House extensions in Hertsmere

Hertsmere received 341 householder applications in the last 12 months - about 7 a week. Rear extensions and loft conversions are the most common. Of the 189 decided so far, 148 were approved. If you're planning your own, the applications below show what people nearby applied for and how the council decided.

159 last 90 days
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32 last 30 days
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20 last 14 days

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Showing 50 of 159 applications
26/0940/LBC 9 Jul 2026 Awaiting decision

Flat 5 Wessex House Marlborough Drive Bushey Hertfordshire WD23 2RP

Replacement of existing double glazed units in ensuite bathroom (Application for Listed Building Consent).

Hertsmere 9 Jul 2026
26/0931/PD42 8 Jul 2026 Awaiting decision

43 Ladbrooke Drive Potters Bar Hertfordshire EN6 1QR

Single storey rear extension. Depth: 6.00m, Height: 4.00m, Eaves: 2.47m.

Hertsmere 8 Jul 2026
26/0933/DOC 8 Jul 2026 Awaiting decision

5 Warren Road Bushey Heath Bushey Hertfordshire WD23 1HU

Application for approval of details reserved by condition 3 (details of windows, doors, fascia and sills) of planning permission reference 25/0914/HSE...

Hertsmere 8 Jul 2026
26/0929/HSE 8 Jul 2026 Awaiting decision

8 Avenue Rise Bushey Hertfordshire WD23 3AS

Single storey side extension (following demolition of side garage); single storey rear extension and rear patio/terrace including alterations to land ...

Hertsmere 8 Jul 2026
26/0930/FUL 8 Jul 2026 Awaiting decision

6 Elstree Way Borehamwood Hertfordshire WD6 1RN

Alterations to fenestration including removal of window and replacement side access door. (Part retrospective)

Hertsmere 8 Jul 2026
26/0928/HSE 7 Jul 2026 Awaiting decision

5 Dellfield Close Radlett Hertfordshire WD7 8LS

Construction of two storey side and part single part two storey rear extension. Erection of detached double garage with ancillary utility space follow...

Hertsmere 7 Jul 2026
26/0919/PD42 6 Jul 2026 Awaiting decision

77 Manor Way Borehamwood Hertfordshire WD6 1QR

Single storey rear extension. Depth: 6.0m Height: 3.2m, Eaves: 2.4m.

PD- Prior Approval 42 day (Hsehold ext) Hertsmere 6 Jul 2026
26/0920/HSE 6 Jul 2026 Awaiting decision

60 Homefield Road Bushey Hertfordshire WD23 3FA

Construction of part single, part two storey side and rear extension.

Hertsmere 6 Jul 2026
26/0912/HSE 3 Jul 2026 Awaiting decision

34 Elmroyd Avenue Potters Bar Hertfordshire EN6 2EE

Conversion of loft to habitable space to include rear dormer.

Householder Application Hertsmere 3 Jul 2026
26/0921/HSE 3 Jul 2026 Awaiting decision

29 Kenilworth Drive Borehamwood Hertfordshire WD6 1QL

Installation of rear conservatory.

Householder Application Hertsmere 3 Jul 2026
26/0918/CLP 3 Jul 2026 Awaiting decision

123 Church Road Potters Bar Hertfordshire EN6 1EU

Conversion of loft to habitable space with rear dormer, insertion of 3x front rooflights, side window at loft level and removal of chimney stack. Cert...

Certificate Proposed Lawful Use/Dev Hertsmere 3 Jul 2026
26/0917/CLP 3 Jul 2026 Awaiting decision

123 Church Road Potters Bar Hertfordshire EN6 1EU

Conversion of loft to habitable space including rear dormer, 3x front roof lights, and side window. Certificate of lawful development (Proposed).

Certificate Proposed Lawful Use/Dev Hertsmere 3 Jul 2026
26/0913/HSE 3 Jul 2026 Awaiting decision

78 Mount Grace Road Potters Bar Hertfordshire EN6 1QZ

Construction of single storey rear extension and patio alterations (part-retrospective).

