Architectural Specialty Shapes

Half-round (semicircle): the most common specialty shape. Appears as transoms above entry doors, above rectangular windows in Georgian and Federal-style homes, as standalone gable-end windows in colonials. Typical sizes 24-72 inches wide. Standard fabrication, available from Andersen, Pella, Marvin in stock and custom sizes.

Full-round (circle): less common but used as accent windows in gables, stairwells, and ornamental applications. Range 18-48 inches diameter typical. Fabrication straightforward — circular cut tempered glass in custom-formed frame.

Eyebrow (elliptical low arc): the signature window of Shingle Style, Queen Anne, and Tudor Revival architecture. Low-rise elliptical curve over a rectangular base. Tricky to fabricate because the curve is non-circular — has to be templated from the actual opening or specified with precise rise/span dimensions. Common in NJ on homes from 1890-1930.

Gothic arch (lancet, pointed arch): pointed-top arch with vertical sides. Common on Gothic Revival homes (1840-1900) and on churches throughout NJ. Fabrication requires custom-bent frame components — we partner with specialty fabricators for the arch top assembly.

Palladian/Venetian: tripartite window with a central arch-top section flanked by rectangular side sections. The full assembly is mulled. Common on Georgian Revival homes in Princeton, Madison, and Summit. Either factory-mulled by Andersen or Marvin for new construction or field-assembled for historic restoration.

Octagonal: 8-sided geometric shape. Used as accent windows in gable peaks and stairwells. Stock sizes from most major manufacturers; custom sizes require fabrication to match the existing opening.

Trapezoidal: 4-sided shape with non-parallel top and bottom (or sides). Used in gable peaks, attic windows, and contemporary architecture. Always custom-fabricated to the specific opening angle.

Custom irregular: anything that doesn't fit a standard geometric description. We've fabricated kidney-shaped windows for Art Nouveau renovations, asymmetric pentagons for modernist additions, and custom radius matches for restoration where the original opening was hand-cut decades ago.

Stock specialty shapes from major manufacturers: half-rounds, full-rounds, octagonals in standard sizes from Andersen 400 Series, Pella Architect Series, Marvin Elevate. Lead times 4-6 weeks. Limited size and configuration options but well-priced and quick.

Custom specialty shapes from major manufacturers: same product lines in custom sizes and configurations. Lead times 8-12 weeks. The manufacturer fabricates the frame to your template and ships ready to install. Wider size range and configuration options than stock; higher cost than stock by 30-60%.

True custom from specialty fabricators: Reilly Windows & Doors, H Window Company, Marvin Modern, and a handful of NJ-area specialty millwork shops fabricate true custom geometry. Used when major-manufacturer options don't fit the opening or the historic profile match isn't achievable with manufacturer products. Lead times 12-20 weeks; cost 2-5x major-manufacturer custom.

Historic restoration with hand-fabricated wood sash: a different category entirely. NJ has a handful of restoration carpentry shops that hand-fabricate wood sashes to match original profiles — Old House Authority in Cape May, Architectural Restoration Co in Burlington County, and several smaller artisan shops in the northwest counties. Lead times 16-30 weeks; cost is by-the-job and runs into five figures for major historic windows.

Standard rectangular windows ship in 4-6 weeks. Add 2-4 weeks for stock specialty shapes. Add 6-10 weeks for custom manufacturer. Add 8-16 weeks for true custom fabrication. Add 12-26 weeks for historic restoration. Customers need to plan their renovation schedules around these lead times — there's no expediting custom glass fabrication.

Rectangular windows are measured with a tape and you're done. Specialty shapes require physical templating — a paper or cardboard pattern cut to the exact opening, verified to fit the opening, and shipped to the manufacturer along with the order.

Our standard templating process: lay heavyweight kraft paper or pattern board (a stiffer cardboard product) against the rough opening from the interior. Trace the perimeter using a fine marker, follow the actual edge contour. Cut the template along the trace line. Test-fit by holding the template back against the opening. Mark interior/exterior orientation, opening dimensions, and the home address and customer name on the template. Photograph the template against the opening. Ship to manufacturer.

For eyebrows and ellipses we specify rise and span instead of pure template — the manufacturer prefers a mathematical description. Rise: vertical distance from the highest point of the arc to the chord line. Span: horizontal distance across the chord line. From these two dimensions the manufacturer reconstructs the elliptical curve.

For Gothic arches and Palladians we template the full opening. For curved muntin patterns in restored Palladians the templating is even more critical — we template each individual muntin segment separately and verify the assembly fits the opening exactly before final fabrication.

Digital templating for high-end work: Faro arm or photogrammetry capture for sub-millimeter accuracy on irregular openings. Used on restoration projects where the original opening is hand-cut and slightly asymmetric — the digital scan captures the actual geometry rather than approximating with a paper template. Adds $200-500 to the templating cost but eliminates fit issues on $5,000+ specialty windows.

Original 1880-1940 wood sashes have distinctive features that modern stock windows don't replicate. Muntin profiles are typically 7/8" or 1" wide with a putty-glazed bevel, compared to modern aluminum or vinyl muntins at 5/8" with snap-in profiles. Sash construction is true divided light (each pane is individually glazed in its own muntin pocket) rather than simulated divided light (a single piece of glass with muntin grilles applied to the surface).

True divided light is available from Marvin (TDL option on Ultimate and Elevate lines), Andersen (TDL on E-Series), and Pella (Architect Series Reserve). Cost premium is 40-80% over simulated divided light. For historic district work the cost is often worth it — historic preservation commissions sometimes require TDL for certificate-of-appropriateness approval.

Restoration glass — period-appropriate glass with subtle waviness, slight imperfections, and the characteristic 'sparkle' of pre-1940s float glass production. Available from Bendheim Restoration Glass in their Restover, Restoration, and Reamy products. Used when the visual character of the glass itself matters, not just the muntin pattern. Premium cost (2-4x modern float glass) but visually transformative for historic restoration.

Putty glazing rather than glazing tape: original wood sashes used linseed-oil putty (Sarco Type-M or Aborganic equivalent) tooled to a triangular bead on the exterior face. Modern windows use glazing tape and rubber gaskets, which read as wrong on a historic restoration. We can spec putty glazing on custom wood sashes for restoration work — adds labor but matches original appearance.

Hardware: original lift weights, sash locks, and brass hardware aren't compatible with modern weatherstripped windows. For true restoration we either restore original hardware (typically possible) or source period-correct reproductions from Eastlake Co, Liberty Brass, or similar restoration hardware suppliers.

Specialty shapes don't get a pass on structural requirements. A 60-inch-wide half-round transom over an entry door has to meet the same DP rating as a rectangular window of equivalent area. The curved top distributes load differently than a flat top, which affects glass thickness requirements — typically requiring slightly thicker glass than a rectangular equivalent.

Mulled assemblies with specialty shapes — a Palladian with rectangular sides and an arched center — concentrate stress at the mullion joints between the curved and straight sections. Structural mullions need to be sized for the assembly load, not just the individual unit load.

Coastal applications require impact-rated glass for any opening in the wind-borne debris zone. Custom-curved impact glass is more expensive than rectangular impact glass and has longer lead times — typically 14-20 weeks vs 8-10 for rectangular. We've fabricated coastal-rated half-rounds, octagonals, and full-rounds for Cape May, LBI, and Stone Harbor properties.

Historic restoration in coastal zones is a special challenge. Original 1890s wood sashes don't meet modern impact code, but the historic district may require their preservation. The solution is often a custom storm panel — a removable impact-rated panel that's installed in front of the original sash during storm season and removed at other times. We coordinate with the historic preservation commission on these solutions.