Barnes porch extensions, designed and built
If you live in Barnes and want more space without moving, a porch extension is one of the most practical ways to get it. We handle the drawings, approvals and the build.
- Guide price in BarnesFrom £5,200 inc VAT
- PlanningUsually permitted development under 3 m²
- Build time2–4 weeks on site
- Postcode districtsSW13, SW14, SW15, TW9, W4
Planning and approvals in Barnes
In England a porch is usually permitted development if its ground floor area is no more than 3 m² measured externally, no part is over 3 m high, and no part is within 2 m of a boundary next to a road.
Before any drawing is finalised we check whether the house is listed, in a conservation area or subject to an Article 4 direction.
Building regulations approval is separate from planning. In England you can use the council's building control team or a registered building control approver; a full plans application gets the drawings checked before work starts, and the inspector signs the work off with a completion certificate.
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).
Guide prices for Barnes
For Barnes we adjust our national guide rates by ×1.3, the factor we use for London. Figures include VAT; your written quote after the survey replaces them.
| Option | What it covers | Guide price |
|---|---|---|
| Essential | Small brick or glazed porch, up to 3 m² | £5,200 – £8,450 |
| Standard | Brick porch with tiled roof and composite door | £7,800 – £12,350 |
| Premium | Larger porch with WC or oak frame and premium glazing | £11,700 – £19,500 |
For a figure based on your own dimensions, use our guide-price tool.
What we take care of
- Brick, render or oak frame walls
- Tiled, slate or flat roof
- Front door, glazing and electrics
- Foundations and drainage for rainwater
- Design to suit the house style
- Planning check against the porch limits
Covering Barnes
Our survey diary covers Barnes, including SW13, SW14, SW15, TW9, W4, W6. Neighbouring towns we cover include Chiswick (1 mile), Roehampton (2 miles), Putney (2 miles), Fulham (2 miles).
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
We visit your Barnes home, measure up, talk through what you want and check the planning position.
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
We build it with one project manager, book the building control inspections and hand over the completion certificate.
Questions people ask about porch extensions
Can I see a price before committing to anything?
Yes. The guide prices on this page are adjusted for Barnes, and the guide-price tool gives a range for your own size. After the survey you get a written price before anything is agreed.
How long does a porch extension take to build in Barnes?
On site, typically 2 to 4 weeks once approvals are in place. Before that, allow 2–8 weeks design and approvals.
Do I need building regulations approval in Barnes?
Yes. Almost every extension needs it, whatever the planning route. We prepare the drawings and book the inspections.
How much does a porch cost?
Our guide range is about £5,200 to £19,500 including VAT, depending on size, materials and whether it includes a WC.
Do I need planning permission for a porch?
In England a porch is usually permitted development if its ground floor area is no more than 3 m² (measured externally), no part is higher than 3 m, and no part is within 2 m of a boundary next to a highway. Other nations have similar but separate rules.
Book a free site visit in Barnes
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.