Impact glass is the most critical decision in your window replacement project. The wrong glass type means failed inspections, voided warranties, and a home that cannot withstand 170 MPH winds. This guide walks you through every variable that determines which glass your Broward County property actually needs.
Follow the flowchart to determine the right glass type for your specific situation. Each decision point narrows down your options based on Broward County code requirements.
Understanding why Broward County requires laminated glass, not tempered, for opening protection in the Wind-Borne Debris Region.
Two or more glass plies permanently bonded with a plastic interlayer (PVB or SGP). When struck by hurricane debris, the glass cracks but the interlayer holds fragments in place, maintaining a weather-tight barrier. This "post-breakage integrity" is what makes laminated glass code-compliant for impact protection in Broward County.
Single pane heated to 1,200F then rapidly cooled, creating surface compression that makes it 4-5 times stronger than annealed glass. However, when tempered glass fails, it shatters into thousands of small cubes with no remaining barrier against wind and rain. Tempered glass alone does not qualify as opening protection in Broward County's WBDR.
A common misconception among Broward County homeowners is that "impact glass" and "tempered glass" are interchangeable terms. They are fundamentally different products. Tempered glass is a strengthening treatment applied to a single pane. Laminated impact glass is a multi-layer assembly specifically engineered to withstand debris impact and maintain the building envelope after breakage.
The Florida Building Code 2023, Section 1626.1, requires all glazed openings within the Wind-Borne Debris Region to be protected by either impact-resistant glazing (laminated glass systems tested to ASTM E1886/E1996 or TAS 201/202/203) or approved shutter systems. Tempered glass used as an outer ply in a laminated assembly does add strength, but tempered glass by itself does not constitute impact protection. Broward County building inspectors specifically verify the Florida Product Approval number on every window label to confirm impact compliance.
The interlayer is the invisible backbone of impact glass. It determines how well your window performs after the outer glass ply breaks during a hurricane.
PVB has been the workhorse interlayer for impact-resistant glazing for over three decades. At 0.060 inches thick (1.52mm), a single PVB layer provides adequate post-breakage retention for most residential windows in Broward County. It bonds reliably to glass, offers excellent optical clarity, and blocks 99% of UV radiation. For standard-sized windows on single-story homes in Exposure B zones, PVB delivers proven hurricane performance at a reasonable price point.
SGP is an ionoplast interlayer that outperforms PVB in every mechanical property. With 5 times the tear strength and 100 times the rigidity of PVB, SGP keeps broken glass panels structurally engaged far longer during sustained hurricane winds. This matters most in Broward County for large openings that experience high cyclical loading, upper-floor windows in coastal exposure, and corner-zone glazing where suction pressures can exceed -90 psf.
For the majority of Broward County single-story residential windows under 25 square feet with DP requirements below +60/-75 psf, a quality PVB-based laminated glass system provides reliable code-compliant protection. SGP becomes the clearly superior choice when your wind load calculation demands DP ratings above +65/-80, when window sizes exceed 40 square feet, or when you are above the second floor in Exposure C or D. The 15-25% cost premium for SGP is well justified in those higher-demand applications because the interlayer carries a disproportionate share of the post-breakage load.
Thicker glass resists higher wind pressures across larger spans. Here are the most common residential configurations for Broward County homes.
Glass thickness alone does not determine wind resistance. The combination of glass ply thickness, interlayer type and thickness, glass treatment (annealed, heat-strengthened, or tempered), and the frame system all contribute to the final DP rating. A 7/16" laminated glass unit with SGP interlayer in a reinforced aluminum frame can achieve higher DP ratings than a 9/16" unit with standard PVB in a basic vinyl frame. This is why selecting your window system based on the required DP rating from your wind load calculation is more accurate than selecting glass thickness in isolation.
