I have an attached 3 car garage with sheet rocked house walls & ceiling. The rest is bare studs. Wall studs were added to separate the 3rd bay from the other 2, after the house was finished (no footing, just built on top of garage floor.) I am now building a workshop in that 3rd bay & want a loft for spare lumber in part of it, since I have over 10.5' ceiling. The workshop is 12' x 25'. I would like the loft to be open-ended to get lumber in & out. My thought was to make the loft about 12' wide by 10' long, with about half-inch ply floor. The 12' dimension would be from the added stud wall to the outside wall of the 3rd bay. The plan is to add a 10' long cleat along the added wall & along the outside wall of 3rd bay, AFTER sheet rock is up/finished on those walls. Then, saddle the loft joists 24" on center on top of the cleats (unless you suggest a better way), reaching across the 12' width of the shop. Would 2 x 6 joists be enough to support say 1500-2000 lbs? Is there a formula for figuring what spans to use? Would I need braces between the joists, to keep them from twisting/collapsing under load? Also, this is a newer house built with roof trusses instead of rafters, so I could suspend the loft joists from the ceiling. Do you think that would be advisable? Thanks, Rob in Wichita, KS.

I would be real careful suspending any considerable weight from the roof rafters. Truses are built with"stressed Lumber" They are trussed with a camber in them for diflection outward for support for shingles and snowlaods. You should nail your band lumber right against the exposed wall first then drywall above and below it. To run my joist , joist hangers is quick and easy. Now there is a "live load "floor and a "dead load" you have a dead load ( storage) If sounds like you are using 2x6 at 24o.c. to either save money or head height. The min o.c. for basic joist is 16 o.c. Now you are very undersized in joist thickness. Standard would be a 2x10 16 oc That's the safest. You say approx 1600 lb 1/2 ply. Is the load spread out evenly. Your outside joist needs to be doubled up and at least a 2x10 even though the joist are smaller in height. Braces between the joist is fine but that not the big issue here. Put 2x10 joist in st 16.oc or 2x8 12"o.c. see how this steps down for load. 2x6 is a no no at 24"oc. You need to give also more thought on the band with that's not supported like the back of the joist that's nailed into the other two walls. This band needs to be doubled up to carry the load from corner and a post at the one corner is s a must and not the rafters. If you only use one post. That outside band should be doubled 2x10 to carry the joist. The joist can be smaller but the bad carrys half of the loft floor and weight. Now anthor way is to do an angled loft from corner to corner. This works great in my shop and has no posts. To do that you do need to order or get longer band lumber. i.e. 2x12 20 or 20 feet long and double that up. St the ends put a post to carry the load not just the nails that are nailed in the side to the other bands that are against the stud walls. Basic rule of thumb 200 lb dead load for 2x10 16oc 3/4 sheetinf. The thicker sheeting also transfers the load to its sister joist so they can help carry the load. I am not an engineer nut I have been building for 28 years. Happy holidays.

My name is George Matos from Winnipeg Manitoba Canada. I am looking to build a similar structure in my garage for a dead load. Thank you for the response you provided as it does help me. Is there any chance of pictures you can provide as well.

Welcome GMATOS

This post is 4 years old. If u post your question in a new post, u will get the answers u need.

Good luck

Chuck

Thanks for responding, I will do that.