I can't believe some of the posts that have actually dropped their jacks down on pavement with out any kind of board or bought jack pads! Incredible. I "always" put boards down no matter the surface beneath my rig. I carry a variety of sizes and thicknesses so I can match up un-even sites. If its pouring rain out when we are leaving our home for a weekend get away I'll throw a couple more lengths of rafter sandwich board in the basement just for insurance of a wet soft site. All scrap lumber cuts picked up from new home build sites, free.