Naturally breathable wall systems: TESS Thinset Exterior Surfacing System

Breathability matters: Moisture is the enemy.

Water vapor must be allowed to escape to maintain a dry, healthy wall system. If the weather barrier and base coat breathe, but the top or finish coat does not, the efficacy of the whole system breaks down. Weather barriers are breathable materials that allow air and water vapor to pass through them. Vapor permeable membranes used as part of a well-constructed wall system have perm rates above 58. Most acrylic finishes, however, have perm rates between 14 and 40, thereby enabling water vapor to be entrapped behind the finish. TESS Finish, with a high perm rate of 72, allows water vapor to quickly expire through the lamina of the wall system.

Breathability, in addition to drainage is crucial to the long term durability of the structure. Water vapor that is inhibited from moving between the inside and the outside of the structure can lead to a variety of undesirable conditions such as wood rot, mold growth, termite infestation, and condensation on interior walls. TESS Finish is the first product that applies like an acrylic stucco while retaining the superior performance properties of a naturally breathing cement stucco.

The truth about breathability: While some manufacturers of acrylic EIFS finishes claim that their products are breathable, the fact is that textured acrylic finishes function as vapor barriers much the same as smooth acrylic paints. By contrast, TESS components are all engineered for superior vapor-permeability so that air and water vapor pass freely through the lamina. In blind independent laboratory tests, TESS Finish proved to be 3.3 to 4.2 times more vapor-permeable than two leading brands of EIFS finish.

Water repellent: When tested for hydrophobicity, TESS Finish demonstrated an ability to repel water just like acrylic stucco while allowing water vapor to escape, ensuring a drier, healthier wall system.

TESS Thinset Exterior Surfacing System