Take the 2-minute tour ×
Home Improvement Stack Exchange is a question and answer site for contractors and serious DIYers. It's 100% free, no registration required.

I'm planning to build a shelf in the garage, 22" deep and about 16' long. The back edge and one side will be supported by wall cleats, with 2x3s under the other edges. I'd like to support the front edge using steel cable from eye bolts in the shelf to eye bolts in the ceiling (truss framed) spaced every four feet other than the edge against the wall. (I like the idea of using cables because I think they'll create less obstruction when getting bins on or off the shelf.)

This shelf will hold about 16 of the large plastic totes, and I'd assume they'll be pretty full and heavy. I want to make this nice and sturdy, but I don't really have any sense of what size bolts and cable would be reasonable. I also want to make sure I'm not compromising the roof trusses with whatever I'm screwing into them or bolting through them. Any suggestions on sizes or attachment methods?

share|improve this question
1  
Is the shelf system running parallel or perpendicular to the trusses? If parallel, I'm thinking that's way too much of a load on the truss. –  DA01 Apr 8 '13 at 3:31
    
@DA01 trusses are perpendicular so each cable would attach to a different truss –  Brad Mace Apr 8 '13 at 4:32
    
That's definitely a better scenario. The trouble with roofing trusses is that they're really designed to hold up just the roof and some nominal amount above and beyond that. This is just me, but I'd probably opt for a solution that uses the concrete slab as the support...perhaps using iron pipes rather than cable. –  DA01 Apr 8 '13 at 19:20
add comment

1 Answer 1

up vote 7 down vote accepted

Shelf construction

If the shelf has its front open edge positioned such that at each four feet the cable would go up to a separate roof truss than I think that you have a workable system. Make sure that your 2x3's under the outer shelf edges are placed to that the nominal "3" inch dimension is vertical.

Hardware

Note that the lowest cost eyebolts, known as the "bent type eye bolt" are generally not recommended for lift and continuous tension applications. For this application it may be suggested to search out the drop forged type eye bolts as shown on the right below. These will cost more but they are actually specified for "lift" type applications.

bent eye bolt drop-forged eye bolt

If you do use the bent type, orient them so that the split end of the eye is up, as show above. Definitely use through-bolts rather than any type of screw-in eye.

eye screw

I would use 5/16" diameter eye bolts or larger.

Connection points

attachment points

Put the upper end of the cable through a threaded eye bolt that goes all the way through the side of the rafter truss and is secured in the far side with a washer and nut. Avoid the use of a screw eye type fastener. The eye bolt should be attached to the upper rafter part of the truss instead of the lower cross tie. When drilling the hole for the eye bolt position it in the upper part of the rafter as opposed to the lower portion.

Put the bottom end of the cable through an eye bolt that is long enough to go through the shelf material and the 2x3 and secure on the bottom with a washer and a nut.

Note that the orientation of the cable clamps is important, and it is always advisable to use two cable clamps for securing the cable.

Cable sizing

The size of cable is really dependent on the amount of load that you expect for the shelf. I would think that 3/16" diameter cable would be adequate for this application. The chart below will help to explain why I recommended 3/16" (assuming you use the 1x19 type of "stainless steel aircraft cable").

enter image description here

share|improve this answer
    
I may be wrong, but I thought I recall learning a long time ago that for hanging, lag bolts have much stronger holding power than through-bolts. –  DA01 Apr 8 '13 at 4:40
    
ah, I misread your answer. I see that these would be installed on the rafter part, so not entirely perpendicular. Scratch my previous comment, then! ;) –  DA01 Apr 8 '13 at 4:59
    
So the top bolts would installed horizontally? Never occurred to me to attach to the upper truss member, but I see why that would be stronger. In my case the ceiling is already drywalled, so I'd have to find some sort of grommet for where the cables pass through the ceiling. Does it matter whether I use ferrules like this or the U-bolt style clamps? –  Brad Mace Apr 8 '13 at 5:14
    
Also, I guessing I should use turnbuckles since I probably won't get them all exactly the right length to start with. Anything to be aware of there? –  Brad Mace Apr 8 '13 at 5:15
1  
@BradMace - I see no need for turnbuckles. With the small diameter cable I recommended it should be easy to get the cable pulled through the eye bolts and clamped to the correct length. –  Michael Karas Apr 8 '13 at 5:31
show 3 more comments

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.