Commercial Skylight Repair.

Commercial skylights in New Orleans face a combination of UV exposure, tropical humidity, and hurricane wind loading that accelerates flashing and glazing failure faster than most building owners anticipate. We diagnose the actual failure point and repair it with a detail that holds through the next storm season.

Commercial skylights on New Orleans flat-roof buildings are a concentrated failure risk. The curb flashing — the roofing membrane transition from the horizontal field up the vertical skylight curb face — is exposed to some of the highest UV loads on the roof because skylights are typically sited on south-facing roof slopes and because the curb geometry creates a thermal bridge that elevates surface temperatures above the surrounding membrane. In New Orleans's subtropical climate, where July and August roof surface temperatures regularly exceed 160 degrees Fahrenheit on dark-surface systems, that thermal concentration accelerates base flashing separation at the curb termination and sealant degradation at the frame interface.

Skylights on New Orleans commercial buildings carry an additional risk factor that is not present in most US markets: hurricane wind pressure at the glazing surface. Flat acrylic and polycarbonate skylight panels generate negative wind pressure under certain storm approach angles that can lift the glazing panel from its frame before the storm produces surface impact damage. On buildings in open-terrain exposures — the New Orleans East warehouse corridor, the lakefront commercial zone in Metairie, the Veterans Boulevard corridor — the uplift loads on skylight glazing can exceed the structural rating of older acrylic panels. We assess wind-load adequacy on every skylight inspection we conduct.

The most common skylight repair in this market is a curb flashing rebuild combined with frame-to-flashing interface resealing. The second most common is glazing replacement on acrylic panels that have yellowed and become brittle from UV depletion of their stabilizer package. We diagnose which component has failed before recommending either repair, and we do not replace glazing when the flashing is the source of the leak or vice versa.

A curb flashing rebuild strips the existing base flashing from the skylight curb face, cleans and primes the curb substrate, and installs new membrane in accordance with the roofing system manufacturer's published curb detail. On TPO systems, the curb flashing is heat-welded to the field membrane at the curb base and mechanically terminated at the top of the curb under the skylight frame. On modified bitumen systems — present on a significant portion of the pre-2000 New Orleans commercial inventory — the curb flashing is torched into the field membrane and terminated with a metal counterflashing reglet and elastomeric sealant.

The frame-to-flashing interface is the most critical joint in the curb assembly. The gap between the skylight frame's base and the flashing termination must be sealed with a sealant that is both compatible with the membrane and flexible enough to accommodate the thermal movement of the aluminum frame. In New Orleans's climate, aluminum skylight frames experience thermal expansion and contraction across a temperature range from winter cold front lows near 35 degrees Fahrenheit to summer surface temperatures above 130 degrees Fahrenheit — a range that produces measurable frame movement at the sealant joint. A rigid caulk at this joint fails in two to three seasons. We use manufacturer-specified flexible sealants at frame interfaces and document the product in the repair record.

Hurricane wind-load reinforcement at the curb-to-roof-membrane transition is considered on buildings in open-terrain exposure categories where the corner and perimeter pressure coefficients under ASCE 7 hurricane-prone-region loading exceed the standard curb flashing detail's holding capacity. We discuss this reinforcement with the building owner when the building's exposure history or site conditions warrant it.

Glazing replacement on New Orleans commercial buildings requires a material specification decision that accounts for both UV performance and hurricane hail exposure. Flat acrylic panels — the standard glazing on most commercial skylights installed before 2005 — degrade in UV stabilizer content after 12 to 18 years in the New Orleans climate. A yellowed, brittle acrylic panel has lost a significant portion of its structural reserve against impact and against the uplift pressures generated by tropical storm systems. Polycarbonate panels rated to FM 4881 hail impact standards are the defensible replacement specification for New Orleans commercial buildings — they carry significantly better impact resistance than acrylic and a longer UV stabilization service life.

Glazing panel replacement requires removing the skylight frame's retaining bars, extracting the failed panel, inspecting and reseating the glazing gasket, installing the new panel, and reseating the retaining bars to manufacturer-specified torque. A compressed or deteriorated glazing gasket that is not replaced during a panel change produces a leak at the frame within the first significant rain event after installation. We do not seat replacement glazing without a fresh gasket inspection, and we replace the gasket as part of every panel replacement.

Wind uplift adequacy of the skylight frame is assessed when we are replacing glazing on buildings in exposed positions. Older aluminum skylight frames may not have been specified to the post-Katrina Louisiana wind-load code amendments. If the frame's clip spacing or anchor pattern does not meet the current requirement for the building's risk category and exposure, we advise the building owner before proceeding with glazing replacement — putting a new panel in an under-anchored frame transfers the risk from glazing failure to frame failure under storm conditions.

Every completed skylight repair is water-tested before demobilization. We flood the curb for fifteen minutes and verify no water entry at the frame-to-flashing interface, the glazing gasket line, or the retaining bar seal. In New Orleans, where tenant operations in occupied commercial space — restaurants in the Warehouse District, retail along Magazine Street, hospitality properties throughout the French Quarter — can generate significant disruption and liability from post-repair leaks, we do not leave a repaired skylight without a confirmed water test.

For multi-unit skylight installations — common in mid-size retail shell buildings across Jefferson Parish and in the adaptive-reuse conversion buildings along the St. Claude Avenue corridor — we assess all units during a single mobilization. Skylight units that share flashing runs or that are sited in sequence on the same roof slope commonly show progressive failure from the upslope unit downstream. Repairing one unit while leaving adjacent units in marginal condition produces a callback within one season.

How do I know if the skylight is leaking at the curb flashing or through the glazing panel itself?

The most direct diagnostic is to hose water on the glazing panel surface only — avoiding the curb and frame entirely — and wait fifteen minutes while monitoring the interior below. If no leak appears, the glazing is intact and the source is at the curb flashing or frame interface. If water appears, the panel has a failure. We run this test as the first step in every skylight leak diagnostic so the repair scope is correct from the start.