Skylight and Penetration Flashing in Medford, OR

Every hole in a roof is a bet that a sealed joint will outlast the sun, and in Medford, OR the sun collects on that bet faster than the roof's budget assumes. A skylight curb, a pipe boot or a vent stack concentrates heat, movement and moisture into a few inches of flashing, and those few inches fail years before the surrounding membrane does. The leak that results is small at first, a damp ceiling tile under a skylight or a stain around a plumbing vent, and it is routinely mistaken for a problem with the whole roof.

Treated as a distinct line in the roof register, penetration flashing can be inspected and renewed on its own schedule. That keeps the field membrane in service for its full rated life and spares the owner a replacement that was triggered by a few dozen weak details.

The first step is an inventory. We walk the roof and list every skylight, hatch, pipe, conduit, vent, exhaust stack, antenna mount and support post, noting its type, its flashing material and its condition. Older roofs often carry abandoned penetrations from earlier tenants, capped lines, or former equipment, and each is a liability worth removing rather than maintaining.

Skylights come in several forms: curb-mounted units with glass or plastic domes, sloped glazed assemblies, and smoke or access hatches. Each sits on a curb, as do the rooftop equipment curbs beside them, and each curb must be flashed to the roof, and each has its own gasket, sealant and fastener details that age on a different timeline. The inventory gives the owner a clear count and a priority order, so the details that are failing today are repaired first.

For a property manager, that inventory changes how repairs are bought. A roof with sixty penetrations in fair condition and five in poor condition does not need sixty repairs; it needs five, plus a watch on the rest. Pricing the five separately keeps the carrying cost of the roof where it belongs and gives the owner a clean answer when a tenant asks why the work is limited.

Flashing material experiences more movement than a field membrane because it sits on a rigid object that expands at a different rate. With 61 afternoons over 90 F, 11 of them over 100 F in a typical year, that cycle repeats daily from May through September. Rubber boots crack where they bend, sealant loses elasticity and pulls from its joint, and metal flashings open at their laps.

Skylight domes craze and yellow under ultraviolet exposure, and their gaskets shrink. Condensation inside a unit can be mistaken for a leak, so we test before repairing: a dry interior with water staining at the curb corner confirms an exterior failure, while moisture beading on the glazing points to an interior humidity problem. After a smoke season such as the 26 smoke days of 2021, soot and ash collect at the base of every curb and penetration, holding moisture against the flashing and hiding early cracks.

Minor failures can be repaired with compatible sealant, new boot collars or a stripped-in patch of membrane. We clean and prime the surface, install the patch with the right adhesive or heat weld, and re-seal terminations. For pipes, we can use pre-formed boots matched to the membrane, which beat hand-built details in both appearance and durability, and they bond cleanly to a TPO or similar single-ply sheet.

When flashing is brittle, the better path is replacement. For curbs that have rotted or shifted, we rebuild the curb with new blocking and flash it back into the membrane in a continuous detail. Aging skylight units are replaced rather than patched when the glazing is crazed, the frame is racked or the unit lacks an insulated curb. In addition to matching the membrane, every new detail is designed with drainage in mind, so water sheds around the penetration rather than collecting behind it. A flashing failure repair that ignores the slope behind a curb will fail again.

Material compatibility deserves attention. Certain sealants attack single-ply membranes, and some metals react with one another, so we choose flashing resins, tapes and fasteners that suit the membrane under them rather than whatever is closest on the truck. Photographs before and after each repair go into the owner report with the roof location, so the same boot can be checked a year later.

A skylight is both a daylight source and a heat gain. In a valley summer, a large glazed area on a retail or warehouse roof adds load to the cooling system, and reflective dome treatments or low-solar-gain glazing reduce it. Owners considering new daylighting should weigh it against the building's cooling reserve and its tenants' lighting needs. Where a unit is no longer wanted, we remove it and infill the opening with a framed deck and membrane, which is a lasting fix.

For roofs headed toward a cool roof upgrade, penetration details are rebuilt at the same time so the new reflective surface is not undermined by old, failing flashings. That pairing makes better use of the work window than doing the field and the details in separate seasons.

Fire-rated smoke vents and access hatches have their own rules, and any replacement is made with units that carry the required rating for the opening. When a skylight sits within a roof area that has been adjusted for solar equipment or new mechanical loads, we revisit the curb height and the clearance first so nothing new blocks the flashing from being serviced.

Medical buildings and retail are the usual culprits. Medical use brings exhaust stacks, plumbing vents and mechanical curbs in number, and the tenants cannot tolerate a ceiling leak, which is why hospital roofing gets a tighter flashing schedule. Retail around Rogue Valley Mall, in the North Riverside corridor, presents long runs of roof where skylights, smoke vents and rooftop units may sit. Warehouse and distribution buildings such as those along Table Rock Road can have fewer penetrations but larger ones, including smoke hatches and exhaust fans.

In every case, the flashings are inspected during scheduled maintenance visits, and any penetration added later by another trade is documented so the owner knows what changed on the roof.