Loft conversion: turning roof space into a room you can use

A rooflight conversion keeps the roof shape and adds windows in the slope. It is the least disruptive, but only works where there is already enough head height under the ridge. A rear dormer adds a box-shaped extension to the back slope, creating full-height floor area, and is the most common type on terraced and semi-detached houses. A hip-to-gable conversion rebuilds a sloping side roof as a vertical gable wall, often combined with a rear dormer. A mansard changes the whole rear slope to a near-vertical wall and nearly always needs planning permission.

The right type depends on the roof shape and pitch, how much head height there is, where the stairs can land and what the council will accept. Measure from the top of the ceiling joists to the underside of the ridge before you ask anyone for a price, and mention whether there are water tanks, a chimney breast or roof trusses rather than traditional rafters.

Many loft conversions on houses need no planning application because they fall under permitted development, Class B of the General Permitted Development Order. The Planning Portal lists the conditions: the extra roof space, including any earlier roof enlargement, must not exceed 40 cubic metres on a terraced house or 50 cubic metres on other houses; the enlargement must not rise above the existing roof or extend beyond the roof slope at the front where it faces a highway; materials must look similar to the house; balconies, verandas and raised platforms are excluded; and side-facing windows must be obscure-glazed and, if they open, only above 1.7 metres from the floor.

A dormer must, so far as practicable, be set back at least 20 centimetres from the original eaves, and must not overhang the outer face of the wall. Flats and maisonettes have no permitted development rights for this, and neither do houses in conservation areas, National Parks, the Broads, World Heritage Sites or areas of outstanding natural beauty. Councils can also remove the rights locally. A Lawful Development Certificate from the council confirms that your plans are permitted development, which helps when you sell. Wales, Scotland and Northern Ireland have their own rules.

Source: planningportal.co.uk

Building Regulations approval is needed to turn a loft into a liveable room, even when planning permission is not. The existing ceiling joists are rarely strong enough to be a floor, so new, deeper joists are added and often supported on steel or timber beams. Rafters cut for windows or a dormer need trimming and strengthening, and the loads must be carried down to walls and foundations able to take them.

The new floor needs a proper staircase; retractable ladders are not acceptable. Approved Document K allows reduced headroom over loft stairs where 2 metres cannot be achieved: 1.9 metres at the centre of the stair and 1.8 metres at the side. An alternating tread stair is only allowed where there is no room for a normal stair and it serves just one habitable room, plus a bathroom or WC if that is not the only WC in the house.

Fire safety is the biggest change for most families. On a typical two-storey house, the stairway from the new loft room down to the front door has to be protected, usually with fire-resisting doors onto it and sometimes new partitions, because escape from windows above first-floor level is too dangerous. Mains-powered, interlinked smoke alarms are needed in the stairway at each level. Sound insulation between the loft and the rooms below is also checked.

• drawings and structural calculations, and who produces them
• the Building Control route and who submits the application
• steel beams, padstones and any work to party walls
• staircase design, with headroom shown
• fire doors and any changes to the existing stairway
• insulation, ventilation of the roof and new windows
• electrics, heating and any bathroom plumbing in the loft

On terraced and semi-detached houses, steel beams are often set into the party wall, and the wall may be built up for a hip-to-gable conversion. Under the Party Wall etc. Act 1996, which applies in England and Wales, you must give notice to the neighbour between 2 months and a year before the work starts. The neighbour has 14 days to consent in writing; if they do not respond or do not agree, surveyors are appointed to agree a party wall award. Allow for this in the timetable.

Bats roost in roof spaces and are a protected species. If there are signs of them, a survey may be needed, and if bats are using the building, a licence may be required before work goes ahead.

Source: gov.uk

Tell us the house type, the roof shape, the head height if you have measured it, and whether you already have drawings or approvals. After you confirm your phone number and email address, loft conversion businesses in your area can see the job without your details. Exactly one can buy it, and it then leaves our list. We email you that business's name, address and phone number before it sees your contact details. You pay nothing, no business is obliged to take it, and unsold requests are withdrawn after 21 days. Offrano checks that buyers are registered businesses only, so ask who designs the structure and which Building Control body signs off the work.