Means of warning and escape

Mains-wired smoke detectors are needed in the hall, landing and stairs of all storeys.

• There should be at least one detector on each storey, and the detectors interlinked (so that a detection of any one, triggers all of them),
•  Each must be mounted within 7.5m of the door to any habitable room, and at least 300mm from walls and light fittings, and
•  They must be either wired to a separate circuit from the consumer unit, and have a battery back up.

The existing stairway (i.e., the hall at ground floor, the stairs from ground to the first floor and the first floor landing) at ground and first floor level should be enclosed within 30-minute fire resisting walls. The stairway should not be open to any other room such as a lounge, kitchen, etc.

Any glazing onto the staircase in the house will need to be upgraded to give a half hour's fire resistance.

The stairway should open either:

• directly to a final exit or
• to a space from which two escape routes are provided, each leading to final exits and separated from each other by fire resisting construction and fire doors.

All existing doors to habitable rooms at ground and first floors opening onto the hall or landing should be replaced with FD20 fire doors, and any new doors to the hall and landing need to be fire resisting as well. There is no longer a requirement that these doors are made self closing.

If you wish to keep existing doors in place because of the architectural or historical merit, these will need to be upgraded to give 30 minutes fire resistance. This can be achieved by the application of special fire resisting paints, papers or varnishes (intumescents). There are specialist companies who provide the materials and assessment service for such upgrades. Building Control will need a detailed specification to ensure that the doors will give provide the necessary fire resistance.

A new stair within an existing stairway enclosure should be separated from any new rooms by an FD20 fire door and fire resisting walls. Alternatively, the new stair may be separated from the existing storey by a fire door and fire resisting construction.

As the staircase is now protected by a fire resisting enclosure, including the doors, there is no longer a requirement for an escape window to be provided in the converted loft (new 2nd floor).

Fire resistance

The new floor and any structure supporting it must have a fire resistance of 30 minutes from underneath. This should extend to the inside face of the external walls.

The fire resistance of a floor is dependent on the ceiling beneath, the size and spacing of joists, and the boards over.

• The existing lath and plaster ceiling below may provide the required fire resistance, provided that it is in good condition and firmly attached to the laths. If the ceiling is plasterboarded then 12.5mm thick boards are required to give 30 minutes fire resistance. You may have to provide an additional skim coat or additional plasterboard to the ceiling.
• Joists to be at a maximum of 600mm centres, and at least 38mm wide (if the floor falls outside these limits you should consult Building Control),
• Floor boarding over to be tongue and grooved, or plain edged boards overlaid with hardboard (to restrict smoke and hot gases that might penetrate the ceiling).

The first floor over any habitable rooms under the landing should also have 30 minutes fire resistance. If the existing floor is plain edged boards, or badly fitting tongue and grooved boards, this should be overlaid with hardboard.

The separating walls between dwellings should have at least 60 minutes fire resistance. Some older properties do not have separating walls within the roof space, or may have holes or gaps in them. These will need to be sealed up to the underside of the roof covering. You will also need to be careful of any new structural elements supported on this wall, or passing through it (if beams, floor joists or purlins pass through the wall, they can provide a route for smoke, fire and sound to spread from one house to another). Please contact Building Control for advice.