House extensions in Welwyn Hatfield

Welwyn Hatfield received 776 householder applications in the last 12 months - about 15 a week. Rear extensions and garage works are the most common. Of the 643 decided so far, 560 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 143 applications
19 Oct 2026 Under Consultation 6/2026/1852/EM

88 Uplands Welwyn Garden City AL8 7EQ

Erection of a single storey rear extension, re-tiling and installation of solar panels to the main roof, and installation of an air sourced heat pump ...

ESTATE MANAGEMENT Welwyn Hatfield
16 Oct 2026 Under Consultation 6/2026/1813/HOUSE

19 Sherrardspark Road Welwyn Garden City AL8 7JW

Erection of porch

HOUSEHOLDER APPLICATION Welwyn Hatfield
16 Oct 2026 Under Consultation 6/2026/1883/EM

511 Howlands Welwyn Garden City AL7 4HS

Replacing and altering an existing window to reduce its width and height

ESTATE MANAGEMENT Welwyn Hatfield
16 Oct 2026 Under Consultation 6/2026/1880/EM

465 Howlands Welwyn Garden City AL7 4HP

Erection of garden office with an external air-conditioning unit and one storage shed

ESTATE MANAGEMENT Welwyn Hatfield
15 Oct 2026 Under Consultation 6/2026/1850/HOUSE

19 High Ridge Cuffley Potters Bar EN6 4JH

Erection of two storey side extension, upper floor side and rear extensions and new front entrance. Installation of a box dormer on the side elevation...

HOUSEHOLDER APPLICATION Welwyn Hatfield
15 Oct 2026 Under Consultation 6/2026/1788/EM

15 Brockswood Lane Welwyn Garden City AL8 7BA

Single storey side and part two storey rear extension

ESTATE MANAGEMENT Welwyn Hatfield
13 Oct 2026 Under Consultation 6/2026/1812/HOUSE

19 Sherrardspark Road Welwyn Garden City AL8 7JW

Erection of single storey rear infill extension with internal alterations

HOUSEHOLDER APPLICATION Welwyn Hatfield
13 Oct 2026 Under Consultation 6/2026/1746/EM

183 Peartree Lane Welwyn Garden City AL7 3XL

Insertion of a roof light to existing rear extension

ESTATE MANAGEMENT Welwyn Hatfield
9 Oct 2026 Under Consultation 6/2026/1824/HOUSE

110 Guessens Road Welwyn Garden City AL8 6RS

Erection of first-floor side extension

HOUSEHOLDER APPLICATION Welwyn Hatfield
9 Oct 2026 Under Consultation 6/2026/1821/HOUSE

32 Hertford Road Digswell Welwyn AL6 0DB

Erection of a part single storey and part two storey rear extension, garage conversion with replacement roof, installation of new front door and side ...

HOUSEHOLDER APPLICATION Welwyn Hatfield
8 Oct 2026 Under Consultation 6/2026/1799/EM

19 Sherrardspark Road, Welwyn Garden City, AL8 7JW

Erection of porch

ESTATE MANAGEMENT Welwyn Hatfield
8 Oct 2026 Under Consultation 6/2026/1798/EM

19 Sherrardspark Road Welwyn Garden City AL8 7JW

Single Storey Rear infill extension with internal alterations

ESTATE MANAGEMENT Welwyn Hatfield
8 Oct 2026 Under Consultation 6/2026/1778/EM

13 Fordwich Road Welwyn Garden City AL8 6EX

Chimney removal following stage 3 survey

ESTATE MANAGEMENT Welwyn Hatfield
8 Oct 2026 Under Consideration 6/2026/1793/LAWP

343 St Albans Road West Hatfield AL10 9RN

Certificate of lawfulness for proposed erection of outbuilding in the rear garden of the dwellinghouse

LAWFUL DEVELOPMENT - PROPOSED Welwyn Hatfield
7 Oct 2026 Under Consultation 6/2026/1757/FULL

Links Academy Hatfield Travellers Lane Hatfield AL10 8TJ

Erection of a single storey timber-framed outdoor room comprising a workshop/store, kitchen and covered communal area with fire pit

FULL PERMISSION Welwyn Hatfield
7 Oct 2026 Under Consultation 6/2026/1784/FULL

Colonial House 87 Great North Road AL9 5DA

Replacement bin store

FULL PERMISSION Welwyn Hatfield
7 Oct 2026 Under Consultation 6/2026/1791/EM

1 Brockett Close Welwyn Garden City AL8 7BN

Erection of a rear conservatory, chimney, rooflights and associated alterations; patio, retaining wall, steps and proposed tree removal

ESTATE MANAGEMENT Welwyn Hatfield
7 Oct 2026 Under Consultation 6/2026/1642/HOUSE

55 Dragon Road Hatfield AL10 9LY

Conversion of existing attached garage to a habitable room involving removal of the existing garage door, infilling with matching brickwork, installat...

