17 Northumberland Avenue, Isleworth, TW7 5HZ

1. 15 Sep 2026

   Received by Hounslow

2. 20 Sep 2026

   Added to PlanIndex

3. Decision

   Awaiting decision

   Decision expected by 10 November 2026, 8 weeks from validation under the statutory target for most applications. Extensions of time are common and are agreed case by case.

   Hounslow took a median of 56 days over the applications it decided in the last year.

This application is with Hounslow for determination, against a statutory target of eight weeks. Over the last year Hounslow decided lawful development applications in a median of 55 days. More in our guide to how long planning decisions take.

A lawful development certificate is a legal determination that existing or proposed works do not need planning permission; the merits of the scheme are not considered. More in our guide to planning application types.

• 21 NORTHUMBERLAND AVENUE, ISLEWORTH, TW7 5HZ

  P/2023/0434 Submitted 10 Feb 2023 50 yards away

  Erection of a part single storey, part two storey side and rear wraparound extension alterations to front porch.

  Refused Householder Extension 12 docs
  Small domestic

• 32 Campion Road, Isleworth, TW7 5HS

  P/2025/2483 Submitted 12 Aug 2025 100 yards away

  Erection of two storey side and single storey rear extension and single storey extension and conversion of the garage into a habitable room to the house..

  Withdrawn Householder Extension 3 docs
  Small domestic

• 32 Campion Road, Isleworth, TW7 5HS

  P/2025/2795 Submitted 17 Sep 2025 100 yards away

  Erection of a single storey rear infill extension, erection of two storey side extension and a single storey side extension to the house.

  Granted Householder Extension 6 docs
  Small domestic

• 3 Downs View, Isleworth, TW7 5HF

  P/2024/3116 Submitted 17 Sep 2024 100 yards away

  Erection of a single storey rear wrap-around extension and conversion of the existing garage into a habitable space.

  Granted Householder Extension 26 docs
  Small domestic

• 23 Downs View, Isleworth, TW7 5HF

  P/2024/3516 Submitted 22 Oct 2024 100 yards away

  Certificate of lawfulness for a hip to gable conversion and erection of a rear roof extension with three front roof windows to the house

  Granted Lawful development Extension Loft or dormer +1 7 docs

• 23 Downs View, Isleworth, TW7 5HF

  P/2025/2500 Submitted 12 Aug 2025 100 yards away

  Erection of a single storey ground floor side extension and part rear infill extension to the house. Following the demolition of the garage.

  Withdrawn Householder Extension Demolition 6 docs
  Small domestic

• P/2026/2651 Awaiting decision

  3 Clayponds Avenue, Brentford, TW8 9QQ

  Certificate of lawfulness for the proposed erection of a rear roof extension with two roof windows to the front of the house.

  Received 17 Sep, published by the council 20 Sep 2026 Lawful development
• P/2026/2627 Awaiting decision

  23 Elmgate Avenue, Feltham, TW13 7BU

  Certificate of lawfulness for the proposed change of use from residential house Class C3a to a residential home for up to 3 young people aged between 7 and 18 Class C2

  Received 15 Sep, published by the council 20 Sep 2026 Lawful development
• P/2026/2606 Awaiting decision

  35 Jersey Road, Hounslow, TW3 4BQ

  Certificate of Lawfulness for the Existing Continued Use as a Five Bedroom House in Multiple Occupation (HMO).

  Received 14 Sep, published by the council 20 Sep 2026 Lawful development
• P/2026/2609 Awaiting decision

  47 Sutton Road, Hounslow, TW5 0PN

  Certificate of lawfulness for the proposed erection of a detached outbuilding in the rear garden.

  Received 14 Sep, published by the council 20 Sep 2026 Lawful development
• P/2026/2118 Granted

  54 Amhurst Gardens, Isleworth, TW7 6AJ

  Certificate of lawfulness for the proposed erection of a rear roof extension with front roof windows.

  Received 20 Jul, published by the council 26 Jul 2026 Lawful development