Rooftop Decks – Part I

Rooftop Decks – Learn about the most common roof water entry points (Part I)

The topic of rooftop decks is vast, and there’s not just a lot to discuss, but there’s also several variations of methodologies for constructing rooftop decks. In this part-one and part-two of the topic we will discuss some of the most common points of water entry and the general context of layout and mounting the structural load path of a rooftop deck.

Why Rooftop Decks Are Common In Washington DC?

To start though, it’s not a bad idea to talk about why rooftop decks are so common. Obviously, not every house in Washington DC has a rooftop deck but in the densely populated neighborhoods where the typical buildings are rowhomes or rowbuildings, it’s not uncommon to find rooftop decks.  Outdoor space is relatively limited in the densely compact populated urban areas such as Capitol Hill, Dupont Circle, and Georgetown.   A deck on the rooftop is a terrific way to get an outdoor space when the building lot (or parcel, in real estate terms) doesn’t allow for a backyard or significant front yard.  Outdoor space in the city is terrific, allows room for entertainment, and simple relaxation. An outdoor deck, for example, is a terrific place to have coffee and read the newspaper in the morning.

The picture below shows the overall layout of this deck in the context of the roof. Just on the right side of the deck you can see the demising wall and the parapet of that demising wall coming above the roof, approximately 8″ above the remainder of the horizontal (low slope) surface of the roof.

rooftop decks

The left side of the roof deck, in both the picture above and below, lines up next to the exterior wall and parapet of the building at the rear ell.

Poorly Constructed Rooftop Decks

roof water entry points poor construction

Several areas of the installation of the rooftop deck, particularly where the post passes through the roof membrane, look visually shoddy.   Notice that the 6×6 post at this mounting or bearing location appears to pass through the deck framing, beside but not on top of the structural parapet wall.  It’s generally more common for the deck to bear directly on top of the parapet wall because the roof parapets, where built from brick, are generally part of the structural load path of the building.

rooftop deck construction errors

Maintaining A Rooftop Deck

Smart proactive replacement, construction, upkeep and maintenance of low slope roof systems requires an enthusiastic interest and understanding of waterproofing principles and building science.   Here in Washington DC, historic and modern residential and commercial buildings are extremely expensive and the roof and related systems provide the shield that preserves the building. 

We encourage all of our clients, and all readers of this article and to our blog in general, to prioritize the value of quality construction and building maintenance, and develop a relationship with our company.  You can learn a lot more on our blog.  Feel free to check it out.  If you have questions about the roof and related systems of your building in Washington DC, contact us or fill out the webform below and drop us a line.  We will be in touch if we can help.

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