HOUSEHOLDER APPLICATION Welwyn Hatfield
2 Oct 2026 Under Consultation 6/2026/1753/FULL

Howard House Welwyn Garden City AL8 6PA

External alterations and refurbishment of Howard House (upper residential flats and communal areas) including alterations to existing openings, replac...

FULL PERMISSION Welwyn Hatfield
2 Oct 2026 Under Consultation 6/2026/1736/EM

505 Howlands Welwyn Garden City AL7 4HS

Erection of a single storey front porch, with a flat roof. External walls, fascia, rainwater goods and finishes to match the existing dwelling. New co...

ESTATE MANAGEMENT Welwyn Hatfield
2 Oct 2026 Under Consultation 6/2026/1751/FULL

Unit A Bridgefields Welwyn Garden City AL7 1RX

Extend the Existing South East Elevation (resubmission of 6/2021/3317/FULL)

FULL PERMISSION Welwyn Hatfield
2 Oct 2026 Under Consultation 6/2026/1748/HOUSE

18 Bell Lane Brookmans Park AL9 7AY

Alterations and raising the ridge height to create a crown roof with front and rear dormer windows

HOUSEHOLDER APPLICATION Welwyn Hatfield
2 Oct 2026 Under Consultation 6/2026/1743/HOUSE

124 Parkway Welwyn Garden City AL8 6HN

Portico to front and side entrances, formation of two front dormer windows to existing roof space, new/repositioned rooflights on main roof and new/re...

HOUSEHOLDER APPLICATION Welwyn Hatfield
1 Oct 2026 Under Consultation 6/2026/1731/HOUSE

Lakeside Manor West End Lane Essendon Hatfield AL9 6AZ

Erection of a basement extension, fenestration alteration and wall and roof replacement

HOUSEHOLDER APPLICATION Welwyn Hatfield
1 Oct 2026 Under Consultation 6/2026/1678/HOUSE

Sunnyside Essendon Hill Essendon Hatfield AL9 6AJ

Installation of front dormer and insertion of bi folding doors to rear

HOUSEHOLDER APPLICATION Welwyn Hatfield
1 Oct 2026 Under Consultation 6/2026/1702/EM

35 Fordwich Road, Welwyn Garden City, AL8 6EY

Installation of new parapet wall to front elevation

ESTATE MANAGEMENT Welwyn Hatfield
1 Oct 2026 Under Consultation 6/2026/1061/EM

100 Cole Green Lane Welwyn Garden City AL7 3JD

Single-storey rear extension following demolition of the existing brick-built store.

ESTATE MANAGEMENT Welwyn Hatfield
1 Oct 2026 Under Consultation 6/2026/1726/PN8

52 Crookhams Welwyn Garden City AL7 1PF

Prior approval for a rear extension measuring 6m in depth, 2.5m to the eaves and the maximum height of 3m

Class A – enlargement, improvement or other alteration of a dwellinghouse - PRIOR APPROVAL Welwyn Hatfield
30 Sept 2026 Under Consultation 6/2026/1691/HOUSE

35 Fordwich Road Welwyn Garden City AL8 6EY

Installation of new parapet wall to front elevation and raising of part of existing flat roof.

HOUSEHOLDER APPLICATION Welwyn Hatfield
30 Sept 2026 Under Consideration 6/2026/1730/EM

6 Melbourne Court Welwyn Garden City AL8 6LL

Alterations to front and side elevations of the house and adding an EV charger to front elevation

ESTATE MANAGEMENT Welwyn Hatfield
29 Sept 2026 Under Consultation 6/2026/1647/HOUSE

19 Walker Grove Hatfield AL10 9PL

Erection of a single storey rear extension with balcony and the installation of glass balustrade, and proposed air conditioning unit, following the de...

HOUSEHOLDER APPLICATION Welwyn Hatfield
29 Sept 2026 Under Consultation 6/2026/1709/HOUSE

15 Thrush Lane Cuffley Potters Bar EN6 4JU

Erection of a single storey side/rear extension, following the demolition of existing rear conservatory

HOUSEHOLDER APPLICATION Welwyn Hatfield
28 Sept 2026 Under Consultation 6/2026/1705/EM

74 Newfields, Welwyn Garden City, AL8 6YT

Erection of garden room with attached shed

ESTATE MANAGEMENT Welwyn Hatfield
28 Sept 2026 Under Consultation 6/2026/1700/HOUSE

12 Pine Crest Welwyn AL6 0EQ

Erection of a single storey rear extension and additional floor to existing bungalow following removal of existing conservatory

HOUSEHOLDER APPLICATION Welwyn Hatfield
25 Sept 2026 Under Consultation 6/2026/1690/HOUSE

113 The Ridgeway Northaw EN6 4BG

Erection of ground floor front extension, proposed roof extension including side box dormer, front dormer window, installation of rooflights, demoliti...

