Specification for Successful Projects

Key Point: A specification requiring continuity of control layers, communication between trades, verification of material compatibility, and quality control is critical to success.

There are a few key items that designers can include in their specifications to help ensure the control layers will be installed properly and that the interface details are not missed. The specification sets up communication between all parties throughout a project and puts potential problems under a continual, multidisciplinary spotlight that helps a team to catch them as early as possible, even during the design stage. Items such as defining the complete scope of work for the contractors installing the different control layer assemblies and specifying the party responsible for installing flashing and transitions between systems assigns responsibility and allows for easier scheduling and quality assurance in the field.

First, require shop drawing submittals that include details at the many interfaces around the building enclosure. This will confirm everyone understands how the materials are to be installed and who will install them. This will also highlight areas that may have been missed in specifications as to which trade is responsible for which part of a specific detail. Critical detail locations are often difficult to illustrate on two-dimensional drawings. They can require exploded diagrams and sequenced information to better communicate the design intent.

Next, the materials selected for each part of the system need to be vetted. Questions such as will the materials adhere to each other, are they chemically compatible, and can they be installed in the order required, should be answered before construction starts. This information should be easily available from the manufacturers chosen, along with support to assist in any detailing questions. If substitutions are made, compatibility and adhesion of the components needs to be reconfirmed.

Additionally, architects can specify mockups in the project documents and even require performance testing of the mock-up to confirm interfaces are functioning as intended. This helps to flush out the constructability of the design and anticipate issues that may arise during construction. Mock-ups can also help installation crews by being a reference as to agreed upon methods and providing a reference for any new crew members on the project. Having a physical example allows for confidence that, when the roof and other assemblies are installed, the team can feel assured that it will perform the way it was designed to.

Finally, quality control and operational maintenance are ways to ensure long-term performance of the building enclosure. It is important to have quality assurance and quality control occur throughout the project and not be confined to a final walk-through in the field. Fixing issues or missed details at the “almost done” stage is very hard when faced with sequencing realities.

There are four critical components to a robust detail: the material, its installation, simplification of the detail where possible, and thorough communication among design and installation professionals. Four quick checks can help design professionals ensure these are met.

They are:

1. Material: are the selected materials compatible, will they adhere?
2. Installation: how are the control layers installed and interfaced, what is the order of operations?
3. Simplify: can fewer materials be used, or installation done in fewer steps to avoid confusion in the field?
4. Communication: is the whole team engaged in conversation to create a multidisciplinary approach?

Architects strive to achieve a building that strikes a delicate balance between aesthetics and performance. From the architect's perspective, one of the biggest challenges is meeting this design vision without jeopardizing performance. This is highlighted most at the roof-to-wall interface. Blending high-performance with aesthetics means making the functional elements, like control layers, essentially invisible to the naked eye but still have them perform as designed. With any project, there are a number of factors to consider when choosing the right design: overall performance, sustainability profile, potential risks, and more. Understanding building science and creating robust control layer details and specifications helps professionals deliver better solutions for their customers.

End Notes

¹Lstiburek, Joseph. “BSI-001: The Perfect Wall." Building Science.com Corporation. July 15, 2010. Accessed June 7, 2023.
²Ibid.

Andrea Wagner Watts is the Building Science Education Manager for GAF, engaging with industry professionals to provide guidance, technical support and education for roof and wall assemblies. With more than 15 years of experience in the industry, Andrea strives to improve the overall performance of the building enclosures through application innovation, product development and building science research. Andrea has published on building science, assembly interfaces, durability and resilience and holds multiple patents. She serves as an executive board member of ABAA, is the co-chair of their Technical Committee and chairs the ASTM E06 Task Group on air barriers.