1. Article Body
Warehouse roofs fail at the edges and at the holes. The field of a large roof is usually the healthiest part of it.
Perimeter and corner uplift
Wind pressure concentrates at corners and along edges. A failure that starts at an unsecured edge peels inward and can take a large area in a single event.
Look for lifted or displaced edge metal, loose coping, and any point where the membrane termination has pulled.
On older buildings, check whether the edge metal meets current attachment standards at all.
Skylight and translucent panel failure
The single most common leak source on a daylit warehouse.
Curbs fail at the flashing. Panels yellow, craze and embrittle. Sealants at the panel perimeter shrink and open.
Aged panels are also a fall hazard. Treat every translucent panel as unable to hold weight unless it has been verified, and use fall protection accordingly.
Membrane flutter fatigue
Mechanically attached single ply membranes billow under wind. Over years, sustained flutter fatigues the fasteners and works the seams.
The symptom is fastener backout visible as regular raised lines across the field, and opened seams on the windward side.
Sprinkler and fire protection penetrations
Piping supported from the structure, hangers, and any point where the system was modified during a fit out.
Warehouses are refitted often as tenants change, and each refit adds penetrations made by trades other than the roofer.
Drainage across a very large area
A large low slope roof concentrates a great deal of water into relatively few drains.
One blocked drain floods a large area. Deflection between structural bays creates low points that hold water. Internal drains carry water through the building, so a drain failure discharges inside.
Tapered insulation, where present, was designed for the original drain arrangement and may not match a roof that has since been modified.
Thermal movement on metal roofs
Where the warehouse has a metal panel roof, the runs are long and the movement is substantial. Fastener holes elongate and seams open, concentrating at the terminations.
Foot traffic from tenant fit outs
Warehouses change tenants. Every fit out brings electrical, mechanical, communications and racking contractors, several of whom access the roof.
Damage clusters along the route between the hatch and whatever was installed.
Condensation on the underside
An unheated or lightly conditioned warehouse with a large cold deck produces condensation that drips onto stored goods.
Operators report it as a leak. It appears across the plane rather than at a point and it appears in cold weather rather than during rain.
