If you've been building for any length of time, you've probably used your share of construction adhesives. These synthetic bonding agents have become as familiar a sight as galvanized nails. They're used for joining everything from wood, metal, and concrete to gypsum board and rigid foam (see "Matching Mastic to the Job," next page). Adhesives make floors stiffer, minimize nail pops and squeaks, let you decrease the number of fasteners in finish materials, and double as a sealant. But while construction adhesives may be common, not all adhesives are appropriate for all situations. At the same time, some site conditions inhibit an adhesive's ability to do its job. Understanding how an adhesive
