I live in a three story apartment. I have a patio which also has a storage off of it. The actual patio is 8 X 10 and made from decking boards. However the exterior corner is supported by a 4 X 4 for three stories. How much weight could that possibly hold? I am a large man and could 3 or 4 guests cause an unsafe situation?

About how much weight could my patio support with one corner being just 4 X 4? Just looking for safe options. I also have plants on my patio which could take up about 200 LBS.

  • I do not like the numbers that come out of this column calculator when I use a 20 foot (x and y unbraced) 4x4". courses.cit.cornell.edu/arch264/calculators/example7.1/… Knowing more about the geometry and bracing as you do, you may come up with more reassuring numbers. Apr 6, 2015 at 19:44
  • Usual situation would be braced every 8-10 feet (by the porch/patio below) in multistory applications. But a picture would help, some.
    – Ecnerwal
    Apr 6, 2015 at 22:11

1 Answer 1


This really needs to be looked at by a structural engineer, or similar qualified person, to give you a load bearing range. To calculate the load one would need to factor in the size of the wood, the type of the wood, condition of the wood (rot, ...) the overall weight of the structure, and how it is secured to the structure. I can speak from experience that balconies do collapse from overloading and poor maintenance. Where I live they had one collapse about 10 years ago and many got hurt. The codes had to be updated and new rules were made for enforcing them.

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