We use the heavy shelving material you can get at Lowe's or Home Depot. We just use the best masking tape you can buy (3M Blue) at the top so that it will come back up without leaving a residue or coming apart. We replace the tape every so often and vacuum stairs off.
Works for now.
Larry, Stephanie Park City, Utah
2017 31SL King, 8K axles, Disc Brakes,17.5 Goodyear H tires,BU Camera,5.5 Onan, Heated HT pads, Two Uniguard Awnings, Slide Toppers, 2000w PSW inverter