Skinning Rack Between 2 Metal Trusses

[swampman]

Maybe I'm overthinking this scenario, but would love some reassurance.

First of all, my shop is a 36'x50' enclosed with a 16'x50 lean-to. Wood posts on 12.5' centers with metal trusses and 2x6 purlins & girts. I'm wanting to put a skinning rack in the lean-to portion to hang deer (nothing more than 300lbs.....probably like 100-200lbs mostly..). What I'm wanting to do is span a 6x6 on top of the metal lean-to trusses and position the load directly between two trusses. Anyone see an issue with this? Will the lean-to come crashing down if I try to hang something up there?

Photos below explain the construction better.

 

[tjdux]

I assume you will be fine. Those steel trusses are pretty soild i bet. Maybe be a little careful if theres a foot of snow on the roof but really even then still likely fine.

Let me ask you this, would you be worried if you or someone near 300 pounds was to walk on the roof for building or repair purposes? Not really any difference.

And lastly i hang stuff from my rafters all the time and they are just 2x6s. Nothing as beedy as what you have

Sent from my SM-G900V using Tapatalk

 

[gungatim]

you'll be fine. I hang and skin deer in my lean to all the time. and it's just 2x4 24" O.C. rafters with a piece of pipe spanning 2 of them and a ratchet pulley from a boat trailer.

 

[kbs2244]

So you are spanning 12 feet and expecting a max load of 300 pounds?

I would say a 6x6 will be way under stressed.

 

[blair683]

The 6"x6" is a little overkill I would say. A 12' 6"x6" is probably 120lbs by itself. I'd use a 4"x4" or 4"x6".

 

[Radix2]

Most people are looking at the wrong thing when thinking about applying odd loads to trusses.

The issue is the stability of the particular member you are loading as much as it is the actual load.

Trusses are made of small elements intended to be axially loaded and are quite fragile to side loads or bending loads. Trusses fall down and take buildings out when a component buckles and the problem cascades.

So the issue here is where exactly you are going to apply these 200-300lb loads to the truss members. Be cautious about bending any of the parts since they may have small sections intended for tension not bending.

This is very different from a 300lb guy on the roof. Notice that the roof purlins load the trusses at node points that prevent the top chords from bending, it is a far different thing to step between those purlins and perhaps bend or buckle a top chord element that is already in compression.

Maybe they are strong enough, maybe not, we can't tell from here...

 

[kbs2244]

Or you could just hang the deer directly from a truss.

 

[swampman]

Or you could just hang the deer directly from a truss.

I have thought about this, but would hang between to bays. My bays typically stay pretty full, so I would have to clear out 2 bays instead of one when a deer is killed.

 

[bad_idea]

The trusses are designed to support the weight from the purlins, the purlins support the weight of the roof (to include snow load). I am thinking it would be wiser to attach the pulley to the purlins. The easiest solution would be if you could pass a rope over one of the purlins. If there is no room for that, I would fab a bracket that bolts to a couple of the purlins. To keep the purlin from rolling or twisting, I would suggest you lag a couple 2x4s across the bottom of a couple purlins.

My thinking is the trusses are designed to support weight from above, not below. If the trusses are damaged at a they could lose their integrity and the ability to support your roof. The purlins on the other hand, are just a 2x6, nothing fancy there.

I am not an engineer, consider the cost of my advice when using it.