Building Type
Movie Theater & Cinema Roofing with scope notes, photos, and next steps.
A multiplex roof is unusual because there is nothing underneath it. Each auditorium is a wide, column-free room, so the roof deck bridges 80 to 150 feet in a single span — and that same deck is the surface that has to keep audiences dry, keep theater sound from bleeding between rooms, and hold the air conditioning steady in a packed house. Around Fort Lauderdale the cinemas we walk include the big stadium-seating multiplexes anchoring retail centers along the Federal Highway and State Road 7 corridors, the dine-in entertainment houses near the Galleria and downtown Las Olas, and screens built into the mixed-use development pushing through Flagler Village. None of those roofs behave like the strip-center next door, and we do not spec them that way.
Those clear-span bays flex. A long steel deck over an auditorium deflects under wind and load in a way a short retail span never does, and a fastening pattern copied from a strip-mall roof will work itself loose at the seams over time. We verify the actual deck type, gauge, and rib depth and pull-test it before committing to an attachment method, because older shallow-rib deck holds far less than modern deep-rib deck. Where deflection is a real concern across a wide bay, we will move to an adhered or hybrid system so the load is spread across the membrane instead of concentrated on fasteners at the seams.
Cinema rooftops are crowded. Each auditorium usually has its own rooftop HVAC unit sized for a full house, and on top of that sit concession exhaust, kitchen and bar makeup-air for the dine-in formats, restroom vents, and condensers for the walk-in coolers feeding food service. The result is a curb cluster that rivals a hospital or data center, and every one of those curbs, ducts, and conduit runs is its own flashed and documented detail. We inventory the whole field before tear-off so nothing gets reflashed by assumption over an occupied building.
On a theater the roof assembly is doing acoustic work, not just weatherproofing. It is the barrier that keeps the action sequence in screen 6 out of the quiet drama in screen 7, and it has to dampen the drumming of a hard Fort Lauderdale downpour so it does not carry into the auditorium during a quiet scene. When we recover or replace, we protect the existing acoustic and insulation performance of the deck assembly and avoid details that telegraph rain noise or open a sound path between bays. The big rooftop units also vibrate, so we isolate and detail those curbs so equipment hum is not transmitted into the rooms below.
Wide flat theater roofs pond, and decades of minor deck deflection only make the low spots worse. Standing water through our long wet season is the fastest way to age a membrane, so most cinema reroofs here get tapered insulation built to push water to the drains and scuppers. A white reflective membrane does double duty: it meets the cool-roof side of the energy code that applies to commercial reroof permits and it cuts the rooftop heat load feeding the auditorium air conditioning. Around the busy rooftop units we add reinforced walkway pads so the constant HVAC service traffic does not wear through the field membrane.