House extensions in Hertsmere

Hertsmere received 749 householder applications in the last 12 months - about 14 a week. Rear extensions and dormers are the most common. Of the 562 decided so far, 485 were approved. If you're planning your own, the applications below show what people nearby applied for and how the council decided.

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Showing 50 of 192 applications
23 Oct 2026 Awaiting decision 26/1481/FUL

Battle Axes Inn Butterfly Lane Elstree Borehamwood Hertfordshire WD6 3AD

Construction of single-storey and two-storey extensions, proposed elevational changes and associated landscaping, including the extension of the car p...

Full Planning Permission Hertsmere
23 Oct 2026 Awaiting decision 26/1358/FUL

Flat 1 Wentworth The Avenue Bushey Hertfordshire WD23 2LL

Single storey rear extension.

Full Planning Permission Hertsmere
22 Oct 2026 Awaiting decision 26/1480/HSE

130 Mill Way Bushey Hertfordshire WD23 2AQ

Construction of single storey rear extension, front porch, rear extension to garage and outbuilding to rear garden; conversion of loft to habitable sp...

Householder Application Hertsmere
21 Oct 2026 Awaiting decision 26/1503/FUL

138 Darkes Lane Potters Bar Hertfordshire EN6 1AF

Single storey rear extension, alterations to the shopfront, relocation of the external rear steel staircase and installation of a commercial kitchen e...

Full Planning Permission Hertsmere
21 Oct 2026 Awaiting decision 26/1476/HSE

30 Farm Way Bushey Hertfordshire WD23 3SS

Construction of two storey side extension with associated roof works, single storey rear extension, conversion of loft to habitable space to include 3...

Householder Application Hertsmere
20 Oct 2026 Awaiting decision 26/1524/HSE

8 New Road Shenley Radlett Hertfordshire WD7 9EA

Erection of detached outbuilding in the garden.

Householder Application Hertsmere
20 Oct 2026 Awaiting decision 26/1523/HSE

36 Elm Walk Radlett Hertfordshire WD7 8DP

First floor front extension and conversion of loft to habitable space with hip-to-gable roof alterations to include rear dormer and insertion of 2x fr...

Householder Application Hertsmere
20 Oct 2026 Awaiting decision 26/1518/HSE

Lakeview 5 Lands End Elstree Borehamwood Hertfordshire WD6 3DL

Conversion of garage to habitable space including removal of garage door and replacement window. Replacement roof to include 6x roof lights and decora...

Householder Application Hertsmere
20 Oct 2026 Awaiting decision 26/1516/CLP

83 Dugdale Hill Lane Potters Bar Hertfordshire EN6 2DR

Conversion of loft to habitable space with side and rear dormer; single storey rear extension. Certificate of Lawful Development (Proposed).

Certificate Proposed Lawful Use/Dev Hertsmere
20 Oct 2026 Awaiting decision 26/1513/HSE

83 Dugdale Hill Lane Potters Bar Hertfordshire EN6 2DR

Single-storey rear extension to include connection to the existing detached garage and conversion to habitable space.

Householder Application Hertsmere
20 Oct 2026 Awaiting decision 26/1512/PD42

83 Dugdale Hill Lane Potters Bar Hertfordshire EN6 2DR

Demolition of existing conservatory to facilitate construction of single storey rear extension Depth: 8.00m, Height: 2.70m, Eaves: 2.70m.

PD- Prior Approval 42 day (Hsehold ext) Hertsmere
20 Oct 2026 Awaiting decision 26/1497/FUL

46 London Road Shenley Radlett Hertfordshire WD7 9DY

Demolition of existing garage and subdivision to facilitate construction of two storey detached dwelling, front boundary works to include re-positioni...

Full Planning Permission Hertsmere
20 Oct 2026 Awaiting decision 26/1496/HSE

54 Mount Grace Road Potters Bar Hertfordshire EN6 1RB

Construction of part first floor, part two storey front extension, part single, part two storey rear extension, and single storey side extension; alte...

Householder Application Hertsmere
19 Oct 2026 Awaiting decision 26/1511/HSE

1A Fairacres Close Potters Bar Hertfordshire EN6 2LT

Construction of single storey rear extension, front porch extension and conversion of loft to habitable space to include rear dormer and 1x front roof...

Householder Application Hertsmere
19 Oct 2026 Awaiting decision 26/1505/HSE

8 Williams Way Radlett Hertfordshire WD7 7EZ

The erection of a front boundary wall, piers and railings with an electrically operated setback inward-opening vehicular gate, including the reduction...

Householder Application Hertsmere
19 Oct 2026 Awaiting decision 26/1486/HSE

20 Rosebery Road Bushey Hertfordshire WD23 1DA

Two storey side extension, first floor rear extension and alterations to fenestration.

