House extensions in Welwyn Hatfield

Welwyn Hatfield received 775 householder applications in the last 12 months - about 15 a week. Rear extensions and garage works are the most common. Of the 605 decided so far, 524 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 160 applications
7 Sept 2026 Under Consultation 6/2026/1343/MAJ

Welwyn Garden City Golf Club Mannicotts Welwyn Garden City AL8 7BP

Installation of new doors to rear elevation

MAJOR DEVELOPMENT Welwyn Hatfield
3 Sept 2026 Under Consultation 6/2026/1494/PN8

6 West View Hatfield AL10 0PJ

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

Class A – enlargement, improvement or other alteration of a dwellinghouse - PRIOR APPROVAL Welwyn Hatfield
1 Sept 2026 Under Consultation 6/2026/1526/HOUSE

32 Turpins Chase Welwyn AL6 0RR

Erection of a single storey side extension and a new garage on ground floor level, conversion of the existing garage and installation of an air source...

HOUSEHOLDER APPLICATION Welwyn Hatfield
28 Aug 2026 Under Consultation 6/2026/1518/HOUSE

48 Great Ganett Welwyn Garden City AL7 3DE

Erection of single storey rear extension

HOUSEHOLDER APPLICATION Welwyn Hatfield
28 Aug 2026 Under Consultation 6/2026/1487/EM

5 Ashley Close Welwyn Garden City AL8 7LH

Proposed addition of a 3104 x 5474 mm pent roofed wooden shed to rear garden

ESTATE MANAGEMENT Welwyn Hatfield
28 Aug 2026 Under Consideration 6/2026/1240/LAWP

45 Briars Wood Hatfield AL10 8DH

Certificate of lawfulness for driveway and dropped kerb

LAWFUL DEVELOPMENT - PROPOSED Welwyn Hatfield
27 Aug 2026 Pending 6/2026/1506/LAWP

Gosmore Brocket Road Welwyn Garden City AL8 7TT

Erection of single storey side extensions x 2 and two storey rear extension

LAWFUL DEVELOPMENT - PROPOSED Welwyn Hatfield
27 Aug 2026 Pending 6/2026/1384/FULL

41 Howardsgate Welwyn Garden City AL8 6AP

Change of use from Class E to Sui Generis, installation of kitchen extraction canopy and air supply system on the rear flat roof and 3x cowl lights an...

FULL PERMISSION Welwyn Hatfield
27 Aug 2026 Pending 6/2026/1303/HOUSE

9 Youngs Rise Welwyn Garden City AL8 6RT

Erection of a single storey side extension, part single and part two storey rear extension, with alterations to openings on side elevations and new pa...

HOUSEHOLDER APPLICATION Welwyn Hatfield
26 Aug 2026 Under Consultation 6/2026/1502/HOUSE

143 The Ryde Hatfield AL9 5DP

Erection of single storey rear extension with raising of roof to existing extension, and alterations to openings to rear and side elevations

HOUSEHOLDER APPLICATION Welwyn Hatfield
26 Aug 2026 Under Consultation 6/2026/1476/HOUSE

9 Barleycroft Green Welwyn Garden City AL8 6JY

Replacement of existing wooden garage with wooden shed

HOUSEHOLDER APPLICATION Welwyn Hatfield
26 Aug 2026 Under Consultation 6/2026/1084/FULL

1 Heay Fields Welwyn Garden City AL7 2EH

Change of use from general amenity land to residential to include the alteration and extension of the existing brick wall

FULL PERMISSION Welwyn Hatfield
26 Aug 2026 Pending 6/2026/1452/FULL

51-53 London Road Woolmer Green SG3 6JE

Retrospective application for the installation of palisade fencing and gates adjoining highway.

FULL PERMISSION Welwyn Hatfield
25 Aug 2026 Under Consultation 6/2026/1498/HOUSE

6 West View Hatfield AL10 0PJ

Erection of part single part two-storey rear extension

HOUSEHOLDER APPLICATION Welwyn Hatfield
25 Aug 2026 Under Consideration 6/2026/1496/LAWP

6 West View Hatfield AL10 0PJ

Certificate of lawfulness for erection of single storey rear extension, side and rear extension, hip to gable loft conversion with rear dormer

LAWFUL DEVELOPMENT - PROPOSED Welwyn Hatfield
24 Aug 2026 Under Consideration 6/2026/1489/LAWP

23 The Ridgeway Potters Bar EN6 4BB

Certificate of lawfulness for the erection of an outhouse to accommodate gym facilities

LAWFUL DEVELOPMENT - PROPOSED Welwyn Hatfield
24 Aug 2026 Under Consultation 6/2026/1488/EM

9 Autumn Grove Welwyn Garden City AL7 4DB

Installation of 1 x Extreme uPVC french door set, Smooth White uPVC frames inside & out, Multipoint locking mechanism, Ultion High Security door cylin...

