Watch Full Episode

If you live in a building or home that has a large, relatively flat roof area, it can make a great place to build a deck with a view to enhance your outdoor living space. In this article, I will discuss key considerations when adding a low-maintenance composite deck and railings to the roof of a building. Keep reading to learn everything you need to know about how to build a rooftop deck. 


    Things to Consider When Building a Rooftop Deck

    Building a rooftop deck requires taking into account both the current state of your roof as well as the specific needs that come with designing an outdoor space. You need to verify that building a deck on your roof is not a violation of local building codes or neighborhood rules. 

    Today’s Homeowner Tips

    It’s best to partner with an experienced contractor for this project to ensure structural integrity and proper integration with your current roofing system. I recommend having all plans reviewed and approved by all applicable agencies before construction.

    Rooftop Deck Planning and Design

    Safety is vital when planning a rooftop deck, especially if children or aging adults will be using the space. Handrails are a must for this type of project. You or a contractor should reinforce them and check that they meet all code requirements. 

    There are also several questions you should ask before finalizing the design of your deck. Key questions to consider beforehand include:

    • What is the deck’s intended use? The layout and material choices for your deck will differ if you want to entertain large gatherings versus homeowner-only use.
    • Which decking material makes the most sense for your regional climate exposure? Some composites withstand moisture and sun better than others.
    • Could a rooftop deck positively or negatively impact your home’s future resale value? A rooftop deck adds livable space but may deter buyers who are concerned about the roof’s life span.
    • How will contractors safely access the roof for initial and future construction needs? Proper tie-off points and fall protection are essential.

    Once your final design is complete and approved, you can begin building your deck.

    Rooftop Deck Foundation

    A rooftop deck requires a strong foundation. It’s best to avoid screwing or nailing through the roof to prevent leaks. Adjustable and freestanding pedestals are an ideal way to carry the weight of the deck. 

    In this example project, we used Bison adjustable deck supports. These supports allowed us to adjust the height and pitch so that the final project would be level on the roof.

    Pressure-treated wood joists placed appropriately handle the span and weight of the deck. The joists were then fastened to the supports to complete the framework.

    Today’s Homeowner Tips

    I recommend using corrosion-resistant hardware for this project to protect your deck from the elements. 

    Installing Composite Deck Boards

    After completing the deck’s foundation, we installed tongue-and-groove composite decking from TimberTech boards. We screwed the boards to the joists using hidden fasteners for a durable and low-maintenance result with no exposed screws. 

    Composite decking often requires the joists to be closer together than wood decking, as composite material is not as rigid as wood. We chose a composite decking option designed for joists on 24-inch centers, which reduced the number of joists required. 

    Composite Railing System

    Deck railings are essential for safety on elevated decks. Fortunately, they can also enhance the beauty of your outdoor living space with a thoughtful design. 

    For this rooftop deck, TimberTech RadianceRail composite balusters and post sleeves were combined with wood rails and posts to create a low-rail system.

    The 4×4 treated wood posts for the railings were covered with composite sleeves that slid over the posts.

    After the composite rails had been screwed to the balusters and attached to the posts, the top was covered with a composite handrail to hide the screws.

    So, Is Building a Rooftop Deck Worth It?

    Adding deck space on top of a roof is a great way to expand your living area to enjoy beautiful views and entertainment. However, constructing any kind of elevated structure means that you must account for additional safety considerations. I also recommend choosing long-lasting, durable, and low-maintenance materials so that your upkeep is minimal.

    It’s best to hire an experienced deck builder who is well-versed in local building codes and proper rooftop construction techniques. Overall, a properly built rooftop deck is a great way to fully utilize your home by taking advantage of additional space. 


    FAQs About Rooftop Decks

    Does a rooftop deck require special permitting?

    Yes, most areas require permits for rooftop structures. My experience has demonstrated that it is best to have complete approval for your rooftop deck to ensure compliance with local codes and regulations. Plan to gain authorization to ensure compliance with codes and regulations.


    How much weight can a roof support?

    How much weight a roof can support depends on the roof’s structure, components, spans, and age. I highly recommend having an engineer evaluate your roof’s ability to support weight.


    Should you hire a contractor to build a rooftop deck?

    Due to the highly specific knowledge needed for this type of project, I recommend hiring a trusted professional when building a rooftop deck.


    Editorial Contributors
    avatar for Nikki Stavile

    Nikki Stavile

    Nikki Stavile is a writer based in Tucson, Arizona. As an avid backpacker and passionate environmentalist, her work often focuses on sustainable movements at the personal and societal level.

    Learn More