A summary of thoughts on roof decks
Roof decks are a great addition to the building program, they improve the experience and the property value. They are special places that offer elevated views, city skylines, sunsets, relaxed environments and greenery, music, delicious bites, craft cocktails, toasty fire pits, retractable shading devices, cabanas and more. They enrich the social and quality of life. Roof decks are becoming trendy and necessary in urban areas as we try to maximize the built environment and minimize the footprint.
Roof decks are complex as they come with a host of architectural and building problems that need to be solved and accounted for during the design process. Roof decks are easier to integrate when designing a new building but may need special detailing when added on to an existing building.
Roof decks shall be designed with a heightened awareness of safety in mind. In addition to the weight as higher occupancy is generally expected, these spaces shall be designed with the proper means of egress, emergency lighting, and railing.
Roof decks are habitable roofs, so they have to be relatively flat. As such, when designing a roof deck, besides the standard roof loads, we have to account the additional live loads, furniture and other more complex loads, such as water ponding, snowdrift, ice, and wind. Roof decks are an opportunity to improve the environment, urban island effect, stormwater runoff and energy efficiency as we are able to integrate green roofs and higher thermal insulation value.
In the process of design, the weight from these loads is transferred down through to the building components. On existing structures, the concern is whether the foundations are capable of supporting these additional loads. The foundations and the soil would need to be investigated. Sometimes the expansion and reinforcing of the existing footings are required.
By virtue of being the roof of the building, the roof deck must be waterproofed. It must handle the water to properly drain away with robust roofing and flashing system, able to withstand a higher traffic than a standard roof otherwise would. Having many features on the roof, such as pergolas, lighting, and furniture makes the waterproofing a challenging task. This must be carefully detailed and executed to avoid leaks that in the future would be hard to find and expensive to repair.
There are other issues and considerations of noise, materials, and sound in play but overall, if carefully and professionally designed, roof decks are an enhancement of the building, an enjoyable space that strengthens the indoor-outdoor connection.
We have designed a few projects with integrated roof decks and would love to see more of these being engaged in our communities. Let us know your thoughts.