If your answer is no, never fear, because our project checklist is here! Structural Stability The roof structure, including the floor needs to be of adequate strength for use as a habitable room and this will need to be calculated by a structural engineer or specialist loft contractor to ensure compliance with the building regulations.
The existing ceiling joists aren't likely to be strong enough for use as the new floor.
These are usually strengthened by adding floor joists alongside the existing ceiling joists, spanning across structural walls on the floor below.
Where headroom is limited, it will pay to keep any increase in the depth of the floor structure to a minimum by using shorter length joists spanning off structural walls.
In some instances where the ridge height of the existing roof cannot be raised for planning reasons it may even be worth lowering the existing first floor ceilings to create additional headroom in the attic.
Fire Safety The building regulations require there to be a safe means of escape in the event of fire from any storey with a floor level more than 4.
5m above ground level.
This is usually achieved by creating an enclosed staircase that will resist fire for at least 30 minutes.
This usually means upgrading the walls, floor and ceiling of the hallway housing the stairs, and changing or upgrading doors to give 20 minutes of fire protection and adding automatic door closers.
An alternative and more common solution, is to protect the staircase enclosure to a reduced performance and to add an egress window, escape window, into each habitable attic room, bedrooms but not bathrooms.
This allows you to keep existing doors, providing they are fitted with automatic closers.
Escape windows must have a clear opening span of at least 450mm x 450mm and be in a position where there is an acceptable escape route.
Either way, the attic conversion must be separated from the rest of the house by a fire door with an automatic closer and the structure must have 30 minutes fire resistance (a stud wall with 15mm plasterboard on both faces is sufficient) and a hard-wired (connected to the mains) smoke detector.
Ventilation New attic rooms need to have both an openable window to give 'rapid ventilation' (minimum 1/20 th of the floor area) and background ventilation via a whole-house ventilation system, trickle vents or similar air vents.
Any bathrooms must also be fitted with mechanical extraction.
The roof structure between the new insulated sloping ceilings and the roofing felt also needs to be ventilated to prevent the build up of potentially damaging moisture.
This is usually achieved by leaving at least a 50mm air gap between the insulation and the underside of the roofing felt.
This void must be ventilated at eaves and ridge.
Where the rafters are not deep enough for 55-60mm of insulation plus a 50mm air gap, it may be necessary to add battens or to use an ultra-thin foil-type insulation product combined with rigid insulation board.
Where the roof is being rebuilt or the roof covering lifted and relayed, an alternative to adding vents is to use a breathable roofing membrane.
This can eliminate the need to leave the 50mm ventilation space and add vents.
Thermal Insulation Loft rooms have to be insulated to a high standard to meet the current requirements for conservation of fuel and power.
It is generally accepted that superior insulation products have to be used, such as rigid urethane foam boards with a foil facing, or even better, rigid phenolic foam boards with a foil facing.
To achieve the minimum requirement of a U-value of 0.
3 W/m2K, it is necessary to add around 55-60mm of insulation between the rafters (leaving a 50mm clear void between the top of the insulation and underside of the roof felt) plus a further 25mm of insulation underneath the rafters covered by plasterboard.
This minimum thermal performance can be significantly improved by adding more insulation.
Acoustic Insulation The roof and external walls must meet a minimum standard of acoustic insulation.
It is also a good idea to try to reduce the sound between the new attic rooms and the floor below.
Placing mineral wool insulation in the floor structure will reduce airborne sound transfer.
Laying acoustic matting over the floor structure usually made from recycled rubber, before laying carpets or a floating floor will reduce impact sound transfer.
Staircase Access A residential attic conversion must have a permanent access staircase.
Ideally this will be a conventional staircase, however, in certain circumstances a space saver staircase, or a permanent ladder can be acceptable.
The circulation space required to reach and house a new staircase will ideally be taken from an existing hallway.
Where possible the new flight can repeat the main flight from the ground floor.
