Expert: Dan Griffin - 11/9/2007

Question
My son wants to install a heavy punching bag in the basement of my home which was built in 1985. He has a heavy duty piece of metal that will fit between 2 floor joists and it uses a 2 bolt/nut combination on both sides

so that holes would be drilled in the floor joists so this metal support bracket can be attached. It has a heavy duty eye bolt that the bag would attach to. The bag weighs about 100 lbs. My question is; are the joists able to support this bag? Any possibility for permanent damage?

Thanks, Steve

Answer
A few drilled holes about 1/2" diameter shouldn't hurt anything.  100 lbs as a concentrated load is nothing.  It is actually 50 pounds on each joist.

It would be ideal to drill the holes in the outside third of the span, not out in the middle, though for this I wouldn't worry.  It would also be best to drill the holes through the joists in the center (from top to bottom) rather than the very top or bottom.  JOists are in tension on the bottom and compression on the tops, the center is fairly neutral.