Check the original application and decision notice before relying on an individual example. A page rebuild does not mean every council record has just been refreshed.
Example outbuilding and garden room decisions in Hillingdon
These examples deliberately include approved and refused applications where available. They are not a representative sample or a list of the latest decisions. Look up each reference on the council's planning search to read the plans and decision notice.
| Reference | Year | Decision | Application |
|---|---|---|---|
| 10810/APP/2026/55 | 2026 | Approved | Erection of an outbuilding to rear garden to be used for a games, gym, workshop, sauna and indoor swimming pool (Application for a Certificate of Lawful Deve... 98 EVELYN AVENUE |
| 11257/APP/2025/2371 | 2026 | Refused | Erection of new detached dwellinghouse with associated landscaping, parking, cycle and bin storage, following the demolition of existing outbuilding. 23 COWLEY CRESCENT |
| 12035/APP/2025/2690 | 2026 | Refused | Erection of 4x side dormers, raising of ridge, front porch, an outbuilding and a side access gate to the rear garden. 28 PIELD HEATH AVENUE |
| 14304/APP/2026/23 | 2026 | Approved | Erection of outbuilding to rear garden for use as a gym and store, following the demolition of existing shed (Application for a Certificate of Lawful Develop... 29 VINE LANE |
| 14440/APP/2026/116 | 2026 | Refused | Alteration of outbuilding's partial flat roof into a gable end roof extending over the whole outbuilding 28 DAWLEY AVENUE |
| 14824/APP/2026/66 | 2026 | Approved | Non-material amendment to planning permission ref. 14824/APP/2024/543, dated 04-03-25 (Erection of an outbuilding and shed to rear garden following the demol... 50 TORCROSS ROAD |
About the planning data
Checked against 20.6 million UK planning applications on file across 420 planning authorities. Approval rates from 2,343,419 decisions we classified across 181 councils in England.
Other project types in Hillingdon
- Single-storey rear extension 83%, 7,240 decided
- Two-storey rear extension 66%, 2,756 decided
- Wraparound extension 79%, 844 decided
- Side extension 71%, 1,686 decided
- Loft conversion and dormer 74%, 585 decided
- Rooflight 89%, 2,768 decided
- Porch 75%, 374 decided
- Garage conversion 89%, 425 decided
- Basement 86%, 432 decided
- Window and door 86%, 496 decided