The minimum practical width for an access corridor is 900mm.
Where the space needs to be taken from existing rooms the space that is lost needs to be weighed up against the space that is lost needs to be weighed up against the space gained in the attic.
Careful consideration needs to be given to which room can afford to lose the space for the access, making sure that each room retains good proportions and is a practical, usable space.
Conventional Staircase A conventional staircase leading to an attic must meet building regulations and have treads (the horizontal part of each step) and risers (the vertical part between treads) of no more than 220mm and a maximum pitch of 42 degrees.
There is no minimum width for a staircase defined by the building regulations, but a width of 600-850mm is the practical minimum.
There should be a minimum of 2m headroom above the stairs, however, in situations where the stairs are running beneath a sloping roof this can be reduced to 1.
9m at the centre point of the flight, with a minimum of 1.
8m at the edge.
There must be a landing at the top and bottom of the stairs of the same width and depth as the width of the flight.
Doors can be fitted at the edges of the top landing, but must swing away from it (into the attic rooms).
Doors around the bottom landing can swing either way providing at least 400mm of clear space is left at the bottom of the flight.
Space-saver Staircases A space saver staircase with alternating trends is acceptable where there is only one attic room (including a bedroom with an en-suite bathroom, providing there is another bathroom elsewhere in the house).
Loft Ladders A fixed loft ladder with handrails is acceptable providing there is only a single attic room and a staircase cannot be added without altering other bedrooms.
Windows There are three options for bringing light and rapid ventilation into the roof space: gable windows, dormer windows and rooflights.
Conventional windows can be added into gable end walls, if planning permission is required, the main issues will be whether or not the window creates privacy problems due to the proximity of neighbouring properties, Creating a new window opening and fitting a double glazed window will cost around £700-800.
Dormer windows stand out from the line of the roof slope.
As they increase the volume of the house they constitute an extension and therefore require planning permission.
A dormer window will cost from £7-800 upwards depending on size, including a double glazed window unit.
A dormer window can be used to create additional headroom in the loft, often providing a solution to the shortage of headroom above staircases, a landing area or for bathrooms.
Rooflights are windows that are fitted in line with the pitch (slope) of the roof.
Rooflights can usually be inserted without requiring planning permission.
A rooflight can add around 200mm of headroom, sufficient in some instances to overcome the shortage of headroom above a staircase, or for a landing area.
A standard rooflight, fitted, costs from £4-500 upwards depending on size.
Special Rooflights Rooflights are available in large sizes and several can be combined to rooflights form feature windows.
Models are available that open up to comply with regulations for fire escape windows, and others open up to form a balcony.
Where conventional rooflights are not acceptable, for instance on listed buildings and in conservation areas, conservation rooflights may be acceptable.
These are designed to mimic traditional cast iron rooflights that sit flush with the roofline.
In addition, lightpipes channel light through mirrored ducting into rooms where other forms of natural lighting may be unsatisfactory.
Heating, Plumbing and Electrics Providing the boiler has sufficient output, new radiators for the attic rooms can usually be added to the existing central heating system.
Any water storage tanks in the existing loft will have to be moved or replaced to make room for the conversion.
Where there is no space to move the tanks elsewhere in the loft (gravity-fed systems have to be higher than the highest outlet or radiator in order to work) an alternative is to upgrade to a modern pressurised (unvented) plumbing system that does not require header tanks.
The choice is between a combination boiler which will fire the central heating plus provide hot water on demand, or a system boiler to fire the central heating, plus a pressurised hot water storage cylinder which can be located anywhere in the house.
New power points and lighting circuits can usually be added to existing circuits or on new circuits added to the existing consumer board.
Domestic wiring is now covered by the building regulations and if the existing wiring needs upgrading, this work will have to be done at the same time as the new wiring for the loft conversion.
Exclusions Mezzanine attic rooms, an open gallery covering an area of less than 50% of the floor below, have more relaxed fire regulations providing the space is non-habitable room.
