What Is Laminated Glass?

 

Laminated glass consists of two or more sheets of glass bonded around a transparent interlayer.

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If the pane is struck and breaks, the interlayer helps hold the fragments together. The glass may crack across its surface, but it is less likely to collapse immediately or leave a completely open gap.

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This behaviour distinguishes laminated glazing from ordinary annealed glass and toughened glass.

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Its benefits can include:

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• Reduced risk of loose glass fragments

• Greater resistance to penetration

• Improved security after breakage

• Better acoustic performance

• Some protection against ultraviolet light

• Greater protection in overhead or critical glazing locations

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Different combinations of glass and interlayers can be manufactured for different applications.

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What Is Laminated Safety Glass?

 

Laminated safety glass is designed to reduce the risk of injury when the glass is broken.

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The interlayer retains much of the shattered glass, helping to prevent large pieces from falling freely into the surrounding area. It can also continue to provide a temporary barrier until the pane is made safe and replaced.

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Laminated safety glass may be considered for:

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• Low-level windows

• Glazed entrance doors

• Side panels beside doors

• Sliding and bifold doors

• Rooflights

• Internal glazed screens

• Balustrades and guarding

• Windows above occupied areas

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The required glass thickness and classification will depend on the size, position and purpose of the glazing.

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Laminated Glass Versus Toughened Glass

 

Toughened and laminated glass are both forms of safety glazing, but they behave differently.

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Toughened glass

Toughened glass is heat-treated to increase its strength. When it breaks, it normally fragments into many relatively small pieces rather than large, sharp shards.

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This reduces the risk of serious cutting injuries. However, once broken, the pane usually falls away and leaves the opening exposed.

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Laminated glass

Laminated glass may crack under impact, but the interlayer helps keep the fragments in position.

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This makes it particularly useful where the glass should continue to form a barrier after it has been damaged.

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Which should you choose?

Toughened glass may be suitable where resistance to accidental impact and safe breakage are the main priorities.

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Laminated glass may be preferred where the glass also needs to:

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• Delay forced entry

• Remain in the frame after breakage

• Protect against falling

• Reduce outside noise

• Retain fragments in overhead glazing

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The correct choice should be based on the application rather than assuming one product is always better.

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Toughened Laminated Glass

 

Toughened laminated glass combines layers of toughened glass with one or more bonding interlayers.

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This can provide greater strength before breakage while retaining the benefits of laminated construction after impact. If one or more layers break, the interlayer helps hold the glass together.

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Toughened laminated glazing may be used for specialist applications such as:

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• Large glazed panels

• Structural glazing

• Roof glazing

• Glazed balustrades

• Canopies

• Floors and walk-on glass

• High-level or overhead glazing

• Large doors and screens

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The specification must be designed for its particular structural and safety role. It should not be selected solely because it sounds stronger than standard glass.

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Toughened and Laminated Glass in Double Glazing

 

Both toughened and laminated glass can be incorporated into sealed double glazed units.

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A unit might include:

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• Toughened glass on one side

• Laminated glass on the other

• A laminated outer pane for security

• A laminated inner pane for safety

• Acoustic laminated glass for noise reduction

• Low-emissivity glass for thermal performance

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This allows one window to provide several different functions, including insulation, safety, security and acoustic control.

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The installer should clearly identify which pane contains the laminated glass and why that arrangement has been selected.

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Laminated Glass for Home Security

 

Laminated glazing can make it more difficult to create an immediate opening through a window or glazed door.

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Although the glass may crack, the interlayer continues to hold the damaged pane together. Repeated force may be needed before an opening can be formed.

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It can therefore be particularly useful for:

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• Ground-floor windows

• Rear and side windows hidden from view

• Glazing beside entrance doors

• Patio and bifold doors

• Basement windows

• Garage and utility-room windows

• Properties in isolated locations

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Security depends on the complete window or door. Laminated glass should be combined with a strong frame, secure glazing retention and an appropriate locking system.

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Acoustic Laminated Glazing

 

Laminated glazing can also improve sound insulation.

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Acoustic laminated glass uses a specialist interlayer designed to reduce vibration through the pane. It may be included within a double glazed unit for homes affected by:

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• Road traffic

• Railways

• Aircraft

• Schools and playgrounds

• Night-time street activity

• Nearby commercial premises

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Effective sound reduction also depends on glass thickness, the space between panes, window seals, ventilation and installation quality.

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Laminated glass alone will not provide the expected improvement if sound continues to enter through gaps around the frame.

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UV Protection and Furnishings

 

The interlayer within laminated glass can filter a significant proportion of ultraviolet radiation.

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This may help reduce fading to:

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• Curtains

• Carpets

• Timber flooring

• Furniture

• Artwork

• Fabrics and internal finishes

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Laminated glazing cannot prevent every form of fading because heat and visible light can also affect materials. However, it may provide useful additional protection in rooms receiving strong sunlight.

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Can Laminated Glass Be Fitted to Existing Windows?

 

It may be possible to replace an existing pane or sealed unit with laminated glass while retaining the current frame.

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Before carrying out the upgrade, the installer should check:

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• The frame’s condition

• Available glazing depth

• Glass thickness

• Glazing bead compatibility

• The additional weight

• Hinge and hardware capacity

• The size of opening sections

• How the glass is retained

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Laminated glass can be heavier than the glass it replaces. Larger opening windows and doors may require stronger hinges, rollers or supporting hardware.

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Where the existing frame is weak or damaged, complete replacement may provide a more suitable solution.

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Building Regulations and Safety Glazing

 

Safety glazing is required in certain locations where there is a greater risk of accidental collision or injury.

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These can include low-level windows, glazing within doors and glazing positioned close to doors. Other requirements may apply to guarding, roof glazing and protection from falling.

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Both toughened and laminated products can meet safety-glazing requirements when correctly classified and installed.

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The installer should identify all critical glazing locations and confirm the appropriate glass specification before manufacturing begins.

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Laminated Glass in Listed Buildings

 

Laminated glazing may sometimes be useful in listed buildings and conservation areas, particularly where improved security, safety or acoustic performance is required.

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However, thicker glass and modern reflections can alter the appearance of traditional windows. Listed building consent or planning permission may be required where historic glass or frames are being changed.

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Possible alternatives include:

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• Repairing the original windows

• Installing carefully selected replacement glass

• Adding internal secondary glazing

• Using slim-profile laminated products

• Retaining historic glass on visible elevations

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The planning position should be established before original windows or glass are removed.

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Choosing the Correct Laminated Glazing

 

The phrase “laminated glass” does not describe one standard level of performance.

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Before ordering, confirm:

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• The glass thickness

• Number of laminated layers

• Interlayer type and thickness

• Safety classification

• Security-test classification, where required

• Acoustic performance

• Whether the glass is also toughened

• Its position within the double glazed unit

• Compatibility with the proposed frame

• The complete weight of the glazing

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The quotation should identify the exact glass specification rather than simply describing the unit as safety or security glass.

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Find Trusted Laminated Glass Installers

 

Correct specification and installation are essential when laminated glazing is being used for safety, security, acoustic control or protection from falling.

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APN Double Glazing can connect homeowners with experienced local installers for laminated safety glass, toughened laminated glass, acoustic glazing and replacement double glazed units.

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Get in touch for expert advice and a free, no-obligation quote for laminated glazing in your windows and doors.

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