Planning application
39 Cornwall Avenue London N3 1LG
Works: Extension Loft or dormer Windows or glazing
Still open. Anyone can comment while the consultation period runs, and comments go to the council rather than to us.
Proposal
Roof extension involving hip to gable, rear dormer window and 3no. front facing rooflights
As published by the council, reference 25/5142/192
Application record
- Reference
- 25/5142/192
- Type
- Proposed Lawful Development Certificate
- Status
- Pending Decision
- Received
- 22 Dec 2025
- Validated
- 22 Dec 2025
- Ward
- West Finchley
- Postcode
- N3 1LG
Timeline
Dates from the published record
-
22 Dec 2025
Received by Barnet
-
10 Aug 2026
Added to PlanIndex
-
Decision
Awaiting decision
Decision expected by 16 February 2026, 8 weeks from validation under the statutory target for most applications. Extensions of time are common and are agreed case by case.
Barnet took a median of 42 days over the applications it decided in the last year.
Who's behind it
Company information only, from the register and Companies House
Agent on file, a design practice
4 applications on PlanIndex · across 3 councils
Trade members see who it is, their full track record, and every application they have filed.
See who's behind itDocuments
Plans, drawings, consultee responses and the officer's report
7 documents on file for this application
A planning file usually holds the application form, drawings and site plans, consultee responses, the officer's report and the decision notice.
Trade members open them from here.
Open the documentsWhat happens while it is decided
The process from here
This application is with Barnet for determination. The council publicises it, consults neighbours and technical bodies where required, and weighs the responses against local and national planning policy.
The statutory target is eight weeks for most applications and thirteen for major development, though extensions of time are common. Comments carry most weight while the case is undecided, so check the council portal for the deadline if you want to respond.
About lawful development applications
How this application type works
A lawful development certificate is a legal determination, not a planning judgement. It asks the council to confirm either that existing use or works are lawful, often through the passage of time, or that a proposal would not need planning permission at all. The applicant must prove the facts; the merits of the scheme are not considered.
Nearby applications
Within 500 metres
-
39 Cornwall Avenue London N3 1LG
77% historically approved · decision due ~12 Nov
Single storey rear extension. Conversion of the existing garage into habitable room, insertion of window to replace the garage door
Awaiting decision Householder Extension Windows or glazing 9 docsSmall domestic -
37 Cornwall Avenue London N3 1LG
Conversion of the existing dwelling into 2no. self-contained flats including single storey rear extension with green roof and parapet, front porch infill, first floor rear terrace area with obscure glazing, roof extension involving rear dormer window and 4no. front facing rooflights
Refused Full applications New dwelling Extension +2 12 docsSmall domestic -
37 Cornwall Avenue London N3 1LG
Single storey rear extension following demolition of the existing sun room. Roof extension involving rear dormer windows and 4no. front facing rooflights
Granted Householder Extension Loft or dormer +2 13 docsSmall domestic -
39 Cornwall Avenue London N3 1LG
77% historically approved · decision due ~27 Oct
New front porch
Awaiting decision Householder ExtensionSmall domestic -
32 Cornwall Avenue London N3 1LG
79% historically approved · decision due ~1 Oct
Conversion of part of the 1st floor and 2nd floor to create 1no. self-contained residential dwelling (Use Class C3)
Awaiting decisionDomestic -
First Floor Flat 33 Grove Avenue London N3 1QS
Change of use of the upper floor flat (Class C3) to a 3 bed House in Multiple Occupation (HMO) (Class C4). Associated refuse/recycling and cycle storage (AMENDED DESCRIPTION)
Refused Full applications 15 docs
Other lawful development applications
In Barnet
-
26/1907/191 Decided
8 Golders Manor Drive London NW11 9HT
Use of the property as a self-contained residential unit at ground floor level and the first and second floors as a 4-bedroom, 4-person House in Multiple Occupation (Sui Generis) (AMENDED DESCRIPTION)
-
26/2059/192 Decided
Low Ridge Rowley Lane Barnet EN5 3HS
Erection of a rear outbuilding
-
26/2066/192 Decided
355 Hendon Way London NW4 3NB
Roof extension involving rear dormer window and 3no. front facing rooflights. Removal of chimney on rear elevation (AMENDED DESCRIPTION)
-
26/1663/192 Decided
152 Deans Lane Edgware HA8 9NT
Change of use from single family dwellinghouse (Class C3a) to supported living accommodation Class C3b)
-
26/2025/192 Decided
18 Hale Drive London NW7 3DU
Roof extension involving hip to gable, rear dormer window, 2no. front facing rooflights and new side gable window