Insulated Rainscreens: The Need to Rethink Conventional Design

AIA CREDIT: Yes

SCHEDULE:

5:30 – 6:00 pm (Reception & Socializing) - We kindly request not to arrive no more than10 minutes prior to scheduled start time.

6:00 – 7:30 pm (Presentation) 

7:30 – 8:00 (Q & A) 

ABSTRACT:

This presentation evaluates trends in wall design that are intended to meet or exceed energy mandates for continuous insulation in ventilated rainscreens. Potential pitfalls in current practices will be demonstrated with advanced simulations of rainscreen airflows and convective heat loss. Prevailing assumptions regarding moisture performance will be challenged with particular emphasis on the combined effects of thermal bridging and wind‐washing. Strategies for risk avoidance will be discussed in context with material selection, design, and construction quality control.

LEARNING OBJECTIVES:

1. Attendees will be introduced to emerging risks associated with the use of continuous insulation in ventilated rainscreens. Discussion will focus on the paradox of maximizing moisture transport while minimizing the adverse effects of convective heat loss. This presentation will address common insulation materials, varied rainscreen geometries, and expected imperfections in wall construction.
2. Attendees will be presented with a fresh perspective on how air moves through modern rainscreen systems. Graphic simulation results will demonstrate previously unseen flow characteristics as air encounters inlets, cladding attachment systems, and insulation gaps. Attendees will visually explore pathways for air and heat flow through air‐permeable insulation.
3. Attendees will gain greater awareness of the magnitude and effects of wind‐washing. Convective heat loss will be explored as a function of wind speed, insulation permeability, and localized velocity fields near cladding attachment systems. Attendees will also be introduced to novel approaches for assessing moisture risks resulting from the coupled effects of thermal bridging and convective heat loss in complex three‐dimensional assemblies.
4. Attendees will learn how to avoid these hidden risks to meet the difficult demands of today’s building enclosures. Furthermore, attendees will be challenged to achieve simpler, thoughtful designs for improved performance under expected and extreme conditions.

PRESENTER BIO:

M. Steven Doggett, Ph.D. | LEED AP, Principal Scientist | Built Environments, Inc.

Dr. Doggett is the principal scientist and founder of Built Environments, Inc., an architectural & building science consulting firm specializing in building enclosure design. His background includes extensive field experience in analyzing complex building enclosure failures, particularly those involving air, heat, and moisture transport. He combines this experience set with innovative design practices to assist multi-stakeholders achieve more resilient, higher-performing buildings. Dr. Doggett is actively engaged in enclosure design, assembly and material research, and performance simulations such as computational fluid dynamics, 3-D thermal modeling, and hygrothermal modeling. He has served as the principal scientist on hundreds of projects involving all markets and all building types. He also serves as a technical consultant for intellectual property development and manufacturing R&D. Dr. Doggett currently chairs the Minnesota chapter of the Building Enclosure Council, a multidisciplinary educational initiative by the National Institute of Building Sciences.

RSVP:

For BEC Chicago members, an RSVP invite will be sent out approximately 7 to 10 days in advance of event. For non-BEC Chicago members interested in attending, you may contact Jeff Diqui at jdiqui@imiweb.org to request an invite. The inviation will include a link to an RSVP.