Most commercial skylight leaks in Salt Lake City are not glazing failures - they are flashing failures at the curb, driven by freeze-thaw cycling that progressively loosens the flashing termination at the skylight frame. We determine which component is failing, repair or replace it, and verify the assembly before the next freeze season.

Commercial skylights on Salt Lake City flat-roof buildings - present across the retail, restaurant, institutional, and adaptive reuse sectors, and increasingly common in the mixed-use redevelopment occurring in Sugar House, the 9th and 9th area, and the emerging mid-block corridors in the Granary District - present a specific repair challenge in Utah's climate. The skylight is a composite assembly of framing, glazing, and curb flashing, and leaks can originate from any of the three components or from their interfaces. The Wasatch Front climate stresses all three more aggressively than many commercial markets.

The most common source of skylight leaks is the curb flashing - the roofing membrane that transitions from the horizontal roof field up the vertical face of the skylight curb and terminates under the skylight frame. This flashing fails through separation at the termination, membrane shrinkage, and UV degradation of the sealant at the frame-to-flashing interface. In Salt Lake City, freeze-thaw cycling accelerates this failure mechanism: the thermal expansion differential between an aluminum skylight frame and the membrane termination bar below it is sufficient to progressively open the sealed joint over two to four winter seasons if the initial installation was not designed with adequate flexibility.

Glazing failures - yellowing, crazing, and surface cracking of acrylic or polycarbonate panels - are a separate category of problem. At 4,226 feet elevation, UV radiation is measurably more intense than at coastal or Midwest commercial markets, and the UV stabilizers in acrylic panels are consumed more rapidly. An acrylic skylight panel on a Salt Lake City commercial building showing significant yellowing is already past the point of reliable structural performance under hail impact.

Curb Flashing Rebuild for Freeze-Thaw Conditions

A curb flashing rebuild strips the existing base flashing from the curb face, cleans and primes the curb substrate, and installs new membrane flashing in accordance with the roofing system manufacturer's curb detail. On Wasatch Front TPO systems, the base flashing is heat-welded to the field membrane at the curb base and mechanically terminated at the top of the curb face under the skylight frame. The frame interface sealant must accommodate not only the thermal movement of an aluminum frame - which moves significantly across Utah's July-to-January temperature range - but also the differential movement between the frame and the membrane termination bar as they respond to temperature changes at different rates.

We use manufacturer-specified flexible sealants at frame interfaces on every skylight repair - rigid caulks that look intact at installation fail within two to three Utah freeze-thaw seasons at this joint. We document the sealant product used in the repair record so future repairs have a compatibility baseline.

On multi-unit skylight installations - common in retail and light-industrial buildings across the Wasatch Front - we assess all units during a single mobilization. Units that share flashing runs often show progressive failure from the upslope unit downstream. Repairing one unit in a shared-flashing configuration while leaving adjacent units in marginal condition typically produces a callback within one season.