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This board with its edge facing down. Can I hang and use a 100lb punching bag from it without breaking any part of the ceiling?

How do you think I should do it? Should I put a strong metal bracket over the top and bolt the hook to that?

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  • Don't do this. After 15 minutes of use, the board had a long crack down it. Some of the attached members also cracked. For an extra $100 you can buy a stand to hang the bag from, much safer for your home.
    – user193661
    Commented Mar 13, 2016 at 21:31

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I wouldn't call that a joist, I'd call that a tie. A joist is something supporting a floor, designed to take vertical loads in bending. A tie is something designed to take tension loads, in this case that tie is there to stop the roof spreading sideways at its base.

Now, just because it is a tie doesn't mean it can't also take some vertical load. In fact, it looks like there may be a vertical member running from the roof ridge down to this tie, which in all likelihood does bring some vertical load down onto the member.

So the important question is "What spare capacity is there for vertical loading on this member?". If you put bending load into a member, you reduce its capacity for axial force. So in order to answer, we'd need to know:

  • the member size (breadth, depth and length; easy for you to measure)
  • the wood type
  • the current axial load on the member (very difficult without knowing the whole roof structure)
  • the current vertical load on the member (very difficult without knowing the whole roof structure) and its position on the member

We really can't answer all of this over the internet. You could employ a structural engineer if you want, though this might be overkill. But, never fear, I have a solution!

I'd be happy to expect the walls to be able to take an extra 100lbs. So what we want to do is, instead of risking overloading the tie and destroying your roof, put in a new joist specifically to take your punching bag. You can take a flyer and just buy one if you want, or you can try and do some engineering calculations for it, to make sure you get a big enough one. There are a few questions on here about joist design, if you search for them.

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  • I think it could hold the weight. If I grabbed onto the board and did pullups on it letting my weight hang, and nothing happened, would that be a good enough test?
    – user193661
    Commented Feb 12, 2016 at 12:09
  • What you suggested about putting in a new piece of wood. That would be ~30-40ft I think. Would I need to pay a truck to bring it in?
    – user193661
    Commented Feb 12, 2016 at 13:03
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    @user193661 - Your local builders merchant will probably deliver. I'd expect to pay something like £25 for a bulky delivery from my merchant. Not particularly cost effective for a single joist.
    – AndyT
    Commented Feb 12, 2016 at 14:48
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    With regards to putting your own body weight on it: that would be a reasonable test, but do be warned that timber creeps, i.e. the longer a load is left on it, the more it deflects. (This is talking in a timescale of years. If you were to hang the bag, punch it a few times, then put the bag back on the floor until tomorrow, then your own bodyweight would be a reasonable test.) It's pretty obvious, but just in case: don't test it with your body weight if you're worried about a) the whole thing falling on you, or b) the cost of repair, if it turns out it can't take your weight.
    – AndyT
    Commented Feb 12, 2016 at 14:49

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