Question 1

When is safety glass required in doors?

Accepted Answer

Under Approved Document K (2013 incorporating 2020 amendments) Section 5 Diagram 5.1, safety glass must be used in (a) any glazing in a door where the glazing sits below 1500 mm from floor level, (b) any glazing in a side panel within 300 mm of the door edge and below 1500 mm, and (c) wall glazing within 800 mm of floor level. Door and side-panel panels use the 1500 mm rule, not the 800 mm wall rule — this is a common source of non-compliance. Safety glass means toughened to BS EN 12150 or laminated to BS EN 14449, tested to BS EN 12600 Class B or C (replacing the older BS 6206 Class B / C classification).

Question 2

What is the difference between toughened and laminated glass in doors?

Accepted Answer

Toughened glass is 4-5 times stronger than annealed glass and breaks into small, relatively harmless fragments. Laminated glass has a PVB interlayer that holds fragments together when broken, providing better security and sound insulation. For front doors, laminated is preferred for security. For internal doors, toughened is common due to lower cost. BS 6262-4 gives guidance on glass selection.

Question 3

How do I measure glass for a door panel?

Accepted Answer

Measure the aperture (rebate to rebate) and deduct the beading overlap on each side, typically 8-12mm per side. For a 500mm aperture with 10mm beading overlap, the glass size would be 480mm. Always measure at three points and use the smallest dimension. Allow 2-3mm clearance for thermal expansion in dark-coloured doors.

Question 4

What glass thickness do I need for door panels?

Accepted Answer

For small panels (under 0.5m2), 4mm toughened is adequate. Medium panels (0.5-1.5m2) need 6mm toughened or 6.4mm laminated. Large panels (1.5-2.5m2) require 8mm toughened or 8.8mm laminated. Full-height glass doors typically use 10mm toughened or 11.5mm laminated. These are minimums; always check with your glass supplier for specific loadings.

Question 5

Can I use decorative glass in a door?

Accepted Answer

Yes, but it must still be safety glass in critical locations. Decorative obscure glass is available in toughened form to comply with BS 6206. Popular patterns include Cotswold, Flemish, Autumn, and Contora. For composite doors, decorative cassettes with internal Georgian bars and obscure outer pane are common. Ensure any decorative glass meets the relevant safety standard for its location.

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