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During installation of the 4' x 8' SafeRacks, I discovered that the ceiling joists in my garage are 2x4 trusses, instead of solid joists. Unfortunately, the product comes with 3" lag bolts, and after consulting with their customer service, they insist that I need at least 2" of solid wood penetration (the ceiling truss would only provide 1.5").

Would it be acceptable to substitute the 3" lag bolt with 2x 2" lag bolts per location? The product is rated to hold 600lb, and I doubt I would utilize the full weight capacity. At the same time, I don't want to put my family at any safety risks.

EDIT: Thank you for your comments so far. I really appreciate your responses! Here is a picture of my garage ceiling, prior to drywall being installed.

8/27 EDIT: Given the expert advice here, I have decided to return the racks. I'm going to look for shelving that are mounted on the sidewalls. I'm very glad that I found this site. Thank you - you guys rock!

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    How long is the total span of the joists, and how far away from the nearest support are you planning to hang the racks? I would be less worried about the lag bolts than about the joist itself; a 2x4 on its flat side has considerably less load capacity than on its edge. The danger here is not just the rack falling down, but part of the structure of the garage itself. – gregmac Aug 26 '15 at 6:47
  • Do you have access to the space above the ceiling? – Tester101 Aug 26 '15 at 10:53
  • @gregmac I think your comment should be an answer. Comments don't last forever, and yours is important information. – bib Aug 26 '15 at 11:39
  • I'm curious as to how the rest of the roof was built. Flat 2xs seems like a huge red flag. – DA01 Aug 26 '15 at 17:02
  • I just viewed your photo. you have trusses for roof framing. Trusses shouldn't be modified unless you are sure of how it affects the integrity of the roof system. Trusses are engineered and designed for specific and unique tolerances. I'd be wary of increasing the bearing load that it was designed for. – ojait Aug 26 '15 at 17:45
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2x's laying flat as opposed to on edge are going to bend or break when weight is suspended from it over time. The longer the board the faster it will compress or fail. To remedy this problem you must add support to the existing framing members. I think the simplest way is to install additional 2 x 4's (on edge) attached against the edge of the original 2 x 4's. It should have a "L" shape profile. You didn't mention the span of the rafters, but you may consider adding webbing above the platform. All this is are lengths of 2 x 4 attached to the platform joists at one end and the other to the mating roof rafter above. This is probably over kill, but still another way to prevent a failure.

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    Better yet, depending on the span, use 2x6's or 2x8's. – Les Aug 26 '15 at 15:28
  • From the photo, OP has trusses, not a simple 2x4. It was a red flag to me as well until I realized what the OP was describing. – BMitch Aug 26 '15 at 17:49

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