Resource · Plain-English Guide

What Is Tempered Laminated Glass?

Quick answer: Tempered laminated glass combines tempered safety glass (heat-treated for strength and safe break pattern) with laminated construction (two glass layers bonded to an interlayer). The result: maximum safety + impact resistance. Required in Florida HVHZ assemblies, glass railings, overhead glazing, and security applications.

Why combine tempered AND laminated

Tempered glass alone breaks safely (small granular pieces) but doesn't stay in place when broken. Laminated glass stays in place when broken but isn't strong enough on its own. Tempered laminated combines both: 4-5x annealed strength PLUS the laminated interlayer holding the assembly together. The standard for Florida HVHZ commercial work.

Standard tempered laminated assembly

Typical Florida HVHZ tempered laminated lite: 1/4" tempered glass + .090 PVB interlayer + 1/4" tempered glass = 0.59" nominal thickness. For higher performance: 1/4" tempered + .090 SGP + 1/4" tempered (SGP is 100x stiffer than PVB, used on the most demanding applications).

Where Florida code requires tempered laminated

HVHZ-rated openings (Miami-Dade, Broward, parts of Palm Beach east of Military Trail) require laminated assemblies. Many HVHZ NOAs specifically require tempered laminated. Glass railings require structural laminated glass (typically tempered laminated). Overhead glazing per IBC 2407 requires laminated.

Cost comparison

Tempered alone: $25-$45/SF on 1/4" thickness. Laminated tempered: $55-$95/SF on 1/2" laminated thickness. Insulated tempered laminated impact (the full HVHZ commercial standard): $80-$140/SF as a complete IGU.

HVHZ approval considerations

Each tempered laminated assembly is tested as a unit and approved via Miami-Dade NOA. You cannot substitute one manufacturer's tempered glass with another manufacturer's laminated interlayer and expect the NOA to apply. The full assembly (specific glass + specific interlayer + specific framing) must match the tested combination.

Frequently asked

What is tempered laminated glass?

Tempered laminated glass combines tempered safety glass (heat-treated for strength) with laminated construction (two glass layers bonded to an interlayer). Used in Florida HVHZ assemblies, glass railings, overhead glazing, and security applications.

Why is tempered laminated used in HVHZ?

Florida HVHZ assemblies need both impact resistance (laminated holds the assembly together) AND safety break pattern (tempered breaks into safe granular pieces). Tempered laminated provides both in one product.

How thick is tempered laminated glass?

Standard 1/4" tempered + .090 interlayer + 1/4" tempered = 0.59" nominal thickness. Heavier applications use 3/8" + .090 + 3/8" = 0.84". The interlayer can be PVB (standard) or SGP (premium, 100x stiffer).

Is tempered laminated more expensive than just tempered?

Yes — tempered laminated typically costs 2-3x more than equivalent tempered alone. The premium covers the additional glass lite, the interlayer material, and the laminated fabrication labor.

Can tempered laminated be cut or drilled?

No. Like all tempered glass, it cannot be cut or drilled after fabrication. All openings, holes, and edge profiles must be specified before tempering.

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