Extension plans and drawings across Southall
We prepare extension plans and drawings for homes in Southall, as a stand-alone service or as the first stage of a design and build project.
- Guide price in SouthallFrom £1,550 inc VAT
- PlanningWe find the right route for you
- Timescale2–6 weeks for drawings
- Postcode districtsTW5, UB1, UB2, UB3, UB4
Design and approval fees for Southall
Fees below are our Southall guide (×1.3, the London factor), including VAT. Council and building control fees are extra.
| Option | What it covers | Guide price |
|---|---|---|
| Essential | Measured survey and planning drawings | £1,550 – £2,900 |
| Standard | Planning drawings plus building regulations drawings | £2,850 – £4,950 |
| Premium | Full pack with structural calculations and 3D visuals | £4,400 – £7,150 |
For a figure based on your own dimensions, use our guide-price tool.
What we take care of
- Measured survey of the house and garden
- Two or three layout options to compare
- 3D views to check the look and the light (full pack)
- Planning drawings: existing and proposed plans and elevations, site and location plans
The most expensive changes are the ones made after the steel is ordered. A good design stage settles layout, heights, glazing and services on paper, so the build price is firm.
Planning and approvals in Southall
In England the main routes are permitted development (ideally confirmed with a lawful development certificate, £274), larger home extension prior approval (£249, 42 days) and a householder planning application (£548, normally 8 weeks), with council fees as set from 1 April 2026.
Before any drawing is finalised we check whether the house is listed, in a conservation area or subject to an Article 4 direction.
Building over or within 3 m of a public sewer needs the water company's consent, usually through a build-over agreement, before the foundations go in.
If the work involves a shared wall, building on the boundary, or digging foundations within 3 m (sometimes 6 m) of a neighbour's building, the Party Wall etc. Act 1996 applies and notice must be served before work starts: two months for work to a party wall, one month for new walls on the boundary and for excavations.
Applications are decided by the local planning authority (your district, borough or unitary council).
Extensions in and around Southall
Postcode districts we cover around Southall include TW5, UB1, UB2, UB3, UB4, W7. Neighbouring towns we cover include Greenford (2 miles), Heston (2 miles), Hayes (Hillingdon) (2 miles), Isleworth (3 miles).
For homes towards Surrey, Ashford, Surrey is around 7 miles away. Across London, terraced houses with narrow side returns and tight access are the norm, which shapes everything from party wall notices to how materials reach the back garden.
Our process, step by step
Site visits are free and there is no obligation. Where drawings are needed, the design stage is priced in writing before it starts.
Free site visit
First, a site visit: we look at the house, garden, access and drains and listen to what you need.
Design and approvals
We produce the drawings and structural design, and manage the approvals so they are in place before work starts.
Fixed written price
We confirm the build price in writing, based on the approved drawings and the finishes you have chosen.
Build and sign-off
The build is managed from start to finish, inspected at each stage and signed off on completion.
Common questions in Southall
Can I see a price before committing to anything?
Yes. The guide prices on this page are adjusted for Southall, and the guide-price tool gives a range for your own size. After the survey you get a written price before anything is agreed.
Do you cover all of Southall?
Yes. We cover Southall and the surrounding parts of Greater London. Site visits are free and there is no obligation.
Will my neighbours in Southall be involved?
If a planning application or prior approval is needed, the council notifies neighbours. If the work is on or near a shared boundary, party wall notices may also be needed.
How much do extension plans cost?
Our design packs range from about £1,550 to £7,150 including VAT, from planning drawings only to a full pack with building regulations drawings, structural calculations and 3D views. Council fees are separate.
Do I need an architect?
Not necessarily. For most extensions an experienced designer or architectural technologist is enough. For listed buildings or complex sites an architect’s input can help.
Book a free site visit in Southall
We will measure up, check the planning position and give you honest guide figures.
- Free, no-obligation site visit
- Planning route checked before you spend on drawings
- Written price once the design is agreed
- Building control sign-off at the end
Prefer to talk? Call 0800 088 6341 or .
Book a free site visit
Tell us a little about the project and we will arrange a time.