Home>Discussions>YARD & GARDEN>Decks, Patios, & Porches>Can a rooftop deck handle container plants?
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Can a rooftop deck handle container plants?

We have recently had a rooftop deck constructed on the third floor of our MN home, and since we have virtually no yard, are considering using some of the space to "go green," while still leaving plenty of room for entertaining. However, our trusted friends in the home improvement world have differing opinions.

The deck is 8x24, made of cedar, by a reputable contractor. It sits on the third floor on a nearly flat section of roof, above the enclosed living space on the 2nd floor and an open porch on the 1st floor. We have several lightweight pots we use for tomatoes, other vegetables and flowers outside. When filled with potting soil and plant material they weigh 25-30 pounds each. At about 15" in diameter we could put a row of about 15 of these on the deck with still ample space for sitting/entertaining.

When we told one friend about our plans, he warned us that the added weight would be much too dangerous if we used this many containers. When we mentioned this to another friend, he expressed that he thought one could fill the entire deck up with such container plants without a problem, as long as they are kept on stands to prevent moisture trapping underneath.

Can you help settle this for us? Thank you in advance!

A. Spruce
Re: Can a rooftop deck handle container plants?

It will completely depend on how the structure was built, what materials were used, etc., to be able to answer this question.

Being that you're in MN, I'd guess that the roof was designed to take a snow load, which means that you can probably load it up with as many planters as you like, HOWEVER, unless you've got the original plans and know for certain how the roof and supporting structure was built, I'd limit the number of planters to 5 or 6 at most, because you have to account for the entire load that the roof will take at any given moment, that is to say, the deck is already exerting weight, planters will add more, furniture will add more, people are going to add considerably more, especially the more people present.

You'll also want to consider whether or not you'll be removing the planters from the roof during the off season, because when they fill with rain, snow, and ice, they'll add a whole lot more weight than snow alone. Again, remember that you've already added a considerable load with just the deck itself.

Basically, what you're gambling is whether or not the roof is going to cave in, so the decisions you make now will go a long way towards whether you win or lose the bet.

Re: Can a rooftop deck handle container plants?

To answer this takes a deeper look. 3 stories of house is the limit of normal framing. The deck has already went beyond that by itself. You need to know whether the entire structure can safely take more, right down to the foundations. I'd want an engineer to be involved before going any further.


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