Adhesives are used with wood for the following main applications:
- laminating or surface gluing: used, for example, for wood veneer or plastic laminate; not so often found in external situations, except for non-slip strips used on steps;
- frame assembly: joints with glue lines, which provide close contact between surfaces; conventional, machine-made, glued wood joints are close contact;
- loose fitting or open joints: may require gap filling owing to uneven surfaces; and
- structural joints: critical to a structure, they need to have good “creep” resistance (i.e. the ability to resist distortion over a period of time).
Adhesives tend to be stronger than many lower-density lumbers, (e.g. below the density of beech, which is 40–50 lbs/ft ...