Posted August 4th, 2014 by Christy Serafini
Most people have had experiences with rainscreens even if they don’t realize it. A rainscreen is similar to a tent fly, the system used to keep the rain out and the tent dry during a camping outing. It does this because the tent fly frame separates it from the tent’s fabric.
A rainscreen on a building works in a similar fashion. The rainscreen cladding (or layer) keeps rain and moisture away from the building, ultimately protecting it from the elements of weather that can lead to rot, rust, and other ruin. The rainscreen system maintains a space between the cladding and the building’s exterior wall; this prevents water from infiltrating a wall’s structure.
Vented Versus Ventilated
Most rainscreens come in two types: ventilated and vented. A ventilated rainscreen cladding has a continuous air space, with openings at the top and the bottom. This encourages airflow (which accelerates drying) when water gets near the building’s exterior. But, air space is only part of the system: in order to assure that extraneous water and bugs don’t get near the building, the open cavity must be protected with overhangs as well as a moisture barrier over the sheathing. This barrier creates a drainage plan on the outside of the exterior wall. Some ventilated systems also have insulation that is rigid and water resistant; this improves energy performance and reduces the chances of condensation building up.
Ventilated systems are common in small commercial buildings. Vented systems offer much of the same as ventilated systems, but the main difference is that vented rainscreen claddings are open only at the bottom. They encourage draining but – because they are closed at the top – they do not have enough airflow to greatly speed up the drying process.
There are many benefits to installing a rainscreen system on a commercial building. One of the biggest benefits is that the barrier’s weather resistant elements keep moisture away from the building’s wall. Another benefit is the innate mold control properties: a rain system allows for water vapor to evaporate behind the buildings insulation. This reduces a dewy environment in which mold tends to thrive.
Some other benefits of a rainscreen are the promotion of water drainage and quicker drying times of the building’s brick, wood, or cement finish. Rainscreens are also aesthetically pleasing, with several lightweight cladding options and lots of design flexibility.
Finally, rainscreens reduce energy costs, something that is very important to the average commercial building owner. They do this by minimizing hot and cold air and thermal movement; in other words, in buildings with a rainscreen, cool air (in summer months) and warm air (in winter months) doesn’t escape as easily. This decreases the work load of the air conditioning unit and furnace (ultimately decreasing the utility bills).
Where Rainscreens Should be Installed
Rain screen systems protect both the health of a building’s occupants (such as those who work in an office) as well as the building’s longevity. For this reason, it is recommended that they be installed in any area where it rains, particularly in areas that have wet seasons. The only locations where rainscreens aren’t recommended are those with arid climates.