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Understanding Building Regulations for Glazing: A Comprehensive Guide

When it comes to installing windows and doors, whether in new builds or as replacements, understanding the relevant building regulations is crucial. At Lyme Bay Bifolds, we aim to make this process as smooth as possible. Here’s a comprehensive guide to the UK building regulations for aluminium glazing.

Obtaining Certification

One of the first steps in ensuring compliance with building regulations is obtaining certification. Lyme Bay Bifolds is proud to be Assure accredited. Assure Certification operates similarly to FENSA, serving as a self-certification scheme for compliance with building regulations. Your installer should provide an Assure Certification certificate upon completion of the installation. If not, or if you're doing the installation yourself, your local Building Control can certify the work.

Fire Escape Regulations

Ground Floor Windows: In habitable rooms (excluding kitchens and bathrooms) on the ground floor, fire escape windows are required unless the room opens into a hallway leading directly to an exit door.

Upper Floor Windows: For upper floors up to 4.5 meters from ground level, all habitable rooms (excluding kitchens and bathrooms) must have fire escape windows unless the room has direct access to a protected stairway.

Specifications for Fire Escape Windows:

  • The openable area should be less than 1100mm from the floor.

  • Must open without obstruction to at least 0.33m² and be at least 450mm high or 450mm wide.

  • If one dimension is at the 450mm minimum, the other dimension should be at least 734mm to meet the 0.33m² requirement.

  • Our windows with Fire Escape and Easy Clean hinges comply with these regulations, provided the openings are sufficient; a 600mm pane width is recommended to achieve the clear 450mm width.

Ventilation Requirements

New Regulations Effective from 15th June 2022: Rooms must be properly ventilated to prevent the buildup of contaminants and condensation. Good indoor air quality is vital for health and benefits the building itself.

Minimum Equivalent Area of Trickle Vents per Room:

Room Type

Multi-Floor Dwelling

Single-Floor Dwelling

Habitable rooms & kitchens

8,000 mm²

10,000 mm²


4,000 mm²

4,000 mm²

Utility & WC/cloakrooms



Key Points:

  • If replacing a window with trickle vents, the new window should have at least the same number and mm² of vents.

  • For new windows or if the original window lacks vents, vents are required per the table above unless other ventilation methods are available.

  • If fitting the required vents is not feasible, aim for as close as possible.

  • Typically, trickle vents are positioned at least 1.7 meters above the finished floor level to avoid draught discomfort.

  • Expert advice is needed if the dwelling has only one exposed facade, 70% of openings on the same facade, or windowless rooms.

  • Open plan kitchens require at least 3 vents of the same size as other rooms.

  • Purge ventilation: Minimum opening size of all window openers and all doors to be 1/20th of the floor area of each room.

Glazing Safety Regulations

Toughened or Laminated Glass Requirements:

  • Low Levels: Glazing within 800mm of floor level.

  • Doors: Any glass in doors starting lower than 1,500mm from the floor.

  • Adjacent to Doors: Windows/side panels within 300mm of the edge of

  • a door and starting within 1,500mm from the floor.

Conservation of Fuel & Power

New Regulations Effective from 15th June 2022:

Key Points:

  • Glazed area should not exceed 25% of floor area.

  • Energy efficiency must be no worse than previous windows/doors.

  • New dwellings: Windows & doors should be sealed with air sealing tape.

Minimum Energy Efficiency Ratings:



Doors >60% Glass

Doors <60% Glass

Existing Dwelling

1.4u (B rated)


1.4u (C rated)

1.4u (B rated)

New Build - Notional





New Build - Limiting





Accessibility Standards

Replacement Doors: The new door should be as accessible or more accessible than the previous door. The height of the door threshold-cill should not be worse.

New Build Homes:

  • External doors should have a threshold-cill no higher than 35mm, except in areas of high weather exposure where up to 50mm is acceptable.

  • If design considerations prevent this, a maximum gap of 35mm from the underside of the door leaf to the finished internal floor level is acceptable.

  • Principal doors should have a clear minimum opening width of 775mm from the edge of the frame to the face of the door leaf open at 90 degrees.

Security Standards for New Builds and Extensions

Requirements for Accessible Windows and Doors:

  • Must comply with British Standards PAS 24:2012 (often included in Secured By Design).

  • Main entrance doors must have a spyhole or clear glass, a door chain, and letter plates complying 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 must be laminated.


This is a brief and incomplete summary of current Building Regulations. Please refer to the official documents and consult your installer and local building inspectors. No responsibility will be accepted for any compliance issues.

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