I installed a overhead storage shelf made by Hyloft (see item here:
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to make sure the corners were parallel to one another. They suggested hanging one then measure off it to get to line up. My brother and I struggled a bit to do that. We got it done, but the hardest part I thought was how do you hang something parallel in middle of a garage/workshop ceiling? No reference points within 5 feet of any one direction.We did it with careful measuring. I thought later we should have just made a template out of cardboard and just done it that way. The brackets have to line up on a joist. The job was way too long for what should have been a 20 minute deal.
Like to do it again, buy since my brother is leaving to go home this weekend, it will have to be a solo effort.
MJ