Loft conversions above bungalows are also excluded from most of the regulations, although the staircase must still lead directly to an external door.
The existing ceiling joists aren't likely to be strong enough for use as the new floor.
These are usually strengthened by adding floor joists alongside the existing ceiling joists, spanning across structural walls on the floor below.
Where headroom is limited, it will pay to keep any increase in the depth of the floor structure to a minimum by using shorter length joists spanning off structural walls.
In some instances where the ridge height of the existing roof cannot be raised for planning reasons it may even be worth lowering the existing first floor ceilings to create additional headroom in the attic.
Fire Safety The building regulations require there to be a safe means of escape in the event of fire from any storey with a floor level more than 4.
5m above ground level.
This is usually achieved by creating an enclosed staircase that will resist fire for at least 30 minutes.
This usually means upgrading the walls, floor and ceiling of the hallway housing the stairs, and changing or upgrading doors to give 20 minutes of fire protection and adding automatic door closers.
An alternative and more common solution, is to protect the staircase enclosure to a reduced performance and to add an egress window, escape window, into each habitable attic room, bedrooms but not bathrooms.
This allows you to keep existing doors, providing they are fitted with automatic closers.
Escape windows must have a clear opening span of at least 450mm x 450mm and be in a position where there is an acceptable escape route.
Either way, the attic conversion must be separated from the rest of the house by a fire door with an automatic closer and the structure must have 30 minutes fire resistance (a stud wall with 15mm plasterboard on both faces is sufficient) and a hard-wired (connected to the mains) smoke detector.
Ventilation New attic rooms need to have both an openable window to give 'rapid ventilation' (minimum 1/20 th of the floor area) and background ventilation via a whole-house ventilation system, trickle vents or similar air vents.
Any bathrooms must also be fitted with mechanical extraction.
The roof structure between the new insulated sloping ceilings and the roofing felt also needs to be ventilated to prevent the build up of potentially damaging moisture.
This is usually achieved by leaving at least a 50mm air gap between the insulation and the underside of the roofing felt.
This void must be ventilated at eaves and ridge.
Where the rafters are not deep enough for 55-60mm of insulation plus a 50mm air gap, it may be necessary to add battens or to use an ultra-thin foil-type insulation product combined with rigid insulation board.
Where the roof is being rebuilt or the roof covering lifted and relayed, an alternative to adding vents is to use a breathable roofing membrane.
This can eliminate the need to leave the 50mm ventilation space and add vents.
Thermal Insulation Loft rooms have to be insulated to a high standard to meet the current requirements for conservation of fuel and power.
It is generally accepted that superior insulation products have to be used, such as rigid urethane foam boards with a foil facing, or even better, rigid phenolic foam boards with a foil facing.
To achieve the minimum requirement of a U-value of 0.
3 W/m2K, it is necessary to add around 55-60mm of insulation between the rafters (leaving a 50mm clear void between the top of the insulation and underside of the roof felt) plus a further 25mm of insulation underneath the rafters covered by plasterboard.
This minimum thermal performance can be significantly improved by adding more insulation.
Acoustic Insulation The roof and external walls must meet a minimum standard of acoustic insulation.
It is also a good idea to try to reduce the sound between the new attic rooms and the floor below.
Placing mineral wool insulation in the floor structure will reduce airborne sound transfer.
Laying acoustic matting over the floor structure usually made from recycled rubber, before laying carpets or a floating floor will reduce impact sound transfer.
Staircase Access A residential attic conversion must have a permanent access staircase.
Ideally this will be a conventional staircase, however, in certain circumstances a space saver staircase, or a permanent ladder can be acceptable.
The circulation space required to reach and house a new staircase will ideally be taken from an existing hallway.
Where possible the new flight can repeat the main flight from the ground floor.
The minimum practical width for an access corridor is 900mm.
Where the space needs to be taken from existing rooms the space that is lost needs to be weighed up against the space that is lost needs to be weighed up against the space gained in the attic.
