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Summary advice for Building Regulations

Various Building Regulations apply to replacement windows and doors. Please read the FENSA guidance booklet.

How do I get a FENSA certificate?
FENSA certificates certify the actual installation. Your installer should be able to issue a FENSA certificate. If not, or you are installing yourself, your local Building Control can certify your installation. More information:

FENSA safety glazing example

Glazing Safety - summary Document Part K4 & N1

Toughened or laminated glass is required in critical locations which are subject to accidental human impact, as a minimum:

  • Glazing at low levels: if the bottom of the glazing is within 800mm of the floor level.
  • Glazing in doors: any glass in doors that starts lower than 1,500mm from the floor.
  • Glazing adjacent to doors: windows/side panels starting within 300mm of the edge of a door and also starting within 1,500mm from the floor.

The example diagram to the right shows glass panes where toughened or laminated safety glass is required, marked with:

Fire Escape - summary of Document Part B

Ground floor windows: Fire escape windows are required on the ground floor in any habitable room (not a kitchen or bathroom) which does not open into a hall that leads directly to an exit door.

Upper floor windows: On upper floors up to 4.5 meters from ground level, all habitable rooms (not kitchens or bathrooms) must be fitted with fire escape windows, unless the room has direct access to a protected stairway.

A fire escape window's openable area should be less than 1100mm from the floor and should open without obstruction to at least 0.33m² and at least 450mm high or 450mm wide. If one of the dimensions is at the 450mm minimum then the other dimension will need to be at least 734mm to achieve 0.33m2.

Windows fitted with our Fire Escape and Easy Clean hinges comply with the above regulations as long as the openings are sufficient; we recommend 600mm pane width to achieve the clear 450mm width.

Ventilation - summary of Document Part F

All rooms must be adequately ventilated to avoid the accumulation of contaminants and/or condensation. Good indoor air quality is important for health and also has many benefits to the building itself. All of our windows have 2 stage locking handles to assist with ventilation.

Background ventilation for new homes and extensions: All windows being installed into a new build home or extension should provide background ventilation in the form of trickle ventilators.

Background ventilation for replacement windows: If the original windows have trickle vents then the new windows must have them too. If however the outgoing windows do not have trickle vents fitted then two stage locking handles are acceptable (fitted to all of our windows as standard). It is important that the new windows do not have a worse level of compliance than the outgoing windows.
Typically, trickle vents are positioned at least 1.7 metres above finished floor level to avoid discomfort due to draughts.

Purge Ventilation: For the purpose of purge ventilation the total openable area should be at least the same as the outgoing window. For new build homes and extensions, the openable area has to be at least 1/20th of the floor area of each room.

document part M opening width

Access - summary of Document Part M1

For replacement doors, the new door should be the same or more accessible than the previous door. The height of the door threshold- cill should not be made worse.

For new build homes, external doors should have a threshold-cill no higher than 35mm, except in areas of high weather exposure, in which case up to 50mm is acceptable. If that is not possible due to design considerations, a maximum gap of 35mm measured from the underside of the door leaf to the finished internal floor level would be acceptable.

The opening width of principal doors, should be a clear minimum of 775mm, from the edge of the frame to the face of the door leaf open at 090 degrees.

Security for new build homes and extensions - summary of Document Part Q

    Accessible (roughly somewhere a burglar could possibly reach) windows and doors must:
  • Comply with British Standards PAS 24:2012 (also usually included in Secured By Design).
  • Main entrance doors must have a spyhole or clear glass, and a door chain, and any letter plates need to comply with TS008.
  • Windows that open without key locking must have laminated glass. (Our windows have key locks on all openers).
  • Door glazing and glazing near doors (side panels or windows) must be laminated.

Disclaimer: All information detailed above is simply a brief summary of current building regulations and is by no means complete. Please refer to Building Regulation documents and consult your local building inspectors. No responsibility will be entertained for any compliance issues arising from relying on the information above.
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