1. Article Body
Restaurant roofs fail in a pattern you can predict from the kitchen layout. Stand at the hood fan, note the prevailing wind, and you have mapped most of the damage before climbing anywhere.
Grease degradation around the exhaust
The membrane downwind of the hood fan is the first thing to fail on almost every restaurant roof.
On a susceptible material the surface softens, loses plasticizer, becomes tacky and eventually splits. The affected area grows outward from the fan over years.
Where grease containment is absent, saturated or overdue for service, this accelerates sharply.
Condensate saturation
Restaurants carry a lot of refrigeration. Walk in coolers and freezers, reach ins, ice machines and comfort cooling all produce condensate, and the lines discharge onto the roof.
A line that drips continuously on a shallow slope creates a permanently wet zone. The membrane degrades, the insulation beneath saturates, and the weight increases exactly where the structure is already deflecting.
Hood cleaning damage
Hood cleaning is a wet, chemical process carried out on the roof around the fan, often at night, often by a crew with no instruction about the roof.
Detergent, pressure washing and dragged equipment all damage membrane. The damage concentrates in exactly the area already weakened by grease.
Curb and penetration failures
Restaurant roofs carry many curbs relative to their area. Makeup air, multiple condensers, exhaust fans, the grease duct.
Curbs set too low cannot be flashed correctly. Equipment replaced on an existing curb frequently leaves the flashing disturbed. Each equipment change is a potential leak.
Foot traffic and service paths
Refrigeration failures are emergencies in a restaurant, so technicians attend at short notice and walk the shortest route.
Without walkway pads, the informal path from the hatch to the equipment wears through the surface. This is visible as a discolored track and it is entirely preventable.
Ponding at the low points
Shallow slope plus rooftop equipment plus deflection produces low areas that hold water. Combined with grease and condensate, a ponding area on a restaurant roof degrades faster than the same ponding on an office building.
Drain blockage
Grease, food packaging debris and leaf litter block drains and scuppers. A restaurant drain needs clearing more often than a comparable commercial one.
Abandoned equipment
Restaurants change hands and change menus. Old fans, disused condenser bases and redundant ducts stay on the roof as penetrations long after the equipment they served has gone.
Audit them at every reroof and remove rather than reflash.
