Does laminated glass stop UV?

Laminated glass reduces ultraviolet (UV) transmission significantly, but it does not block 100% of UV. For roof lights, the practical question is whether the standard laminated inner pane provides enough protection for furnishings below — and what it does not do.

How UV passes through glazing

Sunlight contains:

• UV-A (roughly 315–400 nm) — passes through most standard glass; contributes to fading.
• UV-B (roughly 280–315 nm) — more harmful to skin and materials; largely absorbed by glass.
• Visible light (roughly 400–700 nm) — what we see.
• Infrared — heat; affected by low-E coatings, not UV questions.

Ordinary monolithic toughened glass absorbs some UV but transmits enough UV-A to cause gradual fading of fabrics, timber floors and artwork over years of direct exposure.

What the PVB interlayer does

Standard PVB interlayers in laminated safety glass under BS EN 14449 absorb most ultraviolet below approximately 380 nm. In practice this means:

• The majority of UV-B is blocked.
• A large proportion of UV-A is blocked — often quoted in manufacturer data as 99% UV protection, though definitions vary by test method.

The laminated inner pane of a roof light therefore offers meaningfully better fade protection than a non-laminated build, as a side benefit of the safety interlayer.

What laminated glass does not do

It is not a sunscreen for people. Some UV-A still transmits. Occupants under a roof light are not in “full shade” from a UV perspective, though exposure is reduced compared with open sky.

It does not control heat or glare. UV reduction does not lower solar gain (g-value) or room brightness. A south-facing laminated roof light can still overheat a room — address that with solar-control coatings, ventilation or shading for Part O compliance.

It is not absolute fade prevention. High-value art, museum pieces or exotic timbers may need dedicated UV-filtering film or external shading beyond standard PVB.

Laminated vs toughened-only overhead

Factor

Toughened monolithic inner

Laminated inner (PVB)

Post-breakage retention

No

Yes

UV fade reduction

Modest

Substantial

Safety classification

Toughened (BS EN 12150)

Laminated safety (BS EN 14449)

Typical roof light use

Uncommon for inner pane

Standard for inner pane

For overhead glazing in dwellings, the safety case for lamination is the primary driver. UV filtering is a useful secondary benefit.

Enhanced UV options

If fade control is critical:

• Specialised PVB or film interlayers with enhanced UV absorption.
• Applied window film on the inner face (confirm compatibility with the sealed unit warranty).
• External shading — most effective for both UV and heat.

Discuss requirements with your roof light manufacturer before assuming standard laminated glass meets museum-grade UV limits.

Measuring UV performance

Manufacturers sometimes quote UV transmittance or UV rejection percentages. Test methods and wavelength ranges differ, so compare like with like. For most residential roof lights, standard PVB laminated glass offers a practical balance of safety retention under BS EN 14449 and fade protection without premium interlayers. Where documentation is required — retail displays, galleries, heritage interiors — request declared optical data from the glass processor.

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.