In Broward County, the most frequently installed residential configuration is the 7/16" laminated unit with 0.060" PVB, which handles the DP requirements for most single-story suburban homes in Exposure B. Properties east of I-95 approaching the coastline, or two-story homes with larger window openings, commonly step up to 9/16" laminated glass to meet the higher DP demands of Exposure C.
Design Pressure (DP) is measured in pounds per square foot (psf) and represents the maximum wind pressure a window can handle. Positive (+) is inward push; negative (-) is outward suction.
Single-story home in Exposure B, windows in the field-of-wall (not corners), less than 20 sq ft per opening. Covers most suburban Fort Lauderdale neighborhoods west of US-1.
Two-story home or single-story in Exposure C, corner zone windows, sliding glass doors. Common in Pembroke Pines, Coral Springs, and Plantation near open areas.
Multi-story home within 1 mile of the coast, Exposure C or D, large openings, upper floors. Typical for Pompano Beach, Deerfield Beach, and Hallandale Beach oceanfront properties.
Top-floor corner windows on 3+ story coastal buildings, large glass walls facing the ocean in Exposure D. These extreme ratings require SGP interlayer, heavy-duty frames, and engineered anchoring. Rare for single-family but common in waterfront townhomes.
The negative (suction) value on a DP rating is almost always the controlling factor for impact glass selection in Broward County. Wind flowing around a building creates suction on the leeward and side walls that tries to pull windows outward. Per ASCE 7-22 Chapter 30, the component and cladding suction pressures in corner zones (Zone 5) are typically 40-60% higher than the positive pressures in the same location. This is why a window rated DP +50/-60 is not the same as one rated DP +50/-50. Always match your window selection against the highest negative pressure from your wind load calculation, which will usually be the corner zone suction value.
Every impact-rated window installed in Broward County carries a permanent certification label. Here is exactly what each field means and which numbers matter most for your permit.
This is the Florida Product Approval number. Broward County inspectors will look up this number to verify the window is approved for use in the Wind-Borne Debris Region. You can verify it yourself at the Florida Building Code product approval database. If the number is missing or expired, the window will fail inspection.
The DP values show maximum positive (inward) and negative (outward/suction) pressure the window withstands. Your wind load calculation determines the minimum DP required. The label DP must meet or exceed your calculated requirement. A window rated DP +55/-65 is acceptable for an opening requiring DP +50/-60, but not one requiring DP +60/-75.
"Large Missile" means the window passed the 9-lb 2x4 lumber impact test at 50 fps, which is required for all glazed openings in Broward County's WBDR up to 30 feet above grade. "Small Missile" only covers roofing and openings above 30 feet. Residential windows at any floor height in WBDR almost always need Large Missile rating.
The PG number equals the highest absolute DP value. A window labeled PG-65 means the greater of its positive or negative DP value is 65 psf. This is a quick reference, but always check both positive and negative values separately because they may not be symmetric. PG-65 could mean DP +55/-65 or DP +65/-50.
Both methods satisfy Florida Building Code opening protection requirements. But the right choice depends on your budget, property type, and lifestyle priorities.
While the Florida Building Code allows either impact glass or shutters for opening protection, several Broward County scenarios effectively require impact glass by default. New construction projects increasingly specify impact-rated glazing because it eliminates the need for shutter installation, deployment logistics, and the aesthetic concerns raised by HOA architectural review boards. Many planned communities and condominiums in cities like Weston, Parkland, and Southwest Ranches have covenants that prohibit visible shutter hardware, leaving impact glass as the only practical compliance path.
Additionally, the 2023 FBC energy code updates (FBC Energy Conservation, Section C402.4) create glazing performance requirements for U-factor and Solar Heat Gain Coefficient (SHGC) that are more easily met by modern insulated impact glass units than by shutter-protected non-impact windows. When you add the insurance premium reductions, the 10-15 year payback analysis often favors impact glass for homes valued above $400,000 in Broward County.
Detailed answers to the most common questions Broward County homeowners ask about impact glass selection.
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