I'm looking for some advice on building a gym on my flat roof and would appreciate any insights or experiences you could share. (Note I am NOT an engineer and will NOT be executing this without professional advice and contracting.)

Here's the situation:

  • The roof is flat and has a modified bitumen layer.
  • There's a “doghouse” on the roof, and it is on an otherwise unfinished portion of the roof.
  • Live Load limit of 100 PSF
  • Dead Load limit of 40 PSF (I think. Blueprints show “DL= 15 PSF + 25 PSF (pavers)”)

I plan to set up a gym that includes a platform, power rack, barbell, and weights. I'm concerned about the load capacity and safety aspects. I'm also considering if hanging weights in the doghouse to decrease the direct dead load on the roof will help.

Has anyone done something similar? Is it feasible to support this kind of gym setup on a flat roof? Any advice on how to safely distribute the weight or additional considerations I should be aware of would be greatly appreciated.

Thanks in advance!

  • There are no pavers in place at present?
    – Ecnerwal
    Commented May 27 at 20:15
  • Correct — one side of the roof has pavers, but the side at issue here does not have pavers.
    – Andrew
    Commented May 27 at 21:48
  • 3
    My advice, don't do it. Too much weight. too many possibilities to damage the roof , then damage the rest of your home.
    – RMDman
    Commented May 27 at 23:25
  • Wooden roof? Concrete?
    – Huesmann
    Commented May 28 at 15:37
  • Wooden roof. 16” open web trusses, 3/4in plywood on top
    – Andrew
    Commented May 29 at 14:16

1 Answer 1


You'll probably have to reinforce the walls and roof if you plan on having an outdoor gym up there, particularly if you have heavy gym equipment. Creating a gym on the flat roof of a building is definitely doable, in fact, almost any type of outdoor facility is possible on a flat roof if it's engineered and constructed to take the weight. There's even some rooftop swimming pools and trees planted on roofs! Also, many people engage in gardening on flat roofs.

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