We are often asked, "what is the best tape to use with vapor retarders?" Essentially here are three tapes which are ideally used with vapor retarders.
For seaming, we have an excellent Vapor Tape, which has been formulated to be waterproof, and to stick extremely well to polyethylene vapor retarders. It also seals well around protrusions. It is a single sided tape that tear easily
Another frequently used tape is called Butyl Seal Tape. The Butyl tape has a reinforcement between double coated adhesive sides. This double-sided tape is used to attach vapor retarders to foundation walls, to protrusions, and ideally between overlapped layers of the vapor retarder as added insurance against penetration by water or water vapor (and many other types of vapors). This tape is permanently flexible, completely water-proof, and is incredibly sticky. It creates a permanent seal, which does not lessen over time.
Very few tapes are as ideally suited to this difficult application as these two tapes. First many tapes do not adhere well to polyethylene sheeting of any kind. Second, the introduction of water or water vapor on a long-term basis adversely affects many tapes. Many tapes and types of adhesives age over time, and basically deteriorate. The tapes we use are high performance tapes that have been tested and used in these applications for decades.