Porch Construction near you

Class D of Part 1 of Schedule 2 to the Town and Country Planning (General Permitted Development) (England) Order 2015 permits the erection or construction of a porch outside any external door of a dwellinghouse. Development is not permitted if the ground area, measured externally, would exceed 3 square metres; if any part would be more than 3 metres above ground level; or if any part of the porch would be within 2 metres of any boundary of the curtilage of the dwellinghouse with a highway.

Those three limits do most of the work, and the third is the one that catches terraced and older suburban houses, where the front wall stands close to the pavement. A highway for this purpose includes the footway, so a house whose front door is less than two metres back from the pavement boundary cannot have a permitted development porch on the front at all, however small. It can still have one - it just needs a planning application.

The Planning Portal notes the usual exclusions. The rules do not apply to flats and maisonettes, nor to houses created through a permitted development change of use, and they do not apply where a planning condition, an article 4 direction or another restriction limits permitted development rights. A listed building needs listed building consent, and in a conservation area the appearance of anything on the front elevation is looked at far more closely. This is England; the other three nations set their own limits.

Below ground, a porch needs a foundation like any other structure, and on a British house that usually means trench fill down to a depth that satisfies the ground conditions, taking account of any tree nearby. It is small, so the foundation is a modest cost; it is also close to the house, so the relationship between the new foundation and the existing one is the part the builder should be talking about rather than the colour of the bricks.

Above ground, the choice is between a brick or blockwork base with glazing above, a fully glazed uPVC or aluminium structure, and a timber-framed porch with a tiled roof. Matching the existing house is not a legal requirement under Class D the way it is for a roof addition, but it is what determines whether the porch looks like part of the house or like something delivered on a lorry. Brick courses that line through with the existing, a roof pitch that echoes the main roof, and a fascia detail that does not cut across a bay window are what separate the two.

The floor is the part most often skimped. A porch floor needs a damp proof membrane linked to the damp proof course of the house, and a threshold detail that keeps water out while remaining safe to walk over. Where the porch floor sits at the level of the existing front step, that junction is where rain blows in.

The single decision that changes the character of a porch is whether the original front door stays. Keeping it gives you the lobby effect - two doors, an air gap, and a genuine reduction in draughts - and it keeps the building regulations position simple, because the heated envelope of the house is still the old door line. Removing it makes the porch part of the hall, which means the porch now has to perform as an external wall and the work has stopped being an exempt porch.

Security follows the same logic. A porch with a glazed outer door and no inner door means the front door of the house is now a piece of glass, and insurers, who assess the security of the final door line, take a view on that. If the outer door is the only door, it needs to be a proper external door with proper locking.

Escape is the third consideration and it is the one people forget. The front door is the final exit for the house. A porch that turns a single door into a sequence of two doors with a key-operated lock on the outer one can slow escape in a fire, particularly at night. Thumb-turn locking on the inner face of the outer door, and a habit about where keys live, are worth more than any amount of glazing specification.

A porch is priced on ground conditions, construction and detailing rather than on size, because the sizes are all small. What moves it: how deep the foundation has to go and whether a tree or a drain is in the way, whether the structure is glazed, brick-based or timber-framed, how the roof ties into the existing house and whether the bay or the eaves complicate it, the glazing and door specification, what happens to the existing threshold and step, and whether any electrical work is included. A porch that has to match a Victorian frontage costs more than one on a plain flat elevation for reasons that have nothing to do with square metres.

LokalMatch is simply the way you meet the builder. Set out what you want once, including your postcode and a photograph of the front of the house, and firms working nearby will contact you directly. The service is free to homeowners, and the pros pay for the requests that reach them. LokalMatch does not build, does not price the work and does not vet, rank or recommend any of the businesses that respond, so it is worth asking to see a porch they have finished on a house like yours.