This is the fifth post in a series by J. David Odom (ASHRAE), Richard Scott (AIA/NCARB/LEED AP), and George H. DuBose (CGC). It was first published as a mini-monograph for NCARB (National Council of Architectural Registration Boards).

LEED Credit Number

Description

Issue

Comments

Sustainable Sites (SS)
Credit 7.2
Heat Island Effect: Roof Option of installing a vegetated roof
for at least 50 percent of roof area.
Vegetated roofs have more moisture
due to irrigation and constant hydrostatic
head of water than typical roofs,
making it difficult to prevent water intrusion
and condensation problems. Moisture migration & concentration between impermeable membranes
is a possibility.
Energy & Atmosphere (EA) Prerequisite 1 and EA Credit 3  Fundamental Commissioning of the Building Energy Systems and Enhanced Commissioning Enhanced commissioning addresses only the most forgiving climates. 1. The typical commissioning design review is not likely to predict the potential for future moisture and mold problems.
2. The reviews normally do not incorporate an analysis of the building envelope performance.
 EA Prerequisite 2 and EA Credit 1 Minimum Energy Performance Required and Optimize Energy Performance Increases in energy performance can reduce moisture control in buildings. 1. Increased thermal insulation changes wall system performance (dew point location) with possible condensation in wrong location.
2. Modifying heating, ventilating, and air-conditioning (HVAC) control schemes alters equipment run times and impacts moisture control.
 EA Credit 5: Measurement & Verification  Ongoing energy measurement and verification Sacrificing adequate relative humidity control to reduce energy usage. Any good energy management plan must be subservient to adequate moisture control.
Materials and Resources (MR) Credits 1.1 and 1.2 Building Reuse: Maintain 75 percent to 95 percent of Existing Walls, Floors, & Roof Moisture control performance of existing building envelope components re-used under this credit. 1. Quality and performance of existing components such as flashing, rainwater barriers, air barriers, need to be investigated and possibly tested.
2. Model both new and re-used component to identify how each component will act towards good moisture control – this includes interaction with the HVAC system.
 MR Credits 1.3, 2.1, 2.2, 3.1, and 3.2 Building/Materials Reuse and Construction Waste Management Inadvertent reuse of previously water damaged and/or mold contaminated materials presents an increased risk. Construction workers at risk of handling mold-contaminated materials. 1. Mold contamination is not often visible in the occupied side of materials and is not generally found by air testing in a construction environment. Destructive testing and evaluation may be required.
2. Construction waste management plan may need to include section on handling moldy materials.
 MR Credit 6 Rapidly Renewable Materials Use of rapidly renewable natural building materials and products without understanding their properties related to water (permeance, absorption, etc.). The mixture of synthetic materials with natural materials in the building envelope can create increased potential for moisture condensation and entrapment.
 Indoor Environmental Quality (EQ) Prerequisite 1, EQ Credit 1, and EQ Credit 2 Minimum Indoor Air Quality (IAQ) Performance, Outdoor Air Delivery Monitoring, and Increased Ventilation Ventilation in many parts of the United States must be carefully designed to avoid moisture problems. Increased ventilation air should never be added without an overriding control of both pressurization and dehumidification.
EQ Credit 3.1 Construction IAQ Management Plan: During Construction Typical construction sequencing does not always allow for meeting credit objectives for protection of materials from water damage. Construction sequencing needs to be reviewed and material protection measures understood and enforced.
 EQ Credit 3.2 (and 3.1) Construction IAQ Management Plan: Before Occupancy Pre-occupancy flush out. Introducing required air for this credit in many geographic areas can result in indoor moisture problems.
 EQ Credit 5 Indoor Chemical & Pollutant Source Control Requires significant exhaust rates for source control. Local exhaust can result in local depressurization and introduction of humid outside air into building envelope. It can also result in inadvertent pollutant movement within a building.
 EQ Credit 6.2 Controllability of Systems: Thermal Comfort Providing operable windows can allow untreated humid air or rainwater to enter building. If operable windows are installed, consider sensors and automatic overrides.
 Innovation in Design (ID) Credits 1.1-1.4 Innovation in Design Recognizing the inherent increased risk of using new products that have less in-field experience. 1. Probably unrealistic for the design and construction team to understand the performance characteristics and limitation of new products and the additional risks that their use might carry.
2. Particular concern about the introduction of new products into the highest moisture risk areas of the building (i.e., the envelope and the HVAC system) since in these areas there is added risk.

To be continued…

J. David Odom is a Vice President and Senior Building Forensics Consultant with Liberty Building Forensics Group. He has managed some of the largest and most complex mold and moisture problems in the country, including the $60M construction defect claim at the Hilton Hawaiian Village in Honolulu and the $20M claim at the Martin County courthouse. He has also managed over 500 projects for the Walt Disney Corporation dating back to 1982 that have included technical issues related to corrosion, moisture, and design & construction defect-related problems. He has published numerous manuals and technical articles, including a monograph on moisture and mold for the National Council of Architectural Registration Boards (NCARB). For more information, contact J. David Odom at d.odom@libertybuilding.com.

With over 35 years of experience, Richard S. Scott is an expert in the areas of architecture, interior design, and building forensics, with a focus on moisture-related building problems. He is certified by both the American Institute of Architects/AIA Florida and the National Council of Architectural Registration Boards (NCARB). He has published over 30 articles, and has lectured or presented at nearly 40 seminars or events. Mr. Scott has developed various training courses, including a 16-hour IAQ training course for NASA and an 8-hour water intrusion prevention training course for the Naval Facilities Engineering Command (NAVFAC). He can be reached at r.scott@libertybuilding.com.

George H. DuBose, CGC is a certified Florida General Contractor and Vice President with Liberty Building Forensics Group, a firm specializing in moisture intrusion, mold problems, litigation support/buildings forensics, problem-avoidance peer reviews, commissioning, and implementation of green buildings. He has authored numerous articles and co-authored three manuals on moisture-related indoor air quality (IAQ) problems and building commissioning. He has diagnosed and solved hundreds of moisture and mold related building problems worldwide. DuBose can be contacted at g.dubose@libertybuilding.com.