July 2015

How Do You Avoid The Effects Of Humidity?

Tina Cannedy and Amy Hockett

Stepping outside on a hot day can form condensation on your glasses and make your entire body sticky in a matter of minutes. If humidity can do that to us outside, what can it do to your construction project? Humidity can compromise the health of those living or working in a building while also damaging interior finishes and impacting energy demands.

Because we’re all thinking about cooling off these days, let’s look at a space that is regularly subjected to high humidity: an interior swimming pool room. A room like this requires tougher building products to battle elements like ongoing moisture. Mechanical ventilation, vapor barriers, dew points and perm ratings all play a part in controlling the humidity.

“While detailing a building where extreme conditions, such as high humidity, exist, architects have to balance many different design considerations,” states Amy Hockett, architectural specialist of National Gypsum. “The building envelope must impede moisture and air movement into the building, yet allow moisture to escape. National Gypsum has top-rated products that are ideal for every step of high-humidity construction.”

Certain building products are designed to withstand prolonged exposure to moisture and meet the special needs of these types of spaces, including the National Gypsum PermaBase® brand Cement Board, eXP® Tile Backer and DEXcell® brand Cement Roof Board.

  • Made of Portland cement, aggregate and glass mesh, PermaBase Cement Board is versatile and ideally suited as an underlayment for a variety of applications, including floors, walls, countertops or ceilings, and is approved for saunas and steam rooms.
  • eXP Tile Backer is code compliant as a substrate for tile and other finishes in both wet and non-wet areas, high-humidity areas and fire-rated assemblies. Where long-term exposure to mold is a concern, the eXP® Interior Extreme, eXP® Interior Extreme AR and eXP® Interior Extreme IR Gypsum Panels are other excellent choices. These panels will perform under the most exacting conditions when coupled with architecturally specified interior and exterior finish systems, such as Sto, Dryvit and Parex USA.
  • DEXcell Cement Roof Board products offer superior defense against moisture and carry a number of approvals to meet various industry standards.

“While developing designs, you must consider the effect interior humidity will have on a wall assembly to prevent condensation inside the cavity,” says Tina Cannedy, construction design manager of National Gypsum. “For interior pool room specifications, National Gypsum partners with coating manufacturers that can run dew point and/or WUFI analysis to determine if the specifications work for the intended use. This type of analysis provides designers like me with the information I need to select the correct materials for the project.”

Integrating National Gypsum products into rooms subjected to high humidity will give you peace of mind, so you can build indoor swimming pools, spas and whirlpools with confidence. We stand behind the consistent quality of our products and the extended life they offer.

For details about designing a sustainable space that can help beat the elements like humidity, contact your construction design manager today. We are here to help you design better.

Product Overview

Consider specifying DEXcell® brand Cement Roof Board in one of your upcoming projects!

Made of Portland cement, lightweight aggregate and glass mesh, DEXcell is great for all commercial roofing applications. This lightweight moisture- and mold-resistant cement board provides an exceptionally hard, durable surface. It also offers excellent freeze/thaw protection and fire resistance. Ask us about it today.

Project Profile

Harris Teeter Grocery Store

Harris Teeter Grocery Store, Charlottesville, Virginia
Ruddick Corporation
Ron Kirkpatrick
The first supermarket to receive LEED certification

In 2009, Harris Teeter grocery store built the first supermarket to receive LEED certification by incorporating special energy and environmental design components. During construction, more than 30 percent of all building materials were manufactured regionally (within 500 miles of the store), 82 percent of all construction waste was recycled, and 50 percent of all the wood came from certified sustainable forests.

Read More About The Project

Continuing Education

As temperatures continue to rise, find respite inside and develop your professional skills through our continuing education courses. This month, we recommend:

Cement Board and Exterior Finishing Systems
1 hour/1 AIA/CES
Learning Unit
Advantages of Using Cover Boards in Low-Slope Roofing Assemblies
1 hour/1 AIA/CES
Learning Unit

Animated Videos

PermaBase® Masonry Veneer Installation

Watch how easy it is to install PermaBase® brand Cement Board in a commercial masonry veneer wall installation.

Watch Now


Warren Barber
Technical Marketing Manager

Scott Hughes

Eric Marsal

Thad Goodman

Tina Cannedy

Pat Grotlisch

Amy Hockett
Architectural Specialist