Householder Application Hertsmere
19 Oct 2026 Awaiting decision 26/1510/PD42

10 Barr Road Potters Bar Hertfordshire EN6 5PG

Single storey rear extension. Depth: 4m, Height: 2.95m, Eaves: 2.95m.

PD- Prior Approval 42 day (Hsehold ext) Hertsmere
19 Oct 2026 Awaiting decision 26/1507/CLP

30 Ladbrooke Drive Potters Bar Hertfordshire EN6 1QR

Single storey rear extension and conversion of loft to habitable space including hip to gable roof alterations, rear dormer, and 4x roof lights. Certi...

Certificate Proposed Lawful Use/Dev Hertsmere
19 Oct 2026 Awaiting decision 26/1502/HSE

Pheasants Retreat 10 New Road Letchmore Heath Watford Hertfordshire WD25 8ED

Erection of single storey attached garage and relocation of existing heat pump.

Householder Application Hertsmere
19 Oct 2026 Awaiting decision 26/1500/HSE

10 Oakridge Avenue Radlett Hertfordshire WD7 8EP

Demolition of existing rear conservatory and erection of part single part two storey rear extension with alterations to fenestration.

Householder Application Hertsmere
19 Oct 2026 Awaiting decision 26/1504/FUL

100 London Road Shenley Radlett Hertfordshire WD7 9DX

Single-storey front extension.

Full Planning Permission Hertsmere
19 Oct 2026 Awaiting decision 26/1474/FUL

3 - 5 Beech Drive Borehamwood Hertfordshire

Conversion of loft to habitable space to Nos. 3 and 5 Beech Drive, including raising the ridge height, four rear dormers and 8x front rooflights.

Full Planning Permission Hertsmere
16 Oct 2026 Awaiting decision 26/1493/HSE

5 Trafford Close Shenley Radlett Hertfordshire WD7 9HU

Construction of single storey outbuilding.

Householder Application Hertsmere
16 Oct 2026 Awaiting decision 26/1494/CLP

32 Billy Lows Lane Potters Bar Hertfordshire EN6 1XN

Demolition of existing garage and temporary shed to facilitate construction of single storey side extension, conversion of loft to habitable space to ...

Certificate Proposed Lawful Use/Dev Hertsmere
15 Oct 2026 Awaiting decision 26/1489/CLP

6 Minorca Close Bentley Heath Barnet Hertfordshire EN5 4FA

Erection of detached outbuilding in the rear garden for uses ancillary to the main dwelling. Certificate of Lawful Development (Proposed).

Certificate Proposed Lawful Use/Dev Hertsmere
15 Oct 2026 Awaiting decision 26/1488/PD42

32 Billy Lows Lane Potters Bar Hertfordshire EN6 1XN

Single storey rear extension. Depth: 6m, Height: 3.1m, Eaves: 2.75m.

PD- Prior Approval 42 day (Hsehold ext) Hertsmere
14 Oct 2026 Awaiting decision 26/1485/HSE

12 The Avenue Radlett Hertfordshire WD7 7DJ

Erection of boundary railings and wall with gates to existing carriage drive.

Householder Application Hertsmere
14 Oct 2026 Awaiting decision 26/1483/HSE

16 Nightingale Road Bushey Hertfordshire WD23 3NJ

Erection of a single-storey rear extension, together with replacement of existing rear double doors with glazed folding doors and associated internal ...

Householder Application Hertsmere
13 Oct 2026 Awaiting decision 26/1477/CLP

46 Kemp Place Bushey Hertfordshire WD23 1DW

Construction of front porch extension and single storey rear extension Certificate of Lawful Development (Proposed).

Certificate Proposed Lawful Use/Dev Hertsmere
13 Oct 2026 Awaiting decision 26/1430/CLP

67 Willow Way Potters Bar Hertfordshire EN6 2PR

Change of use from class C3 to C4 HMO (6 bed 6 person) and conversion of garage to habitable space Certificate of Lawful Development (Proposed).

Certificate Proposed Lawful Use/Dev Hertsmere
12 Oct 2026 Awaiting decision 26/1470/HSE

31 Whaley Road Potters Bar Hertfordshire EN6 2RA

Construction of single storey rear extension.

Householder Application Hertsmere
12 Oct 2026 Awaiting decision 26/1464/HSE

32 Laurel Fields Potters Bar Hertfordshire EN6 2BB

Single storey rear and side extensions to include conversion of existing garage to habitable space, replacement garage and bin store, and alterations ...

Householder Application Hertsmere
12 Oct 2026 Awaiting decision 26/1463/HSE

14 Tilehouse Close Borehamwood Hertfordshire WD6 4AS

Construction of front porch extension and conversion of loft to habitable space, with rear dormer and Juliette balcony.

