Welwyn Garden City, Hertfordshire
Rear extension planning drawings in Welwyn Garden City
Rear extension planning drawings in Welwyn Garden City: measured survey, design options, planning drawings and the application, handled for you. We measure the house, show you what the rules allow, price it in writing and build it.
Welwyn Garden City is covered from our Hertfordshire round, including AL7 and AL8. For Welwyn Garden City homes we start with a measured survey, then draw options before anything is submitted.
Book a free site visit
Tell us about the house and we'll call to arrange a free, no-obligation visit.
What do rear extension planning drawings cost in Welwyn Garden City?
As a guide, £1,000–£2,500 including VAT for a single-storey rear extension, or £2,000–£3,500 for a two-storey scheme. A householder planning application in England costs £548 (£575 for applications made from 8 December 2026), and a lawful development certificate for proposed work costs half the householder fee. Your written price follows a measured survey and an agreed design, so it reflects your house, not an average.
Do you need planning permission for a rear extension in Welwyn Garden City?
Planning for a rear extension in Welwyn Garden City follows the English householder rules.
England's rules allow a rear extension of more than one storey without an application only when it is no deeper than 3 metres and at least 7 metres from the boundary opposite the rear wall, and never on designated land. Most two-storey schemes need householder planning permission.
Councils aim to decide householder applications within 8 weeks of validation, and prior approval within 42 days.
Conservation areas, National Parks, National Landscapes and the Broads restrict permitted development, and listed buildings always need listed building consent. We check your house's planning history and any conservation area before drawing, so the route is clear before you spend on plans.
What are homes in Welwyn Garden City like to extend?
Welwyn Garden City mixes Victorian terraces with 1930s semis, so both side returns and full-width kitchen extensions suit houses here.
How a rear extension in Welwyn Garden City comes together
Survey visit
We visit free of charge, measure up, check access, drainage and neighbours' extensions, and note what you want the room to do.
Options and costs
We draw layout options and price each one, so the budget shapes the design rather than surprising you later.
Planning and regulations
We take the design through the right planning route, then produce the construction drawings and engineer's calculations for building control.
Written price, then build
Once the design and approvals are in place, you get a fixed written price and programme, and we build through to sign-off.
Rear extension planning drawings near Welwyn Garden City
From Welwyn Garden City, the nearest places we also cover are Hatfield (2.8 miles) and Codicote (3.6 miles).
- Rear extension planning drawings in Hatfield
- Rear extension planning drawings in Codicote
- Rear extension planning drawings in Hertford
- Rear extension planning drawings in St Albans
- Rear extension planning drawings in Harpenden
Other work in Welwyn Garden City:
FAQ
Rear extension planning drawings questions in Welwyn Garden City
What postcode areas do you cover around Welwyn Garden City?
Including AL7 and AL8, and the surrounding Hertfordshire area.
Can I live at home while the extension is built?
Usually yes. Most of the work is outside until the back wall is opened near the end, and that stage is screened off.
Do neighbours get consulted?
Yes for a full application: the council writes to them or puts up a site notice.
What do rear extension planning drawings cost in Welwyn Garden City?
As a guide, £1,000–£2,500 including VAT for a single-storey rear extension and £2,000–£3,500 for a two-storey scheme, covering the measured survey, design options and the application. The council fee is extra.
Do you handle building control in Welwyn Garden City?
Yes. We apply to the council or a registered building control approver and hand over the completion certificate.
How long does a rear extension take to build in Welwyn Garden City?
Most single-storey rear extensions take 10 to 16 weeks on site and two-storey extensions 16 to 26 weeks, after design and approvals.