HOUSEHOLDER APPLICATION Welwyn Hatfield
25 Sept 2026 Under Consideration 6/2026/1692/LAWP

78 Carve Ley Welwyn Garden City AL7 3HH

Certificate of lawfulness for the erection of a single storey ground floor extension

LAWFUL DEVELOPMENT - PROPOSED Welwyn Hatfield
25 Sept 2026 Under Consideration 6/2026/1653/EM

10 Handside Green Welwyn Garden City AL8 6SQ

Erection of a shed at read garden, replace rear garden gate and fencing and removing an internal Leylandii hedge

ESTATE MANAGEMENT Welwyn Hatfield
25 Sept 2026 Under Consideration 6/2026/1686/PN8

65 Maple Grove Welwyn Garden City AL7 1NN

Prior approval for the erection of a single storey rear extension measuring 6m in depth, 3m in height and 2.75m to the eaves

Class A – enlargement, improvement or other alteration of a dwellinghouse - PRIOR APPROVAL Welwyn Hatfield
24 Sept 2026 Under Consultation 6/2026/1669/EM

82 Attimore Road Welwyn Garden City AL8 6LP

New garden room to replace shed

ESTATE MANAGEMENT Welwyn Hatfield
24 Sept 2026 Under Consideration 6/2026/1688/EM

124 Parkway Welwyn Garden City AL8 6HN

Proposed portico to front and side entrances, new dormer windows to existing roof space, new/repositioned rooflights on main roof and new/repositioned...

ESTATE MANAGEMENT Welwyn Hatfield
24 Sept 2026 Under Consultation 6/2026/1649/FULL

17A The Broadway Hatfield AL9 5HZ

Erection of canopy

FULL PERMISSION Welwyn Hatfield
24 Sept 2026 Under Consultation 6/2026/1542/HOUSE

3 Scholars Mews Welwyn Garden City AL8 7JQ

Erection of freestanding aluminium garden pergola

HOUSEHOLDER APPLICATION Welwyn Hatfield
22 Sept 2026 Under Consultation 6/2026/1596/HOUSE

39 Station Road Welham Green Hatfield AL9 7PF

Erection of first floor side extension and timber cladding and rendering to existing front elevation

HOUSEHOLDER APPLICATION Welwyn Hatfield
22 Sept 2026 Under Consideration 6/2026/1675/HOUSE

20 Moffats Lane Brookmans Park AL9 7RU

Erection of garden room to rear elevation

HOUSEHOLDER APPLICATION Welwyn Hatfield
22 Sept 2026 Under Consideration 6/2026/1631/EM

22 Digswell Road Welwyn Garden City AL8 7PA

Installation of an air conditioning/heat pump unit and alterations to side elevation window

ESTATE MANAGEMENT Welwyn Hatfield
21 Sept 2026 Under Consultation 6/2026/1650/EM

61 Moorlands, Welwyn Garden City, AL7 4QJ

Erection of garden room

ESTATE MANAGEMENT Welwyn Hatfield
21 Sept 2026 Under Consideration 6/2026/1645/HOUSE

18 Great North Road Welwyn AL6 0PS

Erection of front porch and car port

HOUSEHOLDER APPLICATION Welwyn Hatfield
21 Sept 2026 Under Consultation 6/2026/1636/HOUSE

22 Digswell Road Welwyn Garden City AL8 7PA

Installation of an air conditioning/heat pump unit & alterations to side elevation window

HOUSEHOLDER APPLICATION Welwyn Hatfield
18 Sept 2026 Under Consideration 6/2026/1635/HOUSE

5 Old French Horn Lane Hatfield AL10 8AH

Replace existing boundary fence with 1m brick wall and 1.5m piers and hedge

HOUSEHOLDER APPLICATION Welwyn Hatfield
18 Sept 2026 Under Consideration 6/2026/1634/HOUSE

11 Lords Wood Welwyn Garden City AL7 2HF

Proposed garage conversion, widening of driveway to include a new parking space and erection of a garden room

HOUSEHOLDER APPLICATION Welwyn Hatfield
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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 Welwyn Hatfield?
Yes. Click "Set up alerts" on this page and you'll get a daily or weekly email listing every new extensions application published by Welwyn Hatfield. You can also narrow the alert to a postcode, street, or drawn area.

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