A porch is one of the smallest extensions you can add to a house, but in Cornwall it can make a big difference. It gives you somewhere to leave wet coats, muddy boots, surfboards and dog leads, stops wind and rain blowing straight into the hall, and can lift the look of the front of a house.
This guide explains the rules on porches, the design points that matter on an exposed Cornish site and what affects the cost. It is general guidance only, so always check the position for your property with Cornwall Council.
Do you need planning permission for a porch?
Many porches on houses can be built under permitted development, without a planning application, provided they meet all of these limits:
Floor area: the ground floor area, measured externally, must not exceed three square metres.
Height: no part of the porch may be more than three metres above ground level.
Distance from the highway: no part of the porch may be within two metres of a boundary between the house and a highway, which includes roads, pavements and many public footpaths.
Position: the permitted development right covers a porch outside any external door of the house.
Permitted development rights for porches do not apply to flats or maisonettes, and they can be removed by a planning condition or an Article 4 direction. Some converted buildings, such as barn conversions, may also have no permitted development rights. If your porch would be bigger, taller or closer to the road than the limits allow, you will need planning permission. Our permitted development guide explains the wider rules, and our guide to planning permission in Cornwall covers the application process.
Listed buildings, conservation areas and National Landscapes
If your home is listed, a porch is very likely to need listed building consent, even if it is small. See our listed building renovation guide. In conservation areas and the Cornwall National Landscape, check for any Article 4 direction and think carefully about design, because the front of a house is the most visible part. Our guide to building in an AONB or conservation area explains more. If in doubt, a Lawful Development Certificate gives formal confirmation that a porch is permitted development.
Do porches need Building Regulations approval?
Many small porches are exempt from Building Regulations, but only if they meet certain conditions. As a general guide, a porch is usually exempt where:
it is at ground level and has a floor area of under 30 square metres
it is separated from the house by external-quality walls, doors or windows, so the existing front door stays in place
the house's heating system is not extended into it
any glazing meets the safety glazing requirements of the Building Regulations
If you remove the front door to open the porch into the hall, extend the heating into it, or make level access to the house worse, Building Regulations approval is likely to be needed. Our Building Regulations guide explains how to check with Building Control. If the porch would be built over or near a public sewer, a build-over agreement with South West Water may be needed.
Designing a porch for the Cornish weather
A porch in Cornwall has to cope with wind-driven rain, salt air on the coast and the occasional storm. Good design points include:
Orientation: if your front door faces the prevailing south-westerly wind, a side-opening porch door can help.
Roof form: pitched roofs in slate, or in tiles to match the house, shed rain well and tend to suit Cornish homes better than shallow felt roofs.
Walls: stone or render plinths with glazing above, or fully built porches in stone, block and render or timber cladding, all work when detailed properly.
Doors and windows: choose units rated for exposed sites, with good seals and robust hardware.
Drainage and thresholds: make sure water drains away from the threshold and that the floor level works with the existing step.
Storage: benches, boot racks and coat hooks make the most of a small space.
Our guide to weatherproofing coastal homes covers suitable materials, and our stone, rendering and lime work service can help match a porch to a stone or rendered house.
Foundations and groundwork
Even a small porch needs proper foundations, a damp-proof course and a floor that ties in with the house. On older Cornish homes, the existing walls may be solid stone without a damp-proof course, so the junction needs careful detailing to avoid trapping moisture. See our groundworks and foundations service and our guide to damp in Cornish homes.
What affects the cost of a porch?
Every porch is different, so treat any figures you see as general guidance only. The main factors are:
size and whether you need planning permission or Building Regulations approval
the materials, for example stone or brick against render or timber
the roof type and covering
the quality of doors and glazing
groundwork, drainage and any changes to steps or paths
electrics, such as lighting and sockets
A detailed quote after a site visit is the only reliable way to price a porch. Our guide to reading a builder's quote explains what to look for.
Frequently asked questions
How big can a porch be without planning permission?
Under permitted development, up to three square metres of floor area, no higher than three metres, and not within two metres of a boundary with a highway. Check with Cornwall Council if unsure.
Can I have a porch on a flat?
Permitted development rights for porches do not apply to flats or maisonettes, so a planning application would normally be needed.
Is a porch worth it?
For many Cornish homes, yes. It adds storage, reduces draughts and heat loss at the front door, and can improve kerb appeal.
Planning a porch? Talk to us
Cornish Building Company builds porches and extensions across the whole of Cornwall. See our home extensions service and the areas we cover. Call us on 01208 816991 or contact us to talk through your ideas.
