Delray Beach Reviews the Glass Itself, Not Only the Window

A typical impact window quote answers two questions: what the unit costs and what pressure it holds. Delray Beach's adopted Historic Preservation Design Guidelines ask for considerably more. The Windows section sets out what a replacement design must take into account, in the city's own order: "Trim detail; Material; Size and shape of frame and opening; Reveal or setback of the window from the wall plane; Light configuration; Whether the horizontal line of the sash is on the same, or different, plane; The color and reflective qualities of the glass; and The muntin and mullion profiles and their configuration."

Read that against a quote and the gaps show. Reveal, meaning how far the frame sits back from the wall plane, is decided by the installation detail and is almost never discussed. "The color and reflective qualities of the glass" is a line a tinted low-emissivity unit can fail on appearance while passing every structural test it was built for. "The muntin and mullion profiles and their configuration" is the difference between a genuinely divided light and a grille sealed inside laminated glass, and on a small pane those two do not look alike from the sidewalk.

The guidelines also treat impact glass as a permitted route rather than a way around appearance: "The Building Code does allow for the installation of impact-resistant glass in place of a shuttering system... In any case, the new windows should resemble and reconfigure a historically appropriate type." That is guidance from an adopted document rather than a local amendment to the code, and it is applied through the Certificate of Appropriateness, not by a structural inspector on the last day.

Of the five districts on the Local Register, the city describes Nassau Park as "The only historic district east of the Intracoastal Waterway." Everything else on the register sits on the mainland side. One sentence, and it tells you that in this city high barrier-island exposure and appearance review overlap in exactly one place — which is also the place where the specification is hardest to satisfy from both directions at once.

The city's adopted Coastal Management Element describes that island: a coastal planning area of roughly 629 acres, about three miles of beach front, a barrier island varying in width from 1,000 to 2,000 feet, essentially built out, overwhelmingly residential, with more than half the area zoned for single family detached housing. It is an older adopted document, so read those figures as the city's own description rather than as this year's count. The shape of the problem has not moved: a narrow island, small lots, high exposure, and one district where how the window looks is reviewed as well as what it holds.

Two of the five local districts are also listed on the National Register, and the seven-member board administering all of them was created under the city's 1987 preservation ordinance. That is a long-established program working from a written, adopted set of guidelines, which is the reason to treat the eight-item list as a specification sheet rather than as a reviewer's mood on the night. A board applying the same document decade after decade is predictable, and predictable is exactly what you want when the unit is made to order and the deposit is already down.

1. 01Establish whether the address sits in one of the five districts on the city's Local Register — West Settlers, Old School Square, Del-Ida Park, Marina or Nassau Park — or is an individually listed property.
2. 02Treat the eight-item list as the specification sheet and answer every line in writing before a unit is ordered.
3. 03Select glass on appearance as well as on performance, since color and reflectivity are named review items.
4. 04Settle whether muntins are divided or applied, and show the profile, because configuration is reviewed rather than assumed.
5. 05Route the work correctly, to preservation staff or to the seven-member Historic Preservation Board, depending on the extent of the work.

The guidelines say replacement with the original material is always most desirable, and that the board "will consider other materials or cladding on a case-by-case basis." We read that as an invitation to make a case rather than as a refusal, and a case is far easier to make with a physical sample, a profile drawing and a marked-up elevation than with a brochure page. On jobs in this city we spend more time on appearance documentation than on anything else, and it is the cheapest time on the whole job.

Source: City of Delray Beach Historic Preservation Design Guidelines, the city's historic districts page and its adopted Coastal Management Element — checked 2026-09-24