Will my ceiling handle this?

[Angelfire]

Hiya Folks,
Not a structural engineer by any means but I know that my trusses are really only designed for drywall and not much else. Attached is a detail of the trusses I have over my garage.

I've just bought another Jeep and want to lift the hard top off and hang from the ceiling if possible using a simple hoist system. The hard top weighs about 140lbs. I was thinking of spanning 3-4 joists using 2x lumber and mounting my hoist system to this. I would need to lag this lumber to the bottom of the chords as I have no access to above. I currently have 1/2" drywall up there along with Roxul insulation. Additionally, I've put a solar array on the roof (not sure of weights there but the company that did the install indicated it was well up for it).

So given the weight of the top, lumber, pulleys, etc... (figure around 160lbs), would this work? If not, I'll have to look at another option for removal and storage of the top. Appreciate any of you structural folks' help!
Cheers.

 

[xyster101]

That is not a lot of weight and should be fine. A 2x4 joist will hold the weight of a 200lb person in one spot. Those will hold that weight easily spread over a few of them.

 

[Angelfire]

Thank you. I kind of figured as much but really wanted some assurance as I don't want to hang the thing up and have it come crashing down.

 

[RedSS454]

I don’t have trusses like you, just standard roof joists. When i had my Cobra kit, i used two winches mounted to the joists to raise the body (one front and one rear). Tripled up the 2x6’s and lagged them in. They didn’t run to the top plate, but higher on the peak. Worked very well. Body weighed probably 200 or so pounds.

 

[Bigblockyeti]

You definitely won't have anything crashing down but invariably you will have some deflection. If you have the ability to get on top of the roof and walk around you should be able to feel when you're on and when you're off one of the trusses assuming they are 24" O.C. Standing directly over one at the approximate location you want to install one of your lifting pulleys(?) bounce a little on the balls of your feet to feel if there's much movement beneath you. I got a little more science doing the same directly above the steel beam that spanned my garage (26') with my brother looking at a dial indicator I had rigged to a step ladder. Jumping hard I could get just under 0.375" while carrying a pack with enough weight to make my static load right at 250lb. yielded a deflection of just under 0.060". Making sure each of the two transversing 2x4's lands on at least four trusses should give a minimal level of deflection.

 

[bczygan]

Yes.

 

[nitroracer20]

You should have no problems with that light loading!

I have a chain hoist off one of my rafters. I trippled sistered my rafters in this location, transfering load through top plate, and onto the wall studs - also tripple sistered.

Never noticed any rock cracking or nail pops. No creaking. Loaded up to 500+ lbs.

Youll use the hoist more than you think!

 

[Marctrees]

Better than old fashioned cheap lags - Simpson Strong Drive or GRK RSS or similar.

Marc