Building a porch: costs and hiring a builder

A guide to commissioning a porch build: permissions, hiring the right professionals in order, realistic costs, and avoiding poor builders.

MW-01What building a porch actually involvesA porch adds a small enclosed space at your front (or back) door, usually with its own foundations, walls or frame, a roof, and a door. It can be a simple UPVC box or a brick-built structure that matches your house. Because it touches your house's foundations, walls and roofline, it's treated as building work, not a DIY add-on, and needs proper professional input.

MW-02Check if you need planning permissionMany porches fall under 'permitted development' and don't need planning permission, but only if they stay under set size and height limits and keep a set distance from the road. If your porch is larger, closer to a boundary or your house is listed or in a conservation area, you'll need planning permission from your local council. Don't assume — get this checked before you design anything.

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KNOW THE RULES

Planning permission may be required depending on size, position and your property's status. HomeGraft has a 'Know the rules' guide on planning permission for extensions and porches.

MW-03Building Regulations and Party Wall checksSmall porches are often exempt from Building Regulations if they're under a certain floor area and the original external door stays in place. But if the builder knocks a new opening in your house wall, that opening still needs Building Control sign-off, exemption or not. If the porch sits near a shared boundary with a semi-detached or terraced neighbour, the Party Wall Act may also apply to the foundations.

RULES

KNOW THE RULES

Structural openings in the house wall need Building Control approval even if the porch itself is exempt. Foundation work near a shared boundary may require a Party Wall notice to your neighbour under the Party Wall Act.

MW-04Hire professionals in the right orderStart with a structural engineer if a wall opening or roof tie-in is involved — they work out what's safe before anyone prices the job. Next, sort planning permission if needed, then submit to Building Control (either the council or a registered building control approver) before work starts. Only then should you get builder's quotes, because they need the final drawings and structural calculations to price accurately.

MW-05Realistic costs and timescalesFor an average three-bedroom house outside London in 2026, expect roughly £3,000–£6,000 for a simple UPVC porch, £6,000–£12,000 for a brick-built porch with a pitched roof, and £10,000–£18,000+ for a larger or bespoke glazed design. Costs climb towards the top of the range for matching existing brickwork, bespoke roof shapes, poor ground conditions needing deeper foundations, added electrics, and scaffolding. London and the South East typically run 20–40% higher. Allow 4–8 weeks for design and permissions, then 1–3 weeks for the build itself once it starts.

MW-06What a good quote should containA proper quote itemises groundwork, foundations, brickwork or frame, roof, door, glazing and any electrics separately, not as one lump sum. It should state whether VAT is included, give a start and finish date, set out a staged payment schedule (not a large deposit upfront), and say clearly who is responsible for submitting Building Control paperwork. Ask to see the drawings or specification the quote is based on.

MW-07Questions to ask, and red flagsAsk: Are you insured for public liability? Will you handle the Building Control notice? Can I see photos of similar porches you've built, and speak to a recent customer? What's your process if something needs fixing after completion? Red flags include cash-only pricing, no fixed business address, reluctance to put anything in writing, demands for a large upfront payment, and vague or dismissive answers about Building Regulations.

MW-08What commonly goes wrongCommon problems include foundations that don't go deep enough for the local ground conditions, roof junctions that leak where the porch meets the house, and a missing damp proof course causing damp inside. Skipping Building Control entirely is a frequent mistake — it can cause real problems later when you try to sell the house, since buyers' solicitors ask for completion certificates. Boundary disputes with neighbours also arise when foundations are dug without notice.

MW-09If you live in Wales, Scotland or Northern IrelandIn Wales, planning permission rules are similar to England but Building Regulations are managed separately through Welsh Building Regulations. In Scotland, a small porch of up to 8 m², at least 1m from the boundary and with no heater, flue or toilet, usually doesn't need a building warrant. Bigger porches do, and you must have the warrant before work starts. In Northern Ireland, Building Regulations and planning are handled by local councils under different legislation, so always check with them directly before commissioning work.

RULES

KNOW THE RULES

In Scotland, larger porches need a building warrant from the local council before work begins.

KNOW THE RULES

Before you start: Do I need planning permission for a porch?

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