I own two of these footprints; The UL1 and...
I own two of these footprints; The UL1 and the UL2. Both are so lose fitting that they fall off if I pick up these tents to repostion them. WHY do these footprints fit this way? Is there a reason for this? For the record, the UL1 footprint weighs 5.5oz, and the UL2 weighs 6.32oz.
I don't own any of the UL series but the Big Agnes, (and Eureka), tents I've owned with factory footprints always had footprints that were just glorified, expensive, cut to size, rip stop with grommets or straps at the corners. They never fit tight. That being said, you might give some plastic carabiners or S biners a try to hook the corners. Should work for 'ya and if not, they have a ton of uses and you won't regret having them around. Good Luck!
I have both the ul2 and the ul4. What I do to keep the footprint from always falling off is I put the foot print grommet on the pole end first, then the tent. That way, the footprint, even though loose, is held on by the tent. I don't know why they fit loose. Generally footprints are slightly smaller than the tent dimensions so water doesn't flow and pool underneath.