The Acrylic Stucco EIFS Challenge
Over the last number of years stucco finishes, both cementitious and acrylic, are under scrutiny and have been the topic of many technical and non-technical discussions. The thickness of cementitious stucco has been an issue in Alberta over the last 5-10 years and acrylic stucco has been the main topic of discussion among designers, building owners and building officials.
Korax Solves The EIFS Problem
The problem with “leaky condos” in British Columbia has been the topic of many newscasts and it has affected many individuals. Many papers have been written on the topic most of them by the proponents of the system (especially the acrylic stucco), which provided little or no explanation as to why so many buildings experience so many problems. The problems experienced by these systems are blamed on applicators, contractors, designers, etc.
This site deals with the issues and factors affecting the performance of these systems and introduces the principles of a vented rain screen to stucco finishes. The principles of rain screen wall assemblies have been known to designers and building officials for many years and because of the problems encountered with other wall assemblies it is now the preferred system, and one recommended by designers and building officials.
Including details for Wood Stud, Metal Stud, Concrete Block Walls and Foundations.
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Acrylic Stucco EIFS Legal Issues Continue
Although there have been huge advances in the composition and application of EIFS finishes, lawsuits and apposing arguments have flourished. Water penetration has lead to moisture issues, mold growth and structural rotting.
Here are some links to other information and discussions regarding the use of standard EIFS Systems.
The content of these articles and opinions are of the individual authors.
When you have reviewed the issues you will see why -
Have you experienced problems with mold in your walls or have questions
concerning building envelope design, you can contact Dr. Mike Hatzinikolas, Ph.D., P.Eng., F.C.S.C.E at:
Tel: 780.455.5116 or firstname.lastname@example.org
What do the Government agencies say about EIFS systems?
The NRC (National Research Council)
Document T2/8 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 EFIS 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 Wall System!
The National Building Code of Canada 2005 Volume 1 - Division B, 184.108.40.206
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, or
The National Building Code of Canada 2005 Volume 2 - Division B, A-220.127.116.11.(3) 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.
The Korax RainScreen Panel™ satisfies these basic principles of a vented rainscreen as per the National Building Code.
Stucco RainScreen Panel™ System is a trademark of Korax Technologies Inc.
Stucco RainScreen Panel™ System Canadian patent pending #2249509 l US patent# 6298620