Hoist from ceiling truss - what do you think?

[angler1]

Pics attached.

Okay, the installation is done, but before playing with it, I would like to get some thoughts on my engineering. I know most will freak out with a big NO but want some thoughts on just how bad you think this is. I attached unistrut to the ceiling and side walls and added a hoist, mainly to lift my bike rack (up the side wall). The garage is attached with just a roof over it, so it is a 2x4 truss ceiling. AND, my uni-strut runs in the same direction as a truss, so I could not span trusses, and attached only to a single truss. Yeah, I know.

The bike rack will hold 3 electric bikes. Total weight with the rack might be 350lbs. I thought I'd trolly the hoist with the ceiling unistrut piece just in case I ever need to pick up a lawn mower or something further out from the side wall. Maybe 100lbs max. I did add a board about middle of the unistrut ceiling track tided into the roof rafter with carriage bolts in the attic.

Since my main load 350lbs will be up a side support wall, do you think I have a problem here?

Then, further from the side wall, will my carriage bolted board assist some weight?

Generally, what are your thoughts on this before I put more bikes on the rack.

 

[couch67]

time will tell. Usually not a great idea to stress a single truss as you know. But... the weights you are talking about arent crazy.

 

[Old tool guy]

How did you attach to the truss? I would have run some kind of strap over the bottom chord, rather than run screws into the bottom of the truss.

 

[angler1]

How did you attach to the truss? I would have run some kind of strap over the bottom chord, rather than run screws into the bottom of the truss.

Yeah, thought about that. Also thought about all-thread to the roof rafters. But just pre-drilled and ran 1/4 hex screws, adding more holders than originally planned.

 

[djbmw]

You could use the mathematical lever equation with the "pivot" point being all the way to one side to see how much weight is being supppeted on the truss vs the metal brace. Having said that, the metal brace isnt doing to much at the very end and, assuming the whole load is 350lb, likely there's less than 325lb on the truss.

 

[angler1]

You could use the mathematical lever equation with the "pivot" point being all the way to one side to see how much weight is being supppeted on the truss vs the metal brace. Having said that, the metal brace isnt doing to much at the very end and, assuming the whole load is 350lb, likely there's less than 325lb on the truss.

Didn't think about leverage, but that's interesting. It likely is helping amplify strength at the wall side, since it would cantilever the far-left side up.

 

[angler1]

What about my board carriage bolted to the roof rafter? I don't know the physics/engineering of truss roof design too well. If I ever venture to pick up something heavier further into the room, is this adding a lot of help, no help, or what?

 

[Jeff Ivers]

My first thought when I saw this was "does he have cats?" My second thought was he is showing pictures of a completed task he is proud of.

Many years ago, I was into model railroading for a time in a very small house where my parents lived. We eventually came up with the idea of suspending a 4x8 sheet of plywood from the ceiling of the garage with ropes and pulleys for a train table that could be lowered onto a pair of sawhorses. We had noticed that the cats occasionally climbed the attic access ladder on one wall of that garage. The train table worked great and still left room for putting the car in the garage for months - until one day the cat's curiosity got the better of him and he leaped from the attic ladder to the train table, setting it to swaying while in the up position. Fortunately the car was outside, as the whole assembly came crashing down.

You said you had no choice but to follow the one joist. Why? If it were me, I would have a 2x4 in the attic running perpendicular to your strut and spanning at least 3 joists. A piece of 5/16 all thread would run through the strut mount and up thru the 2x4 where it would be capped by a large fender washer and double nuts. I would have done this near the wall and out just far enough to clear the items you are suspending. The strut would parallel the joist but be offset so the all-thread would not go through any joist. You could have used a lot less strut, fewer strut mounts and not had any penetrations of a joist.

Your installation certainly looks nice and may hold up just fine. Based on my experience, I would not allow cats in that garage.

 

[kaymccampbell]

If you sistered a full length 2x8 to the ceiling joist element of the truss, gluing the two together and screwing them every 6-8" , I'd feel comfortable.

 

[ratdoggy]

I just put a 2X4 across a couple trusses. Bolted to that. But my bikes aren't 350 lbs.

 

[angler1]

My first thought when I saw this was "does he have cats?" My second thought was he is showing pictures of a completed task he is proud of.

