PRESWITT NON-COMBUSTIBLE RAINSCREEN
EXTERIOR INSULATION & FINISH SYSTEM


General Description

The Preswitt System utilizes the standard Non-Combustible System with modifications over a primary lamina which has been trowelled over an approved substrate. The primary lamina acts as an air barrier and as a secondary barrier against water ingress into the building. Preswitt's M.P. Flexcoat mixed 50/50 by weight with Portland cement is the preferred trowelled on membrane, however if its high resistance to water vapour transmission conflicts with the building envelope design, Preswitt's regular basecoat may be substituted. Reinforcing mesh is required in both of these membranes. Peel and stick strips are applied at expansion joints, window flanges and as required to create a complete sealed air tight and weather resistant envelope. Careful inspection of the envelope for leaks and necessary repairs is essential before proceeding with the installation of the EIFS.

In order for the system to provide drainage for incidental water intrusion and air pressure equalization the following modifications to the mineral wool insulation and its installation were introduced.

  1. The mineral wool panels are installed vertically and each panel has a vertical groove cut in the back section to assist air ventilation and provide a channel for egress of incidental water that might find its way into the system. A 3/8" notched trowel is used to apply the adhesive compound to the wall surface in a vertical manner.

  2. At the bottom of each wall section the system is supported by a corrosion resistant angle which is perforated to allow the introduction of air for pressure equalization and allow incidental moisture that may have entered the system to escape.

After installation of the insulation the application of the reinforced N.C. Basecoat and Quality Finish is the same as for the standard Non-Combustible EIF System.