75 lbs per square foot. Mine is 10' long, 19" wide. So that's about 15 square feet, which works out to about 1000 lbs total distributed load. As a 195lb guy, I can tell you that the platform flexes a little bit as I'm walking around on it, but not so you'd be concerned. It's plenty strong for working on, or holding a reasonable amount of material like roofing. I wouldn't stack piles of cement mix or shingles on it, but a sack or two should be no problem.