Many years ago, I was into model railroading for a time in a very small house where my parents lived. We eventually came up with the idea of suspending a 4x8 sheet of plywood from the ceiling of the garage with ropes and pulleys for a train table that could be lowered onto a pair of sawhorses. We had noticed that the cats occasionally climbed the attic access ladder on one wall of that garage. The train table worked great and still left room for putting the car in the garage for months - until one day the cat's curiosity got the better of him and he leaped from the attic ladder to the train table, setting it to swaying while in the up position. Fortunately the car was outside, as the whole assembly came crashing down.

You said you had no choice but to follow the one joist. Why? If it were me, I would have a 2x4 in the attic running perpendicular to your strut and spanning at least 3 joists. A piece of 5/16 all thread would run through the strut mount and up thru the 2x4 where it would be capped by a large fender washer and double nuts. I would have done this near the wall and out just far enough to clear the items you are suspending. The strut would parallel the joist but be offset so the all-thread would not go through any joist. You could have used a lot less strut, fewer strut mounts and not had any penetrations of a joist.

Your installation certainly looks nice and may hold up just fine. Based on my experience, I would not allow cats in that garage.

Dog, but No cats! This project nucleated from wife's idea of cleaning out the garage and organizing things better. Of course, I had to get a little goofy and add a new hoist idea to lift the bikes up. So, after a couple hundred $ in hoist motor, trollies, hardware, etc., I starting looking for the shortest path to a decent end to this thing. ....so I could get back to cleaning out the freaken garage! I didn't plan to spend hours in the hot attic but was up there several times of course, mapping things out, and thinking about exactly what you suggest, as well as other ideas. Knowing my main load would be on an outside wall, I did this as a quicker end. But I am worried, and hence why I thought I'd get some more mechanical minds commenting on it. You guys are awesome, thank you. I did think that I could do some things in the attic to beef it up later...if I wanted more strength further out from the wall. Laminating another truss on this one, attaching cross beams, and crossing more trusses maybe. But I'll probably blow that off until I have the hot idea of pulling an engine or something.

 

[NUTTSGT]

Like a couple above, I would have spanned the trusses with something, I would have used a 2x6, and through bolted to it.

Just keep and eye on yours to see how it's doing.

I do like the idea of the electric hoist though.

 

[PopcornSutton]

I had 6 deer hung up from the bottom cord one time. No problems.

 

[carlaisle]

We don't have the plans for your trusses, but a truss of that type in that application would typically be engineered to support a 5 pound per square foot dead load from the bottom chord. From your attic picture you appear to have 24" spacing, so that works out to 10 pounds of dead load per linear foot from the bottom chord. It was not designed to support any live load, which is what your bike rack represents. It was also not designed to support any kind of point load, least of all from the bottom chord.

About your "carriage bolted board": the bottom chord of your truss only has an area of 5.25". How many holes did you drill?

A vastly superior method would be to mount the winch to structure inside the wall so no additional weight or other unanticipated stress is imparted to the truss. This method would transfer 100% of the weight directly to the ground so your only material concern is how well you attach the winch to the structure.

 

[Old tool guy]

A vastly superior method would be to …

… build a gantry crane … but that’s not going to happen.

 

[rsanter]

Personally I would not do that.
You need to span several trusses.

Go get some unistrut.
Go into the attic and attach the unistrut to the top of the bottom cord of the trusses and span at leas three trusses (5 is better) to distribute the load better.
After that I don’t think I would be concerned

 

[Old tool guy]

Go get some unistrut.

Do you think unistrut would be stiff enough to spread the load? I think it would work to distribute it over 2 adjacent trusses, but i think a 2x8 on edge would be better for multiple trusses.

 

[rsanter]

Do you think unistrut would be stiff enough to spread the load? I think it would work to distribute it over 2 adjacent trusses, but i think a 2x8 on edge would be better for multiple trusses.

Either will work. The 2-8 using the ties can work well

 

[Beamer]

Reminds me of a job I had after a guy bought a house and since his jacked up truck didn't fit under the steel beam crossing the garage ceiling he took to cutting out half of it's depth, the length as needed to span the truck width..........and THEN he called.

 

[mike93lx]

I would definitely not have all that on a single truss.