ESTATE MANAGEMENT Welwyn Hatfield
24 Aug 2026 Under Consultation 6/2026/1479/HOUSE

6 Marsden Road Welwyn Garden City AL8 6XZ

Erection of single storey side extension and part single, part two storey rear extension

HOUSEHOLDER APPLICATION Welwyn Hatfield
21 Aug 2026 Under Consultation 6/2026/1477/HOUSE

4 Brookmans Avenue Brookmans Park AL9 7QJ

Retention of single storey timber structure as gym and addition of storm porch

HOUSEHOLDER APPLICATION Welwyn Hatfield
21 Aug 2026 Under Consultation 6/2026/1472/HOUSE

16 Oak Road Woolmer Green SG3 6LS

Erection of part single, part two storey rear extension, new windows and doors to existing side and rear elevations and installation of rooflight with...

HOUSEHOLDER APPLICATION Welwyn Hatfield
20 Aug 2026 Pending 6/2026/1461/EM

469 Howlands Welwyn Garden City AL7 4HP

Removal of front hedge on boundary of property and to replace existing block paving, with new block paving with better drainage

ESTATE MANAGEMENT Welwyn Hatfield
20 Aug 2026 Pending 6/2026/1471/FULL

5 Branch Close Hatfield AL10 0TW

Garage conversion and extension to garage for use as annex

FULL PERMISSION Welwyn Hatfield
19 Aug 2026 Under Consultation 6/2026/1429/EM

62 Parkway Welwyn Garden City AL8 6HH

Replacement rear door and rear window

ESTATE MANAGEMENT Welwyn Hatfield
19 Aug 2026 Under Consultation 6/2026/1364/EM

73 Monkswood Welwyn Garden City AL8 7EF

Creation of two off-street parking spaces within the front garden by converting part of the existing lawn to a permeable surface, To include part hedg...

ESTATE MANAGEMENT Welwyn Hatfield
19 Aug 2026 Pending 6/2026/1467/LB

3 Holly Hall Court Church Street Welwyn AL6 9LH

Replacement like-for-like front door and one window

LISTED BUILDING Welwyn Hatfield
19 Aug 2026 Pending 6/2026/1442/EM

16 Stanborough Green, Welwyn Garden City, AL8 6XQ

Replaced double glazing (front and back) - like-for-like replacement. Replaced front door

ESTATE MANAGEMENT Welwyn Hatfield
19 Aug 2026 Pending 6/2026/1466/HOUSE

36 Warren Way Digswell Welwyn AL6 0DN

Erection of two storey side extension, part single/two storey rear extension, insertion of two front dormer windows and front porch following the demo...

HOUSEHOLDER APPLICATION Welwyn Hatfield
19 Aug 2026 Pending 6/2026/1459/HOUSE

16 Oak Road Woolmer Green SG3 6LS

Erection of annexe

HOUSEHOLDER APPLICATION Welwyn Hatfield
18 Aug 2026 Pending 6/2026/1450/EM

168 Blythway Welwyn Garden City AL7 1DU

Refurbishment and upgrade of existing rendered, gable wall, with the application of a ‘breathable’ top silicone coat for durability and longevity

ESTATE MANAGEMENT Welwyn Hatfield
18 Aug 2026 Pending 6/2026/1438/EM

203 Handside Lane Welwyn Garden City AL8 6TE

Rebuilding conservatory at the rear of the house and replacement of the rear kitchen door with a window

ESTATE MANAGEMENT Welwyn Hatfield
18 Aug 2026 Pending 6/2026/1437/LAWP

49 Bradgate Cuffley Potters Bar EN6 4RP

Certificate of lawfulness for garage conversion with side access door

LAWFUL DEVELOPMENT - PROPOSED Welwyn Hatfield
18 Aug 2026 Pending 6/2026/1456/HOUSE

8 The Limberlost Welwyn AL6 9TS

Erection of single storey side extension and front porch canopy

HOUSEHOLDER APPLICATION Welwyn Hatfield
17 Aug 2026 Pending 6/2026/1301/LAWP

20 Kingsmead Cuffley Potters Bar EN6 4AN

Certificate of lawfulness for the erection of an outbuilding and double garage within the curtilage of existing dwelling including formation of drivew...