Careful consideration needs to be given to which room can afford to lose the space for the access, making sure that each room retains good proportions and is a practical, usable space.
Conventional Staircase A conventional staircase leading to an attic must meet building regulations and have treads (the horizontal part of each step) and risers (the vertical part between treads) of no more than 220mm and a maximum pitch of 42 degrees.
There is no minimum width for a staircase defined by the building regulations, but a width of 600-850mm is the practical minimum.
There should be a minimum of 2m headroom above the stairs, however, in situations where the stairs are running beneath a sloping roof this can be reduced to 1.
9m at the centre point of the flight, with a minimum of 1.
8m at the edge.
There must be a landing at the top and bottom of the stairs of the same width and depth as the width of the flight.
Doors can be fitted at the edges of the top landing, but must swing away from it (into the attic rooms).
Doors around the bottom landing can swing either way providing at least 400mm of clear space is left at the bottom of the flight.
Space-saver Staircases A space saver staircase with alternating trends is acceptable where there is only one attic room (including a bedroom with an en-suite bathroom, providing there is another bathroom elsewhere in the house).
Loft Ladders A fixed loft ladder with handrails is acceptable providing there is only a single attic room and a staircase cannot be added without altering other bedrooms.
Windows There are three options for bringing light and rapid ventilation into the roof space: gable windows, dormer windows and rooflights.
Conventional windows can be added into gable end walls, if planning permission is required, the main issues will be whether or not the window creates privacy problems due to the proximity of neighbouring properties, Creating a new window opening and fitting a double glazed window will cost around £700-800.
Dormer windows stand out from the line of the roof slope.
As they increase the volume of the house they constitute an extension and therefore require planning permission.
A dormer window will cost from £7-800 upwards depending on size, including a double glazed window unit.
A dormer window can be used to create additional headroom in the loft, often providing a solution to the shortage of headroom above staircases, a landing area or for bathrooms.
Rooflights are windows that are fitted in line with the pitch (slope) of the roof.
Rooflights can usually be inserted without requiring planning permission.
A rooflight can add around 200mm of headroom, sufficient in some instances to overcome the shortage of headroom above a staircase, or for a landing area.
A standard rooflight, fitted, costs from £4-500 upwards depending on size.
Special Rooflights Rooflights are available in large sizes and several can be combined to rooflights form feature windows.
Models are available that open up to comply with regulations for fire escape windows, and others open up to form a balcony.
Where conventional rooflights are not acceptable, for instance on listed buildings and in conservation areas, conservation rooflights may be acceptable.
These are designed to mimic traditional cast iron rooflights that sit flush with the roofline.
In addition, lightpipes channel light through mirrored ducting into rooms where other forms of natural lighting may be unsatisfactory.
Heating, Plumbing and Electrics Providing the boiler has sufficient output, new radiators for the attic rooms can usually be added to the existing central heating system.
Any water storage tanks in the existing loft will have to be moved or replaced to make room for the conversion.
Where there is no space to move the tanks elsewhere in the loft (gravity-fed systems have to be higher than the highest outlet or radiator in order to work) an alternative is to upgrade to a modern pressurised (unvented) plumbing system that does not require header tanks.
The choice is between a combination boiler which will fire the central heating plus provide hot water on demand, or a system boiler to fire the central heating, plus a pressurised hot water storage cylinder which can be located anywhere in the house.
New power points and lighting circuits can usually be added to existing circuits or on new circuits added to the existing consumer board.
Domestic wiring is now covered by the building regulations and if the existing wiring needs upgrading, this work will have to be done at the same time as the new wiring for the loft conversion.
Exclusions Mezzanine attic rooms, an open gallery covering an area of less than 50% of the floor below, have more relaxed fire regulations providing the space is non-habitable room.
Loft conversions above bungalows are also excluded from most of the regulations, although the staircase must still lead directly to an external door.
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