BS 6262 glazing code of practice

BS 6262 (Glazing for buildings — Code of practice) is the principal UK document bridging product standards and safe glazing practice in buildings. It tells designers, fabricators and installers how to select glass types, identify critical locations, determine minimum impact classifications and address environmental actions — wind, snow, thermal stress and differential movement. Approved Document K explicitly references BS 6262 as a route to satisfying Building Regulations requirements for protection from impact and falling glass.

For professionals specifying roof lights, BS 6262 is the document that explains why a laminated inner pane is required overhead and how to coordinate glass selection with frame design, edge cover and load resistance. This advanced reference summarises the structure and key clauses relevant to overhead glazing.

Structure of BS 6262

The code is organised to follow the glazing specification process:

• Materials — glass types (annealed, heat-strengthened, toughened, laminated), plastics and combinations. Cross-references to BS EN 12150 (toughened), BS EN 14449 (laminated) and other product standards.
• Critical locations — diagrams and height bands defining where safety glass is mandatory. Overhead glazing is a distinct category.
• Impact safety — mapping of locations to BS EN 12600 pendulum test classes.
• Design considerations — support width, edge cover, clearance to building materials, thermal stress, wind and snow load interaction with the structural engineer’s calculations.
• Special applications — sloping glazing, walk-on glazing, balustrades and glazing in barriers — each with additional rules.

Compliance with the code of practice does not itself constitute compliance with building regulations, but it is the accepted means of demonstrating that glazing safety requirements are met.

Critical locations and impact classes

BS 6262’s critical location diagrams are familiar to architects from Approved Document K. For overhead glazing — roof lights, glazed roofs, sloping roof glazing — the standard requires glazing that does not fall from the frame if broken. This mandates laminated safety glass (or an approved alternative retaining system) for the inner pane, not toughened glass alone.

Impact classification under BS EN 12600 uses a pendulum test producing classes such as 1B1 (highest) through 3B3. BS 6262 assigns minimum classes to each critical location. Overhead retention takes precedence over impact class for the inner leaf — a pane that survives impact but falls when broken is unacceptable.

For the outer pane of a roof light, wind and snow loads often govern thickness rather than impact class. The outer leaf is typically toughened or heat-strengthened, sized by the manufacturer or structural engineer for the project design loads per BS EN 1991 actions on structures.

Edge cover, support and clearance

BS 6262 specifies minimum edge cover — the depth to which glass is recessed in the frame or bead — to prevent dislodgement under load and temperature movement. For insulating glass units in roof lights, the standard also addresses support of the unit on setting blocks, location of spacer bars and protection of sealants from UV where applicable.

Clearance between glass and framing must accommodate thermal expansion and building movement without inducing stress concentrations. Sloping installations — common in pitched roof lights — require particular attention to self-weight component and sliding tendency; units must be supported at the lower edge per manufacturer instructions, which should align with BS 6262 principles.

Environmental actions on roof glazing

Roof lights experience positive and negative wind pressure, snow accumulation on horizontal and low-pitch units, and thermal stress from solar radiation and night cooling. BS 6262 directs the specifier to coordinate with the structural engineer for load derivation and with the glass supplier for stress limits.

Deflection limits and pane aspect ratios affect optical distortion and stress. Large spans may require thicker panes, heat-strengthened rather than fully toughened outer leaves (to reduce roller-wave distortion) or stiffened frame profiles.

Sloping and overhead glazing sections

Dedicated clauses cover overhead and sloping glazing distinguishing them from vertical windows. Fall-through protection, retention, cleaning access and maintenance anchors (where used) fall within the scope. Walk-on roof lights cross into structural floor glazing territory with imposed load requirements beyond standard skylight clauses — multiple laminated toughened panes and a structural assessment are mandatory.

Relationship with CE / UKCA marking

Glazing products placed on the market under BS EN 14351-1 (windows and doors) or BS EN 12150 / BS EN 14449 (glass products) carry declared performance. BS 6262 is the application layer — it tells you which declared performances are needed in which location. A roof light marketed as a complete unit should have test data for the assembly; site-built combinations of generic glass in a site-fabricated frame require case-by-case justification.

Documentation for building control

A BS 6262-aligned submission for roof glazing typically includes:

• Glass type and thickness for each leaf.
• BS EN 12600 impact classification where applicable.
• Evidence of overhead retention (laminated inner pane declaration).
• Wind and snow load assumptions and pane thickness calculation.
• Frame edge cover dimensions per manufacturer detailing.
• Fixing and kerb specification maintaining structural support.

Using BS 6262 in practice

Treat BS 6262 as the checklist behind your glazing specification. For roof lights, the non-negotiable overhead rule — laminated inner pane for retention — is the clause most often cited by building control. Pair it with load-rated outer panes, correct edge cover in the frame and installation per the manufacturer’s tested detail.

Manufacturers of made-to-order roof lights engineer the glass build-up for each opening size against these principles. Provide your project’s load and regulatory context when requesting a quotation for custom roof lights.

Vant Glass manufactures premium roof lights and glazing in Aintree, Liverpool — made in Britain, 20-year guarantee, free UK mainland delivery. Explore all products or call 03330 902 592.