Structural glue laminated timber is made from three main types of adhesives. These are:
- Resorcinol formaldehyde (R);
- Phenol/Resorcinol formaldehyde (P/R) and
- Casein
Casein adhesives are suitable for "interior" service grade laminated timber members that are permanently located in dry, indoor environments.
Resorcinol and Phenol/Resorcinol formaldehyde adhesives are the most common glues used for Australian conditions. They provide bonds meeting the requirements for "exterior" service grade and resist weathering, microorganisms, cold and hot conditions and aggressive chemical vapours.
Reference: Timber Datafile P8 – Glue Laminated Timber of the NAFI Timber Manual