rsj, like an i beam? More beams are more stronger, no question about that....but not having beams is pretty nice
I know there is plenty of wood to hold normal room weight. I was a lityle worried about the joints on the verticle wall pieces because they are in basically pure tension which is the opposite of standard construction...i hate working with materials I can't weld. The nsol plates were smaller than i wanted but were in stock so i settled....then worried which is what led to the sheeting on the corners, I feel pretty good about it now.
If I were going to try and store engines and such up there I'd still be worried, but I'm just planning light bulky stuff....i can't imagine ever having more than a few thousand lbs total up there and I'm pretty sure 100lbs/sqft (plus another 30lb/sqft snow loading) would be fine, and that's 18000 lbs, so I think I could put a couple cars up there and they'd stay. Trusses are very strong, the whole roof becomes a beam, so it's like a 9ft tall wood i-beam, it will hold a lot of weight....if the not welded joints stay together.