There are several different methods to wall construction, whether it is load bearing masonry, a cavity wall, or a barrier wall. The overwhelming majority of walls constructed would be considered barrier walls. The barrier wall assembly would have the exterior veneer directly applied over the weather-resistant barrier. This type of wall construction includes wood siding, fiber-cement siding, manufactured stone veneer, stucco veneer, among others.
The problem with this type of construction is not directly correlated with problems by using one of the exterior veneers listed above. The problem arises from the wall assembly. Barrier walls are constructed to stop, or deflect weathering with the exterior plane of the veneer. This method is usually constructed as an imperfect barrier, and has no control of water penetration. This is due to voids in a siding application, or cracks in a stucco, or stone veneer application from settling, weather, etc. The wall does not stand a chance if the first line of defense has no control of the moisture entering into the assembly. Older homes that had an exterior veneer that got wet would have the opportunity for the saturated veneer to dry. This is due to the wall assembly allowing air flow from the interior to ventilate the veneer. This would mean higher energy bills to heat, and cool, but there generally would not be moisture issues with the exterior. The change in construction methods to incorporate sustainable design or to have an insulation method has changed the way the assembly ventilates. It would be the opposite. Energy bills are lower, due to the structure not allowing air leakage, but the wall is getting wet, with not the same opportunity to dry. Having a saturated wall with no opportunity to dry amplifies the potential for a moisture problem. Wall failures due to moisture problems are becoming more and more common.
There is a solution. By constructing a wall that incorporates a drainage, and ventilation mat, the barrier wall can be transformed into a Rainscreen, or cavity wall. This is best provided by Driwall Rainscreen. Driwall Rainscreen is a drainage, and ventilation mat that eliminates moisture, and moisture vapor within the wall assembly. This type of wall assembly assumes some moisture will penetrate the exterior veneer, and the penetrating moisture will be collected and discharged out of the wall. Along with that, due to the structures tightness, the greater need is for a ventilation method. The Driwall Rainscreen separates the exterior veneer from the weather-resistant barrier to provide airspace. This is crucial to increase airflow in the wall, which allows it to breathe, and stay dry. Types of veneers that can include Driwall Rainscreen in their assembly would be wood siding, fiber-cement siding, stone veneer, stucco veneer, thin veneers, and brick. By transforming a barrier wall into a Rainscreen, or cavity wall, you are assuring the end result is a high R-Value, with no concern over moisture within the wall.
