Hi, Russ, Lowe's had what amounted to a plastic L shaped piece that I used for spacers. I ran the corrugated material perpendicular to the joists, so the spacers just attached to the joist. I just used a piece of string to set the slope and ran the slope about 1/4" per foot. Good luck with your project. -Josiah
Josiah, I saw your post about the under deck drainage system you built. What did you use as spacers under your joists? Do you have any pics? Would you do anything different? I was just getting ready to build the same sort of system for my deck and happy to find your post I welcome any insight you have. Thanks.