Hertsmere 3 Jul 2026
26/0909/CLP 1 Jul 2026 Awaiting decision

109 Elstree Road Bushey Heath Bushey Hertfordshire WD23 4EG

Single storey side extensions and conversion of loft to habitable space including hip to gable roof alterations and rear dormer. Certificate of lawful...

Certificate Proposed Lawful Use/Dev Hertsmere 1 Jul 2026
26/0910/HSE 1 Jul 2026 Awaiting decision

314 Shenley Road Borehamwood Hertfordshire WD6 1TT

Conversion of loft to habitable space including rear dormer and front roof light.

Householder Application Hertsmere 1 Jul 2026
26/0908/PD42 30 Jun 2026 Awaiting decision

45 Highview Gardens Potters Bar Hertfordshire EN6 5PN

Single storey rear extension. Depth: 6m, Height: 3m, Eaves: 3m.

PD- Prior Approval 42 day (Hsehold ext) Hertsmere 30 Jun 2026
26/0895/HSE 29 Jun 2026 Awaiting decision

39 Tempsford Avenue Borehamwood Hertfordshire WD6 2PD

Two storey side extension with associated roof works.

Householder Application Hertsmere 29 Jun 2026
26/0898/LBC 29 Jun 2026 Awaiting decision

The White Hart St Albans Road South Mimms Potters Bar Hertfordshire EN6 3PJ

Replacement of existing windows with bespoke timber windows (Application for Listed Building Consent).

Listed Building Consent Hertsmere 29 Jun 2026
26/0894/HSE 29 Jun 2026 Awaiting decision

Pathways The Pathway Radlett Hertfordshire WD7 8JB

Erection of a small elevated timber built play structure.

Householder Application Hertsmere 29 Jun 2026
26/0886/CLP 26 Jun 2026 Awaiting decision

84 Hartforde Road Borehamwood Hertfordshire WD6 5JT

Demolition of existing outbuilding to facilitate construction of single storey rear extension. Certificate of Lawful Development (Proposed).

Certificate Proposed Lawful Use/Dev Hertsmere 26 Jun 2026
26/0888/CLP 26 Jun 2026 Awaiting decision

22 Bullhead Road Borehamwood Hertfordshire WD6 1HS

Conversion of loft to habitable space including hip to gable roof alterations, rear dormer and 2x front roof lights. Certificate of lawful development...

Certificate Proposed Lawful Use/Dev Hertsmere 26 Jun 2026
26/0887/PD42 26 Jun 2026 Awaiting decision

22 Bullhead Road Borehamwood Hertfordshire WD6 1HS

Single storey rear extension. Depth: 6.00m, Height: 3.01m, Eaves: 2.91m.

PD- Prior Approval 42 day (Hsehold ext) Hertsmere 26 Jun 2026
26/0892/HSE 26 Jun 2026 Awaiting decision

22 Bullhead Road Borehamwood Hertfordshire WD6 1HS

Construction of two storey side and rear extension and single storey outbuilding.

Householder Application Hertsmere 26 Jun 2026
26/0872/CLP 24 Jun 2026 Awaiting decision

118 Theobald Street Borehamwood Hertfordshire WD6 4PA

Conversion of loft to habitable space with associated hip to gable roof alterations, to include rear dormer, insertion of 3x front rooflights and remo...

Certificate Proposed Lawful Use/Dev Hertsmere 24 Jun 2026
26/0867/PD42 23 Jun 2026 Awaiting decision

24 Southgate Road Potters Bar Hertfordshire EN6 5DZ

Single storey rear extension. Depth: 8.0m, Height: 3.0m, Eaves: 3.0m.

PD- Prior Approval 42 day (Hsehold ext) Hertsmere 23 Jun 2026
26/0866/FUL 23 Jun 2026 Awaiting decision

225 Darkes Lane Potters Bar Hertfordshire EN6 1BX

Construction of single storey rear extension to allow for subdivision of dwelling to create 3x flats, including provision of parking, EV chargers, cyc...

