Preventing water infiltration requires knowledge of material properties, compatibility, and installation techniques. Establishing and verifying such techniques is a key step in achieving the intended product performance.

Dörken Systems Inc., formerly Cosella-Dörken, specializes in developing high-performance air and moisture barriers. RDH assisted Dörken in determining best practices for rough opening preparation and installation of windows using their DELTA® product line, taking a multi-pronged approach that included material and assembly testing along with the development of common details to support the creation of practical instructional resources.

Results from laboratory and field exposure testing confirmed material compatibility within the product line and informed the development of several alternate rough opening preparation details. Alternate configurations included flanged and non-flanged windows, pre-strip versus cut-out installation, and four sill conditions (a flat sill, a sloped sill, a backdam, and a design using DELTA® corner-reinforcing products). A mock-up of each detail was assembled and documented. Once the windows were installed, air and watertightness testing was conducted at RDH’s window testing facility.

Upon successful completion of the tests, the team at RDH created 3-D models of the details to illustrate the step-by-step installation process. Finally, we provided hands-on training to Dörken technical and sales staff to ensure they were prepared to discuss the best practice techniques that were determined.

The end result of RDH’s approach included not only testing results, but multiple how-to videos, two builder installation guides, and hands-on training to ensure that product information was translated into practical guidance.





September 27, 2021


Dörken Systems Inc.

Project Completed:


Key Services

Knowledge Sharing

Research at RDH Building Science Laboratories (RDH-BSL) is wide-ranging—from R&D projects that help manufacturers with product development to major research programs that help government and industry partners answer fundamental questions or address large-scale issues. Each project is approached as a unique challenge, requiring a tailored solution.

We undertake these projects in our two laboratory facilities and at field research sites in multiple climate zones across North America. Our staff includes highly trained and experienced researchers and technicians who understand the behaviour of assemblies, components, and materials, as well as the construction and design-related issues that impact performance.

In addition to laboratory and field research, computer-based modeling is an indispensable tool. We analyze and extend measured results using various modeling programs, including two- and three-dimensional heat flow programs (THERM, HEAT 3D), hygrothermal modeling software (WUFI Pro and WUFI Plus), and other in-house proprietary software. Many projects include several phases to allow validation of modeled results with measured data.

Graham Finch | Dipl.T., M.A.Sc., P.Eng.

Principal, Senior Building Science Specialist
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James Bourget | ABET, RRO®, CPHT

Principal, Construction Specialist
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Dave Ricketts | M.Sc., P.Eng., FEC

Founder, Senior Principal, Senior Building Science Specialist
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