Sealing joints in polyethylene ground cover
Depending on the type of ground cover you use, the lapped joints can be either sealed or taped. Acoustical sealant has proven to bond well to plastics. Butyl rubber or butyl acrylic caulks also work well for bonding plastic. You may need to test your tape or sealant bond for your particular choice of ground cover materials.
For more information, see Air-Sealing Tapes and Gaskets.