The National Research Council Document T2/8 from Sept 2000

states that -

"While drainage is the primary mechanism in this moisture management strategy, substantial amount of moisture will also be absorbed by the surfaces of the drainage mat and adjacent materials. This moisture needs to be dried through the EIFS lamina, making the performance of the system somewhat climate-dependent. This explains why industrial development was focused on systems in which reduction of moisture loads would eliminate the need for testing and/or durability assessment. Such a system could be achieved with rainscreen principles for a mechanically attached EIFS that includes a vented, wide air cavity. There is, however, no such system on the market, ..."

Now there is such a system - The Korax Rainscreen Panel™!


The National Building Code of Canada 2005, Volume 1 - Division B,

Minimum Protection from Precipitation Ingress

1) Except as provided in Sentence (2), a cladding assembly is deemed to have a capillary break between the cladding and the backing assembly, where

a) there is a drained and vented airspace not less than 10 mm deep behind the cladding, over the full height and width of the wall..

b) an open drainage material, not less than 10 mm thick and with a cross-sectional area that is not less than 80% open, is installed between the cladding and the backing, over the full height and width of the wall,

c) the cladding is loosely fastened to the backing and behind each cladding component there is a clear air space that is

i) continuous for the full width of the component

ii) not less than 10 mm deep at the bottom of the component,

iii) not less than 6 mm deep over not less than 90 mm for every 230 mm of exposed height of the component.

The Korax RainScreen Panel™ is the only panel complies with all these specifications!


The National Building Code of Canada 2005 Volume 2 - Division B, A-
Position of Insulation

For thermal insulation to be effective, it must not be short-circuited by convective airflow through or around the material. If low-density fibrous insulation is installed with an airspace on both sides of the insulation, the temperature differential between warm and cold sides will drive convective airflow around insulation. If foam plastic insulation is spot-adhered to a backing wall or adhered in a grid pattern to an air-permeable substrate , and is not sealed at the joints and around the perimeter, air spaces between the insulation and the substrate will interconnect with spaces behind the cladding. Any temperature or air pressure differential across the insulation will again lead to short circuiting of the insulation by airflow. Thermal insulation must therefore be installed in full and continuous contact with the air barrier or another continuous component with low air permeance.

(editors comment - this means that any venting or drainage must be exterior to the insulation layer - the cold side!)

Implementing the Korax RainScreen Panel™ will satisfy these basic principles of a vented rainscreen as per the National Building Code.