Moisture Management


Dry means durable. Moisture Management

Controlling moisture, vapor and air flow is critical to the integrity of the building.

CertainTeed Building Science resources help you learn about moisture-flow mechanisms and the emerging science for overcoming mold, decay and weather related damage.

Managing moisture in a building is important because dry building envelopes perform better thermally which makes buildings more energy efficient. Dry building envelopes are also more durable, comfortable, healthful, and require less maintenance and upkeep.

Building science recognizes the influence of temperature, precipitation and humidity on building envelope performance, as well as material selection and placement in the assembly. Many residential and commercial building codes have changed in recent years to better reflect moisture control practices in building envelope design. Climate now plays a much larger part in prescriptive code requirements that include:

  • Interior vapor retarder use and placement
  • Building air leakage control and air barrier specifications\
  • Water resistive barrier and window flashing requirements
  • Ventilation and drainage space requirements behind claddings
  • Roof and foundation system ventilation requirements

Some of the changes improve the building envelopes ability to dry to the inside or outside by removing requirements for traditional interior vapor retarders in moderate climates, as well as increasing the need for a drainage and ventilation space behind exterior claddings. Minimum requirements for building air tightness as well as the integration of water resistive barriers and window flashings into building envelope system design reduces the amount of wetting that occurs in the first place. Changes also recognize that complex systems that have been traditionally ventilated, like attics and crawl spaces, can be designed as closed systems when the appropriate materials and components are combined to effectively manage moisture.

Today building scientists are able to predict the impact moisture will have on a building envelope over time using transient heat and moisture transfer – commonly referred to as hygrothermal analysis. Specialized software helps the user visualize such factors as: surface condensation and mold growth potential; the wetting and drying potential of the building envelope; and moisture content of building components. This analysis helps building designers evaluate potential pre-construction moisture risks and also helps analyze and solve moisture problems post-construction.

CertainTeed’s Moisture Management library contains videos, articles, white papers, educational presentations and literature on the challenges and threats of moisture penetrating the building as well as the advanced state of materials and scientific understanding of how to control its damaging potential.
Included are:

  • Illustrations of four moisture flow mechanisms
  • Descriptions of the various US climate zone designations
  • Vapor retarder performance metrics and applications
  • Design considerations necessary to manage moisture in wall assemblies
  • The concept of hygrothermal analysis
  • Roofing system design considerations for moisture management
  • Fenestration product installation considerations
  • Key moisture sources in building

From learning about diffusion to understanding how air affects the flow of moisture in a building, CertainTeed Building Science
is the professional resource to count on when moisture is in motion.