Porch extensions in Barnet
A porch extension in Barnet starts with the right design and the right approval route. We take care of both, then build it with our own project management.
- Guide price in BarnetFrom £5,200 inc VAT
- PlanningUsually permitted development under 3 m²
- Build time2–4 weeks on site
- Postcode districtsEN4, EN5, N20

Do I need planning permission in Barnet?
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 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).
How much does a porch extension cost in Barnet?
For Barnet 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 |
Try the guide-price tool to see a range for your own size and finish.
Included in a typical project
- Front door, glazing and electrics
- Planning check against the porch limits
- Foundations and drainage for rainwater
- Brick, render or oak frame walls
- Tiled, slate or flat roof
Covering Barnet
Across EN4, EN5, N20, we can visit, measure and advise. We also work in nearby East Barnet (2 miles), Friern Barnet (3 miles), Finchley (3 miles), Palmers Green (4 miles).
Just over the Hertfordshire border, Potters Bar is about 3 miles away. In London, space is at a premium and gardens are often short, so side returns, wraparounds and carefully planned rear extensions tend to make the most of every metre.
From first visit to completion
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
Work is carried out to the agreed programme, inspected by building control and signed off at the end.
Your questions about a porch extension in Barnet
Will my neighbours in Barnet 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.
Can I see a price before committing to anything?
Yes. The guide prices on this page are adjusted for Barnet, and the guide-price tool gives a range for your own size. After the survey you get a written price before anything is agreed.
Who do I contract with for a porch extension in Barnet?
Your contract is with S&K Property Investments and Improvement Ltd, which designs and manages the project and the build teams who carry it out.
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 Barnet
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.