The moisture layer in an enclosure assembly controls the passage of water even after extended exposure to any moisture. The water control layer is the continuous layer (comprised of one of several materials and formed into planes to form a three dimensional boundary) that is designed, installed, or acts to form the wall’s rainwater boundary. In face-sealed, perfect barrier systems, this is the outer-most face of the enclosure. In concealed barrier perfect systems, it is a plane concealed behind the exterior face. In drained systems, the water control layer is the drainage plane behind the drainage gap or drainage layer. In storage reservoir systems, the rain penetration control is typically part of the innermost storage mass layer.
Key components for moisture control in wall systems are: sheathing joint treatments, rough opening protection, transition membranes and an effective air/moisture barrier. Pre-formed drainage mats can also help remove water, as well as promote drainage and drying in vertical wall assemblies beneath stucco, stone, siding and thin brick veneers. (Example Sto DrainScreen)
Fluid-applied, waterproof air barrier membranes in wall construction have proven their worth as excellent protection against moisture intrusion and air leakage, delivering thermal value in the form of significant energy savings in hot and cold climates. (Example: StoTherm® ci XPS) These fluid-applied air/moisture and vapor barriers may be used with all types of above-grade claddings and wall substrates. Trowel-applied air/moisture barrier and adhesives may be used for above- and below-grade walls and for attaching continuous insulation.
Look for wall systems that provide seamless air and moisture control as opposed to building- wrap barriers that are typically penetrated by staples and fasteners for attachment. An entire wall assembly that provides seamless protection will provide reliable control layers for air and moisture intrusion.
Wall coatings can also offer protection against moisture and rain, along with UV degradation, heat, salt, wind and humidity. Coatings with permeance can help resist blisters and mold in a wall cavity, which can be caused by moisture resulting from vapor migration.
In addition to repelling external water and moisture, an advanced coating system can also help resist cracking and prevent corrosion in substrates containing steel. While every building is different and coatings will vary based on cladding types and other variables (such as regional climate), wall coating formulations today are not only weatherproof, but can offer vapor permeability, crack-bridging capability, and mold resistance; some are so high-tech they create a durable surface that both beads water and sheds dirt, thus self-cleaning a wall. (Example: StoColor® Lotusan®)