Rear-Ventilated Rainscreen (RVRS) and Cladding Types
Jeff Ker, Engineered Assemblies
Facades systems have always been one of the most important parts of sustainability. We are only now coming around to realize just how important. Facades, if done properly, will be a rear ventilated rainscreen. They will be part of an outboard insulated envelope and will be high performance. In keeping with that methodology, they will then be the Primary Passive Environmental Control System.
Facades have always been on the front lines so to speak. They are often the single largest building component charged with insulation in addition to being most vulnerable to the substantial dictator – the environment.
Managing the abuse the environment delivers is a holistic endeavour and is only possible with a combination of materials, good design and proper assembly. If we had to pick one ingredient to start with, ventilation is the first. Whether you have a marginally absorbent façade material or not, ventilation is always good – never bad. It helps the entire assembly maintain a handle on moisture.
Having an active plenum, as outlined in the drawing detail, ensures the circulation of air is constant in good times and bad. The plenum can only function best when unobstructed and with the combination of adequate intake and exhaust vents.
Having adequate ventilation/air flow means the substructure supporting the façade material can see a longer lifespan and the insulation can function at its maximum potential in its dry state.
Placing a secondary drainage plane in front of the insulation (behind the plenum) will further thwart the intrusion of precipitation, minimize wind washing, and provide a visually pleasing veil to hide substructure and insulation through open joints of facade panels.
When all the components are chosen and assembled in the spirit of achieving their greatest lifespan, we can avoid premature demolition and concentrate on maximizing thermal performance and moisture management. This, in itself, is a pathway to sustainability.