LAWFUL DEVELOPMENT - PROPOSED Welwyn Hatfield
14 Aug 2026 Pending 6/2026/1433/HOUSE

117 Stonecross Road Hatfield AL10 0HS

Erection of part single, part two storey rear extension with insertion of window to side elevation

HOUSEHOLDER APPLICATION Welwyn Hatfield
14 Aug 2026 Pending 6/2026/1339/EM

241 Daniells Welwyn Garden City AL7 1QD

Erection of single storey rear extension following demolition of conservatory & alterations to openings

ESTATE MANAGEMENT Welwyn Hatfield
13 Aug 2026 Pending 6/2026/1427/FULL

45 Great Dell Welwyn Garden City AL8 7HP

Change of use of amenity land to driveway area with part hedge removal, part two storey rear extension, roof lantern to existing kitchen roof and alte...

FULL PERMISSION Welwyn Hatfield
13 Aug 2026 Pending 6/2026/1428/HOUSE

7 Pleasant Rise Hatfield AL9 5DR

Erection of single storey rear garage extension

HOUSEHOLDER APPLICATION Welwyn Hatfield
12 Aug 2026 Pending 6/2026/1417/HOUSE

15 Ramsey Close Brookmans Park AL9 6NP

Erection of single storey side and first floor rear extensions, front porch extension, door and fenestration alterations to rear elevation, new front ...

HOUSEHOLDER APPLICATION Welwyn Hatfield
12 Aug 2026 Pending 6/2026/1423/LAWP

57 Tolmers Road Cuffley Potters Bar EN6 4JG

Certificate of lawfulness for the erection of an outbuilding

LAWFUL DEVELOPMENT - PROPOSED Welwyn Hatfield
11 Aug 2026 Pending 6/2026/1408/HOUSE

Wytmead Essendon Hill Essendon Hatfield AL9 6AW

Reinstatement of the previously truncated chimney

HOUSEHOLDER APPLICATION Welwyn Hatfield
11 Aug 2026 Pending 6/2026/1418/LAWP

49 Tolmers Road Cuffley Potters Bar EN6 4JG

Certificate of lawfulness for installation of rear dormer

LAWFUL DEVELOPMENT - PROPOSED Welwyn Hatfield
11 Aug 2026 Pending 6/2026/1414/EM

48 Woodhall Court Welwyn Garden City AL7 3TD

Replacement of leaning back garden brick wall with a close board fence and access gate to back garden

ESTATE MANAGEMENT Welwyn Hatfield
11 Aug 2026 Pending 6/2026/1362/EM

135 Howlands Welwyn Garden City AL7 4RL

Installation of hardstanding

ESTATE MANAGEMENT Welwyn Hatfield
11 Aug 2026 Pending 6/2026/1361/EM

31 Brockswood Lane Welwyn Garden City AL8 7BE

Erection of part single storey part two storey rear extension, garage conversion and installation of air conditioning unit mounted at ground floor on ...

ESTATE MANAGEMENT Welwyn Hatfield
7 Aug 2026 Under Consultation 6/2026/1405/FULL

Sopers House Sopers Road Cuffley Potters Bar EN6 4RY

Enclosure of roof terrace including part for meeting room and front portico to entrance with terrace above

FULL PERMISSION Welwyn Hatfield
7 Aug 2026 Pending 6/2026/1399/PN8

1 High Dells Hatfield AL10 9JD

Prior approval for a single storey rear extension measuring 4.50m in depth, 2.58m to the eaves and the maximum height of 2.75m

Class A – enlargement, improvement or other alteration of a dwellinghouse - PRIOR APPROVAL Welwyn Hatfield
7 Aug 2026 Pending 6/2026/1264/FULL

53 Brookmans Avenue Brookmans Park AL9 7QG

Erection of dwelling with boundary wall and gates following demolition of existing property

FULL PERMISSION Welwyn Hatfield
6 Aug 2026 Pending 6/2026/1376/HOUSE

18 Briary Wood Lane Welwyn AL6 0TF

Erection of a single storey ground floor extension & part two storey rear, raising the roof and alterations to facilitate loft conversion to include n...

HOUSEHOLDER APPLICATION Welwyn Hatfield
6 Aug 2026 Pending 6/2026/1392/HOUSE

1 Little Wade Welwyn Garden City AL7 4LE

Erection of a single storey rear extension

HOUSEHOLDER APPLICATION Welwyn Hatfield
5 Aug 2026 Pending 6/2026/1390/HOUSE

38 Butterwick Way Welwyn AL6 9GH

Loft conversion with side facing dormer and 4 roof lights

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.