Rooftop Deck Materials for Miami High-Rises and Terraces

Roof decking vs. a rooftop deck: not the same thing

A search for rooftop deck materials returns two different layers of a building. In roofing, the deck is the structure itself: the National Roofing Contractors Association (NRCA) defines it as a structural component of the roof, the substrate that carries the building’s loads and receives the roofing or waterproofing system. Concrete, metal deck, gypsum and plywood are roof deck materials in that sense.

A rooftop deck is the walking surface built on top of that assembly so people can use the roof: a private terrace, a pool level, an amenity lounge or a hotel bar. It sits above the waterproofing membrane, and every material choice in this guide is judged by how it treats that membrane.

This guide covers the second meaning, for condo towers, office buildings and hotels in Miami.

What a Miami rooftop puts a deck through

A deck on a Miami roof takes heavy rain, strong sun and humid air at the same time, with little around it for shade or shelter. According to the National Weather Service office in Miami, the South Florida wet season runs from May 15 to October 15 and accounts for 60 to 70 percent of the average yearly rainfall, with near-daily showers and thunderstorms and dewpoints in the 70s almost every day.

On a flat roof, all of that water has to leave quickly. Water held under a deck keeps the membrane wet and the space beneath it humid, so the deck has to leave a clear path to the drains and scuppers. Sun works on the boards themselves, on their color and surface temperature. Buildings along Biscayne Bay in Brickell and Edgewater also take salt air off the water, and connector manufacturer Simpson Strong-Tie lists ocean salt air among the conditions that cause corrosion in building hardware, which puts exposed screws at risk.

Wind and weight complete the list. How much load the roof can carry and how the deck is secured against wind are design questions for the project’s structural engineer and the building, and they are settled before materials are chosen.

Protecting the membrane: frames, drainage and access

The membrane under a rooftop deck is the building’s waterproofing, and at some point someone will need to see it to trace a leak, check a seam or clear a drain. Membrane manufacturer Polyglass recommends a protection and drainage mat over its membranes so water moves freely to drains and outlets, and its technical bulletin states that its warranty does not cover removing or replacing overburden needed for inspection or repair unless the warranty says so. On a rooftop, the deck is that overburden, so how easily it comes up shapes the cost of any future membrane work. Pedestal systems are common on rooftops because they raise the surface off the membrane. Exterpark builds the deck on an aluminum substructure, with each board held by the patented Shark Clip and removable on its own.

Board options: composite, bamboo and hardwood up high

With the membrane protected, the board is the part guests see and touch. The three Exterpark lines for rooftop decking install on the same Shark Clip and aluminum frame, a system the manufacturer says installs up to 3x faster than screw-down decking. The choice comes down to appearance, upkeep and traffic.

Residential terraces vs. hotel and amenity rooftops

The same materials work differently depending on who uses the roof and how often. A private terrace decking project on a penthouse sees light traffic and an owner who can schedule upkeep any week. An amenity deck or a hotel rooftop handles crowds, furniture moves and events, and in hospitality decking the real cost of maintenance is every day the space stays closed.

Rooftops in Brickell and Downtown Miami

Brickell, Downtown and Edgewater hold much of Miami’s high-rise rooftop space: amenity levels in condo towers, private terraces on upper floors and hotel bars facing Biscayne Bay. Projects there share the conditions above, along with the logistics of building on a tower roof, where deliveries are coordinated with the building’s loading schedule.

For deck installation in Brickell and Downtown, Exterpark supplies boards and the aluminum substructure from its warehouse in Hialeah through Cedro Rojo, its authorized distributor in the United States. Product lines and project types for the neighborhood are on the page for decking in Brickell.

Permits and approvals for rooftop work depend on the building and the scope. Confirm them with the city’s building department, the building’s management or association and a structural engineer before the project is specified.