![]() I am a plans examiner and a Life Safety Code inspector, and I've seen a lot of stupid, dangerous things done by amateurs and professionals. Considering what's at stake, you don't need a catastrophic failure so using the services of a structural engineer is a matter of safety for you and anyone around the structure. Yes, you may be able to use the free design skills of your local supply store, but here in Florida, you don't get a permit for structural work like that without having a professional engineer (P.E.) submitting sealed plans for the structural calcs. I adapted a 'cherry-picker.' I'll post that up in a new thread. I even went as-far as-to buy a short-web I-beam with the idea to bolt it to the underside of the box beam at the ridge, but I discovered that between the I-beam girder, the trolley, and the rigging, I would lose precious headroom, and be unable to lift much over 3' in height onto the loft deck. If it was an I-beam girder I could use an overhead trolley on the lower surface flange of the beam, but due to the box construction, that was out. One concession I made to getting heavy things up & down to/from the loft, I thought about what would make an easy load-lifter? The roof ridge beam is also a 1/2" wall thickness box beam with plates welded to it for the ceiling joists. For access, I use an A-frame ladder, but since it's used for storage, it's not an everyday trip I make. ![]() The structure has no stairs to access the loft, not-even an attic 'pull-down' stairs. The beam is sandwiched on both sides by a 2" x10" (ripped to 8" to match the box beam dimension) wood beam to allow easier attachment of the loft floor joists, which are 2" x 8" & 18" o.c. The engineer did the calcs and gave us a front-of-the loft steel box beam, 1/2" wall thickness, 4" x 8" welded into steel flitch plates cast into the masonry side walls. We used a structural engineer, and I asked for a capacity capable of supporting the weight of multiple motorcycles. The garage is a nominal 20' x 22' & the loft is a nominal 13' x 22'. That's all we could afford to do, we kept the same roof instead of bumping it higher. So if you load a beam up to it's maximun design value that doesn't mean it's on the verge of breaking.I had built a loft which isn't full height above my two-car garage. In all cases, the higher the number the better.Safety factors are already built into the design values. But they don't come into play much in residential LVL design. The value for modulus of elacticity is generally what they advertise, which makes no sense to me.Then there are other values, like tension, compression PARALLEL to the grain, comperssion PERPENDICULAR to the grain, and shear. They're loosely related, but not the same. These 2 values are different - One is the strength, and on is for the elasticity. ![]() ![]() That tells how much bending stress a beam can handle before it breaks. There's also a vale called "Fb" - Some people call it "flexural stress", others call it "Extreme fiber bending". That tells how much a beam will deflect when a given amount of weight is put on it. Here are some examples:The number you mentioned, like "1.9" is the "modulus of elasticity". How much time have ya got ? Having trouble sleeping? Read this post just before going to bed for best results.(-:There are several different values assigned to lumber and beams.
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