Householder Application Hertsmere
12 Oct 2026 Awaiting decision 26/1462/PD42

61 Gills Hill Lane Radlett Hertfordshire WD7 8DG

Demolition of existing rear conservatory and construction of single storey rear extension. Depth: 4.00m, Height: 2.86m, Eaves: 2.62m.

PD- Prior Approval 42 day (Hsehold ext) Hertsmere
12 Oct 2026 Awaiting decision 26/1461/HSE

6 Frowyke Crescent South Mimms Potters Bar Hertfordshire EN6 3PQ

Conversion of loft to habitable space including rear dormer, 1x roof light, and 1x side window. Infill side extension and erection of front porch.

Householder Application Hertsmere
12 Oct 2026 Awaiting decision 26/1384/FUL

Units 8 And 9 Stirling Industrial Centre Stirling Way Borehamwood Hertfordshire

Joint planning application for top-floor extensions to Units 8 and 9, Stirling Industrial Centre, to enlarge the existing second-floor/mezzanine offic...

Full Planning Permission Hertsmere
9 Oct 2026 Awaiting decision 26/1457/CLP

15 Allandale Crescent Potters Bar Hertfordshire EN6 2JY

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

Certificate Proposed Lawful Use/Dev Hertsmere
9 Oct 2026 Awaiting decision 26/1400/LBC

Fold Farm Galley Lane Barnet Hertfordshire EN5 4RA

Repair of 5x existing windows and replacement of 11x existing windows.

Listed Building Consent Hertsmere
8 Oct 2026 Awaiting decision 26/1450/PD42

109 Elstree Road Bushey Heath Bushey Hertfordshire WD23 4EG

Demolition of existing conservatory to facilitate construction of single storey rear extensions Depth: 8.00m, Height: 2.93m, Eaves: 2.50m.

PD- Prior Approval 42 day (Hsehold ext) Hertsmere
8 Oct 2026 Awaiting decision 26/1449/HSE

43 Ladbrooke Drive Potters Bar Hertfordshire EN6 1QR

Conversion of garage to utility room including alterations to fenestration, installation of raised roof, and connection to the previously approved rea...

Householder Application Hertsmere
7 Oct 2026 Awaiting decision 26/1445/HSE

313 Mutton Lane Potters Bar Hertfordshire EN6 2AY

Single-storey rear extension to include integration of existing detached outbuilding and demolition of existing conservatory, conversion of loft to ha...

Householder Application Hertsmere
7 Oct 2026 Awaiting decision 26/1443/PD42

313 Mutton Lane Potters Bar Hertfordshire EN6 2AY

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

PD- Prior Approval 42 day (Hsehold ext) Hertsmere
7 Oct 2026 Awaiting decision 26/1425/FUL

22 - 24 Cockle Way Shenley Hertfordshire

Alterations to fenestrations to include replacement of existing double-glazed UPVC casement windows with new double-glazed UPVC windows and replacemen...

Full Planning Permission Hertsmere
7 Oct 2026 Awaiting decision 26/1440/FUL

High Point Kemprow Aldenham Watford Hertfordshire WD25 8BP

Demolition of existing garage/workshop and erection of a two-storey dwelling with habitable space at loft level. Erection of a triple-bay garage/carpo...

Full Planning Permission Hertsmere
7 Oct 2026 Awaiting decision 26/1408/CLP

29 Danziger Way Borehamwood Hertfordshire WD6 5DB

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
6 Oct 2026 Awaiting decision 26/1432/HSE

149 Dugdale Hill Lane Potters Bar Hertfordshire EN6 2DF

Demolition of existing detached garage to facilitate construction of part single, part two storey side and rear extension with associated roof alterat...

Householder Application Hertsmere
6 Oct 2026 Awaiting decision 26/1431/HSE

2 Grove Cottages Hogg Lane Elstree Borehamwood Hertfordshire WD6 3AL

Demolition of existing outbuilding to facilitate construction of part single part two storey rear extension and installation of solar panels.

Householder Application Hertsmere
6 Oct 2026 Awaiting decision 26/1416/HSE

105 Baker Street Potters Bar Hertfordshire EN6 2ET

Part single, part two storey side and rear extensions including conversion of garage to habitable space and alterations to fenestration. Conversion of...

Householder Application Hertsmere
5 Oct 2026 Awaiting decision 26/1427/PD42

40 Stevenage Crescent Borehamwood Hertfordshire WD6 4NR

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

PD- Prior Approval 42 day (Hsehold ext) Hertsmere
5 Oct 2026 Awaiting decision 26/1376/CLP

5 Golf Close Bushey Hertfordshire WD23 2DF

Conversion of loft to habitable room with associated roof alterations to include rear dormer and insertion of 2x front rooflights. Certificate of Lawf...

Certificate Proposed Lawful Use/Dev Hertsmere
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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, whether taller, larger or 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 those drawing a lot of comments, 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.