Lifting from ceiling

The flatness of the roof beam angles make for quite weak strength against whatever is supported at the middle of them. Like said above, I would not try to lift more than 100 pounds as is, and would watch it carefully for signs of problems. Like also said above, vertical braces like 4x6's close in to what you are lifting, can lift very heavy amounts. It is useful to create basically a gantry crane as narrow as what you are lifting, with the existing structure just helping to keep it all vertical. The setup can be cobbled together, just be aware of the forces trying to spring the lumber in compression and avoiding the entire cobbled setup racking into a parallelogram under load. It would not be crazy to lift at least a ton with such a setup, depending on understanding the load paths and accounting for them.
 
You could use a couple of Acrow jacks bearing on shaped timber blocks placed underneath the purlins to transfer some of the load to the ground. As Bob says above, the flatness of the roof means that you are trying to pull the ridge down, which will force the walls apart. In medieval times they would have put flying butresses outside the building, you could do this, but it would probably be cheaper to buy a gantry crane. i too have an RSJ lifting beam, and it has saved my back and removed some very heavy engines as well!
Phil
 
Do a compression test. Hang a plumb bob from the peak so it's 1" off the floor, then lift something heavy to see what it takes to make it touch the floor. Use good judgement, maybe that will give you some factors to figure.
 
A couple hundred pounds lift sure can be handy but that chain hoist will likely do more than the building is rated. And there lies the problem, you have no built in safety factor and no ability to limit the load to only a couple hundred pounds. The failure mode is a roof /beam heading for you and the floor. Where do u stand for safety? If your gantry crane, engine hoist or tractor front end loader fails, you probably won't be under it when goes to ground and your roof will still be safely suspended above you.
 
A roof frame is always capable of supporting two men working on the roof...the frame looks like 5x3 Hot rolled beam,..I put a lifting beam in a similar frame by installing a length of similar section lengthwise in the peaks of the frame .,then using a block on a runner.In this case the chain block /beam is always supported by some combination of all the roof frame........but would need a complex stressing calculation to assess point load on one element.......which is what computers do very well.
 
I have lifted a lathe and a mill from the ceiling. The joists are 10" engineered joists. I laid a 8'-0" 4x6 across the joists in the loft. A 7/8" bolt, threaded connector and an eye bolt came thru the 4x6. A 1/2 ton come-a-long and nylon straps for the lift. This set up worked but was a PITA.
This was done about 20 years ago. Last month I had to lift the lathe 8" or so to remove the bottom studs and nuts on the motor mount frame.
I bought a 2 ton shop crane and made this job easy.
mike
 
Stonebriar said:
Gantry crane is much cheaper than erecting a new building.
Click to expand...
I agree.

What do you intend to move? If it's large enough to consider using a ceiling crane, it's probably going to be too much load for that building. Hard to tell from the photo, but it looks like the building has a relatively shallow roof pitch. That's not good for a ceiling crane. But it also looks like it is large enough in floor space and vertical clearance to accommodate a gantry crane. Definitely a lot less risk involved. Also, depending on what you're trying to move, you can accomplish a whole lot with an engine hoist and pallet jack - especially if you've got the floor area. I've moved plenty of pieces of equipment that way.

Regards,
Terry
 
My metal building is of the ridged frame construction so more capable. but Where I live a 30#/ sq. ft. snow load is figured. So the roof framing is designed for that + a safety factor. Using the distributed nature of the loading design you can figure what just the snow load force would be at any point. You can't count wind load for roof downward force. Ask the city what design load is required for a permit. I some cases the design limitation is based on sag, not failure point. The kind of frame in your building will have the roof WF beam designed as a simple beam. The fact that it is two parts bolted together and on a slope doesn't affect the design. No increase or decrease in strength results from the shallow V since there is no bottom cord. The WF building columns were most likely considered as pin connections for design meaning no outward force resistance need be considered. For practical purposes the pry on the foundation bolts would have to be the resistance ability, not enough to count. If you are really into it, look up a copy of the steel structures hand book. There are tables that show what design load can be used for each size of beam. You need to accurately measure your beam to look it up. To be on the safe side use the lowest strength steel for your calculations. Somewhere in my mess I've still got my steel design book from taking the classes in structural design. A university library will have a current copy.
 
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