Most commercial rooftops are resigned to house HVAC equipment, lined up in neat rows high above the street. As important as these units are to the building they are taking up some of the building’s most valuable and versatile space. Now developers and owners are starting to see new possibilities. Depending on what you do with a roof, it can serve as a building amenity, efficiency enhancement, storm mitigation, or source of locally grown food. Across urban environments, rooftops are finally getting the thought they deserve from designers, architects, and engineers.
It’s no surprise how we got here. Air conditioning has become a critical part of buildings, providing that requires bulky equipment that needs the space to exhaust hot air. Denied street space in dense cities, the simplest solution is to put the units on the roof, where they reduce clutter, noise pollution, and can be better protected. For most buildings, that means turning the roof into another basement, only accessible to maintenance workers and building staff. But rooftops aren’t basements. Access to sunlight, weather, and some of the best views in the city mean rooftops can be something more when given careful consideration.
The first step in understanding a roof’s possibility is structural analysis. Unlike basements, mostly backed by a foundation or solid ground beneath, rooftops have a maximum load capacity that if exceeded can result in collapse. How much a rooftop can hold is the basis of its potential. Next is to know the current condition or future state of the rooftop membrane, the water-tight covering or coating that keeps the building sealed from the elements. Those two elements are the most important factors in rooftop design.