I have a cabin at the bottom of my garden (photos attached) and am thinking about hanging a punchbag from the roof beams. I absolutely do not want the structural integrity of my cabin compromised but i was wondering if a 100lb punch bag would hang safely (and be punched) from the beams in the picture? Or if not are there any small changes I can make to increase the structural stability of the beams.
The size of the beams are 115mm x 40mm x 5000mm and there are 2 screws in each roof board with a light felt roof on the exterior.
Best Answer
I would not.
That's a very lightly-constructed roof by modern standards. Those "beams" are little more than stiffeners--the roofing boards are carrying most of the load over their much shorter span. By themselves the beams are not up to the task of spanning that distance with any integrity.
In my judgement any load, even static, of 100 lbs. will result in sag or other effects, and the dynamic forces of a jiggling load of such weight could pull the beam loose from the deck boards. You're also likely to see spreading of the walls due to ridge sag since there are no rafter ties preventing such movement.