Custom Shape Impact Windows Miami: Arches, Triangles & Specialty Glass
Preserve your home's architectural character with hurricane-rated custom windows — arches, circles, triangles, and more, all code-compliant for the HVHZ.
Not every window opening in a Miami home is a standard rectangle. Half-round arches above front entries, triangular gable-end windows, octagonal accents in bathrooms, eyebrow arches crowning living room walls, and circular porthole designs all require windows that match their unique geometry while delivering the same hurricane-grade protection as any other opening in the building envelope. That is exactly what custom shape impact windows provide.
Custom shape impact windows use the same laminated glass technology and reinforced frame systems as standard rectangular units, but they are manufactured to fit non-standard geometric openings. They allow homeowners to preserve the architectural character of their home without compromising on storm protection, code compliance, or insurance eligibility.
This guide covers the most common custom window shapes available for Miami homes, how the manufacturing and approval process works, frame and glass options, typical costs, and what to ask your contractor before placing an order.
How Custom Shape Impact Windows Work
Custom shape impact windows are built on the same core technology as every other impact-rated window: laminated glass consisting of two or more panes bonded to a tough PVB or SGP interlayer, mounted in a reinforced frame that has been tested and certified as a complete assembly. The difference is in the geometry. Instead of cutting glass and bending or mitering frame profiles to fit a standard rectangle, the manufacturer produces components to match curves, angles, and irregular perimeters.
Common Custom Shapes
The range of available shapes is broad. Here are the most frequently specified custom geometries for South Florida residential projects:
- Half-round (arch top): A semicircular shape, typically placed above a rectangular window or impact door as a transom. This is by far the most common custom shape in the Miami market.
- Quarter-round: A quarter circle, used in pairs to flank a rectangular window or as accent pieces at the top corners of a window wall.
- Full-round (circle or oval): Complete circular or elliptical windows, often used as decorative accents in bathrooms, stairwells, or gable ends. Smaller circles are sometimes called porthole or oculus windows.
- Eyebrow arch: A shallow, elongated arc that crowns a rectangular window, creating a gentle curved top profile instead of a flat header. Popular in Mediterranean and Spanish Colonial-style homes throughout Coral Gables, Coconut Grove, and Pinecrest.
- Gothic arch: A pointed arch formed by two curves meeting at a peak, commonly seen in homes with European architectural influences.
- Triangle: Equilateral, isosceles, or right triangles, most commonly used in gable ends where the roofline creates a triangular wall space.
- Trapezoid: A four-sided shape with one pair of parallel sides, frequently used alongside triangles in gable end and vaulted ceiling applications.
- Octagon and hexagon: Multi-sided geometric shapes used as decorative accent windows. Octagons are particularly common in foyers and powder rooms.
- Pentagon: Five-sided shapes, often seen in dormer windows or where a roofline intersects a wall at an angle.
Fixed vs. Operable
The vast majority of custom shape impact windows are fixed (non-operable), meaning they do not open for ventilation. This is a practical necessity for most shapes: a half-round arch or a triangle cannot reasonably accommodate a hinge, crank, or sliding mechanism. In this sense, custom shapes function much like picture windows, providing light and views without airflow. A very small number of custom shapes, such as a trapezoidal casement, can be manufactured as operable units, but these are rare and expensive.
Because they are fixed, custom shape impact windows have no moving parts, no operator hardware, and no weatherstrip seals to wear out. This makes them extremely low-maintenance and gives them some of the best air infiltration and water penetration performance of any window type. It also means they typically achieve high Design Pressure ratings relative to their size, since there are no operable joints or hardware that could fail under load.
Manufacturing Process
Custom shape impact windows are made to order. The process begins with precise field measurements of the rough opening, often requiring a template for curved shapes. The manufacturer then cuts the laminated glass to the exact geometry, bends or miters the frame profiles to match (using specialized roll-forming equipment for curves), and assembles the unit. For curved shapes like arches and circles, the frame is typically aluminum, because aluminum can be bent to tight radii without cracking or losing structural integrity. Vinyl and fiberglass frames can accommodate moderate curves but have limits on minimum bend radius.
This custom manufacturing process takes significantly longer than producing a standard rectangular window. Lead times of 8 to 16 weeks are typical for custom shapes, compared to 4 to 8 weeks for standard sizes. Complex or very large shapes may take even longer. Planning ahead is essential, especially if you are coordinating a custom shape order with a larger window replacement project and want everything installed together.
Benefits of Custom Shape Impact Windows
Choosing impact-rated custom windows over plywood covers, decorative shutters, or non-impact glass in your specialty openings delivers a range of advantages that go beyond aesthetics.
Preserve Architectural Character
Maintain or restore arched transoms, circular accents, and triangular gable-end windows that define your home's design, all while meeting current Florida Building Code standards.
Complete Building Envelope
A single unprotected decorative window is a hurricane failure point. Custom shapes close every vulnerability, giving you uninterrupted protection across every opening.
Full Insurance Credit
Every opening must be impact-protected for the maximum wind mitigation discount. Custom shapes ensure your specialty windows don't cost you the full insurance savings.
Natural Light & Design Flexibility
Arched transoms brighten foyers, triangular gable windows flood vaulted ceilings with daylight, and circular accent windows add visual interest with ambient light.
Zero Maintenance
Fixed (non-operable) design means no moving parts, no operator hardware, and no weatherstrip seals to wear out over the life of the window.
Superior Weathersealing
Fixed construction delivers some of the best air infiltration and water penetration performance of any window type, with high DP ratings relative to their size.
Every Opening Matters in the HVHZ
A home's hurricane protection is only as strong as its weakest opening. If you install impact windows and doors throughout the house but leave a non-impact decorative window unprotected, that single opening becomes the failure point during a hurricane.