Full Planning Permission Hertsmere 23 Jun 2026
26/0865/CLP 23 Jun 2026 Awaiting decision

15 Thornbury Gardens Borehamwood Hertfordshire WD6 1RB

Erection of outbuilding in rear garden. Certificate of lawful development (Proposed).

Certificate Proposed Lawful Use/Dev Hertsmere 23 Jun 2026
26/0858/CLP 22 Jun 2026 Awaiting decision

25 Wright Close Bushey Hertfordshire WD23 2FH

Single storey rear extension. Certificate of lawful development (Proposed).

Certificate Proposed Lawful Use/Dev Hertsmere 22 Jun 2026
26/0861/CLP 22 Jun 2026 Awaiting decision

18 Kemprow Aldenham Watford Hertfordshire WD25 8BP

Construction of single storey outbuilding. Certificate of Lawful Development (Proposed).

Certificate Proposed Lawful Use/Dev Hertsmere 22 Jun 2026
26/0860/PD42 22 Jun 2026 Awaiting decision

26 Caishowe Road Borehamwood Hertfordshire WD6 5JA

Single storey rear extension Depth: 6.00m, Height: 4.00m, Eaves: 3.00m.

PD- Prior Approval 42 day (Hsehold ext) Hertsmere 22 Jun 2026
26/0850/HSE 19 Jun 2026 Awaiting decision

20 Mandeville Road Potters Bar Hertfordshire EN6 5LQ

Demolition of existing rear conservatory and detached garage, and construction of a single storey rear extension, and alterations to fenestration.

Householder Application Hertsmere 19 Jun 2026
26/0845/CLP 18 Jun 2026 Awaiting decision

24 Farm Way Bushey Hertfordshire WD23 3SS

Conversion of loft to habitable space to include rear dormer, 2x front rooflights and alterations to fenestration. Certificate of Lawful Development (...

Certificate Proposed Lawful Use/Dev Hertsmere 18 Jun 2026
26/0791/CLP 8 Jun 2026 Awaiting decision

56 Rushfield Potters Bar Hertfordshire EN6 3HJ

Conversion of loft to habitable space with rear dormer and Juliet balcony, and insertion of 3x front rooflights. Certificate of Lawful Development (Pr...

Certificate Proposed Lawful Use/Dev Hertsmere 8 Jun 2026
26/0778/HSE 5 Jun 2026 Awaiting decision

34 The Squirrels Bushey Hertfordshire WD23 4RT

Part single part two storey side extension and single storey rear extension.

Householder Application Hertsmere 5 Jun 2026
26/0780/HSE 5 Jun 2026 Awaiting decision

2 Sutton Path Borehamwood Hertfordshire WD6 1UH

Single storey side and rear extension following demolition of conservatory,

Householder Application Hertsmere 5 Jun 2026
26/0766/FUL 4 Jun 2026 Awaiting decision

10A The Walk Potters Bar Hertfordshire EN6 1QL

Construction of outbuilding to rear garden for use as gym and office.

Full Planning Permission Hertsmere 4 Jun 2026
26/0772/CLP 4 Jun 2026 Awaiting decision

57 Grantham Green Borehamwood Hertfordshire WD6 2JQ

Conversion of loft to habitable space including rear dormer and 3x front roof lights. Certificate of lawful development (Proposed).

Certificate Proposed Lawful Use/Dev Hertsmere 4 Jun 2026
26/0771/PD42 4 Jun 2026 Awaiting decision

26 Kimptons Mead Potters Bar Hertfordshire EN6 3HZ

Single storey rear extension. Depth: 4.5m, Height: 3.0m, Eaves: 3.0m.

PD- Prior Approval 42 day (Hsehold ext) Hertsmere 4 Jun 2026
26/0770/HSE 4 Jun 2026 Awaiting decision

36 Mulberry Gardens Shenley Radlett Hertfordshire WD7 9LB

Single storey rear extension.