Pairing Custom Shapes with Operable Windows
Since most custom shapes are fixed, they are frequently designed as part of a larger window assembly that includes operable units. Common combinations include a half-round arch transom above a pair of casement windows or a rectangular single-hung, a triangular gable window above a row of horizontal rollers, and a full-round accent window flanked by operable casements. When ordering these combinations, make sure the custom shape and the operable units come from the same manufacturer and product line so that the frame profiles, finish colors, and glass appearance match perfectly.
Decorative Options
Custom shape impact windows offer several decorative options that can enhance the architectural impact of the window:
- Internal grilles and grids: Simulated divided lite patterns (SDL) placed between the glass panes create the appearance of individual glass panes without affecting the impact performance of the laminated glass. Grid patterns include colonial, prairie, and custom configurations.
- Tinted glass: Gray, bronze, green, and blue tints reduce glare and solar heat gain while adding a subtle color accent. Tinted glass can be combined with Low-E coatings for maximum energy performance.
- Low-E coatings: Even on decorative or accent windows, Low-E coatings reduce solar heat gain and improve energy efficiency. On south-facing or west-facing arch transoms that receive direct sun exposure, a Low-E coating can meaningfully reduce cooling loads.
- Obscure and textured glass: For privacy applications such as bathroom accent windows, obscure or textured laminated glass provides diffused light without visibility. Pattern options include rain, hammered, frosted, and several others, though availability varies by manufacturer.
- Custom frame colors: Beyond standard anodized and powder coat finishes, most manufacturers offer custom color matching for an upcharge, allowing the frame to blend seamlessly with any exterior paint scheme.
Impact Rating and Code Compliance
Custom shape impact windows must meet exactly the same testing and certification requirements as standard rectangular products installed in the Miami-Dade HVHZ. There are no exemptions or reduced standards for decorative or specialty shapes.
Frame Material Options
The choice of frame material depends on the geometry of the shape, the size of the opening, and your priorities for aesthetics, energy performance, and budget.
Aluminum Frames
Pros
- Can be roll-formed to precise radii for curves
- Only practical option for tightly curved shapes
- Structural strength for large custom shapes
- Wide range of powder-coat and anodized finishes
Cons
- Higher cost than vinyl for straight-sided shapes
- Conducts heat without thermal break
Best for: All curved shapes (arches, circles, eyebrow), large custom panels, and any tight-radius geometry
Vinyl Frames
Pros
- Excellent thermal insulation
- Lower cost for straight-sided shapes
- Corrosion-resistant, no painting required
- Suitable for triangles, trapezoids, octagons
Cons
- Cannot be bent into curves
- Limited to straight-segment shapes only
- Bulkier profiles than aluminum
Best for: Straight-sided custom shapes (triangles, trapezoids, hexagons, octagons) where budget and energy efficiency are priorities
Cost Range for Custom Shape Impact Windows in Miami
Custom shape impact windows are among the most variable in pricing because every unit is made to order, and the cost depends heavily on the specific shape, size, glass configuration, and manufacturing complexity. Here are general installed price ranges for the Miami-Dade and Broward County market:
Small Accent Shapes (octagon, hex, circle <24")
Standard laminated glass, aluminum frame
Half-Round Arch Transoms (36"–60")
Most common custom shape
Triangles & Trapezoids (36"–72" base)
Large/Complex Shapes (full-round >36", gothic)
Very large or complex may exceed this range
For pricing on standard rectangular window types, including how they compare to custom shapes, see our cost guide.
What Drives Custom Shape Costs Higher
- Shape complexity: Curves cost more than straight segments. A half-round arch is more expensive per square foot than a triangle of equal area because the frame must be roll-formed to a precise radius and the glass must be cut along a curve with no tolerance for error.
- Size: Larger shapes require more material, thicker glass to meet DP requirements at the larger span, and more labor for installation. Very large custom shapes may also require structural reinforcement of the rough opening.
- Glass upgrades: SGP interlayer, Low-E coatings, insulated laminated glass, tinted glass, or decorative options (internal grilles, textured glass, obscure patterns) each add to the cost. For large curved panels, an SGP upgrade may be required rather than optional to meet the DP rating at the specified size.
- Minimum order quantities: Some manufacturers require minimum order quantities for custom shapes. If you need a single specialty window, you may be paying a premium compared to ordering multiple custom units as part of a larger project.
- Lead time and scheduling: The extended manufacturing lead time (8 to 16 weeks or more) can affect project scheduling. If your custom shapes arrive weeks after the standard windows, you may face additional mobilization charges for the installer to return for a second installation visit.
- Template and measurement costs: Curved and irregular openings often require the installer to create a physical template of the rough opening to ensure the manufactured window fits precisely. This adds a pre-order step that rectangular windows do not require.
What to Look For When Buying Custom Shape Impact Windows
Purchasing custom shape impact windows requires more planning, communication, and verification than ordering standard rectangular units. Here is a practical checklist for Miami homeowners.
At National Glass & Construction, we have extensive experience with custom shape impact windows across Miami-Dade, Broward, and Palm Beach counties, from small decorative octagons to large arched transoms spanning six feet or more. We handle field measurement, templating, manufacturer coordination, permitting, installation, and final inspection. Whether you need a single accent window or a full set of custom shapes as part of a whole-home window replacement, contact us for a free consultation and detailed estimate.
For a broader look at all impact window styles, including single-hung, horizontal rollers, picture windows, and casement windows, return to our main impact windows guide. For entry point protection, see our impact doors and hurricane protection guides.
Ready to Protect Your Miami Home?
National Glass & Construction has been installing impact-resistant doors and windows across South Florida for over 35 years. Get your free, no-obligation estimate today.