Householder Application Hertsmere 4 Jun 2026
26/0775/PD42 4 Jun 2026 Awaiting decision

31 Whaley Road Potters Bar Hertfordshire EN6 2RA

2no. single storey rear extensions. Depth: 6m, Height: 3m, Eaves: 3m.

PD- Prior Approval 42 day (Hsehold ext) Hertsmere 4 Jun 2026
26/0777/HSE 4 Jun 2026 Awaiting decision

The Studio Hilfield Lane Aldenham Watford Hertfordshire WD25 8PF

Construction of single storey outbuilding.

Householder Application Hertsmere 4 Jun 2026
26/0774/HSE 4 Jun 2026 Awaiting decision

Grove House 21 Shenley Hill Radlett Hertfordshire WD7 7AT

Construction of single storey outbuilding.

Householder Application Hertsmere 4 Jun 2026
26/0776/PD42 4 Jun 2026 Awaiting decision

31 Whaley Road Potters Bar Hertfordshire EN6 2RA

Single storey rear extensions Depth: 6.00m, Height: 3.00m, Eaves: 3.00m.

PD- Prior Approval 42 day (Hsehold ext) Hertsmere 4 Jun 2026
26/0759/HSE 3 Jun 2026 Awaiting decision

10 Aldenham Grove Radlett Hertfordshire WD7 7BW

Part single, part two storey side extension with balcony, two pergolas, and alterations to the existing openings and patio.

Householder Application Hertsmere 3 Jun 2026
26/0755/HSE 3 Jun 2026 Awaiting decision

24 Ormesby Drive Potters Bar Hertfordshire EN6 3DZ

Erection of outbuilding following demolition of existing outbuilding.

Householder Application Hertsmere 3 Jun 2026
26/0764/FUL 3 Jun 2026 Awaiting decision

Canada Life Place Building Mutton Lane Potters Bar EN6 5BA

External alterations to facade and fenestration, removal of rooftop plant enclosure, and associated landscaping works.

Full Planning Permission Hertsmere 3 Jun 2026
26/0749/HSE 2 Jun 2026 Awaiting decision

12 Wilcox Close Borehamwood Hertfordshire WD6 5PY

Single storey front and side extension.

Householder Application Hertsmere 2 Jun 2026
26/0748/HSE 2 Jun 2026 Awaiting decision

2 The Cottages Great North Road Barnet Hertfordshire EN5 4RG

Demolition of existing detached garag; removal of existing side fence; construction of a replacement single storey side extension; installation of fro...

Householder Application Hertsmere 2 Jun 2026
26/0744/PD42 1 Jun 2026 Awaiting decision

19 Dove Lane Potters Bar Hertfordshire EN6 2SG

Single storey rear extension. Depth: 6m, Height: 3m, Eaves: 2.69m.

PD- Prior Approval 42 day (Hsehold ext) Hertsmere 1 Jun 2026
26/0747/HSE 1 Jun 2026 Awaiting decision

37 Hill Rise Potters Bar Hertfordshire EN6 2RX

Rear infill extension to include 2x roof lights.

Householder Application Hertsmere 1 Jun 2026
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Frequently asked questions

When do you need planning permission for a house extension?
Single-storey rear extensions up to 4m (detached) or 3m (semi-detached / terraced) are usually permitted development. Two-storey extensions, anything in a conservation area, or larger projects almost always need a planning application.
What's the difference between planning permission and permitted development?
Permitted development rights let you build certain things without applying for planning permission, subject to specified limits. Anything outside those limits — taller, larger, in a protected area — needs full planning permission.
How long does a householder application take?
The statutory target is 8 weeks from validation. Most simple householder extensions are decided within that window; complex or contested cases (especially with objections) can take longer.
Can I get email alerts for new extensions applications in Hertsmere?
Yes. Click "Set up alerts" on this page and you'll get a daily or weekly email listing every new extensions application published by Hertsmere. You can also narrow the alert to a postcode, street, or drawn area.

We check Hertsmere's planning portal daily. New extensions applications appear here within a day of being published.