Protecting the building envelope in commercial construction

Feb 5, 2024

Optimizing building performance relies heavily on the design and products used to enclose the structure


For commercial construction, a structure’s overall resiliency and energy efficiency are directly impacted by the quality of the building envelope. As the barrier that separates the building interior from the external environment, the building envelope represents the frontline of defense against the elements.

Protecting a building's enclosure requires a wide variety of high-performance building materials. For external wall systems and roofing, National Gypsum Company provides select high-value products manufactured by its affiliate companies Gold Bond Building Products, LLC and PermaBASE Building Products, LLC.

Understanding the components of a building envelope

According to the U.S. Environmental Protection Agency, the average commercial building wastes nearly one-third of the energy it consumes. From inadequate insulation to poorly sealed exterior wall openings, such as windows and doors, an inefficient building envelope can have a significant impact on operation costs, occupant comfort and the lifespan of the structure.

The “Perfect Wall”

Improving a structure’s R-value and creating an effective building envelope requires understanding the building science of an exterior wall and roof system. Often called the “perfect wall,” this building envelope design minimizes heat transfer, maximizes energy efficiency and provides optimal comfort for occupants.

A perfect wall system consists of the following components, with particular attention paid to the order in which they are assembled:

  • Sheathing
  • Vapor barrier
  • Thermal insulation
  • Weather-resistant and air-barrier
  • Exterior cladding

“In the perfect wall, the control layers that protect the building from all outside elements — rain and runoff, air movement, heat flow and water vapor — are placed on the exterior side of the wall sheathing,” said Matt Gallagher, gypsum product manager for Gold Bond Building Products, LLC. “The addition of a continuous exterior insulation creates a building envelope that can play a significant role in ensuring the structure's longevity, energy efficiency and overall performance.”

The elements and principles that apply to a perfect wall also apply to the roof.

The “Perfect Roof”

A perfect roof design places the weather-resistant control layer above the insulation and underneath the waterproofing membrane to protect the structure and ensure continuity of the building envelope.


Potential problems associated with an ineffective building envelope

When a building enclosure sacrifices any of the components of the perfect wall outlined above, higher energy costs are just one of the potential issues that can arise. Others include:

  • Temperature Variations: Inconsistent indoor temperatures due to heat gain or loss can create discomfort for occupants, including cold drafts in winter and hot spots in summer.
  • Mold and Mildew Growth: Inadequate moisture control can lead to condensation problems. Condensation can cause mold growth, wood rot and corrosion of metal components.
  • Structural Damage: Moisture infiltration, especially in the form of water leaks, can damage structural elements, such as framing and sheathing. Over time, this can compromise the building's integrity.

"The accumulation of damage from moisture, temperature fluctuations and energy inefficiency can significantly reduce the lifespan of a building and increase maintenance and repair costs."

Matt Gallagher


Matt Gallagher

Gypsum Systems Product ManagerGold Bond Building Products, LLC

A trusted partner in building envelope protection

As modern construction and code compliance continue to demand more sophisticated and effective building envelopes, specifying and installing the right materials can help ensure your project meets these requirements. And that starts with the base layer for exterior wall and roof assemblies.

With a breadth of products provided by National Gypsum, we’ve got you covered from the roof to the slab.

eXP Sheathing: A stable base for building envelope protection

The exterior walls and soffits of the building envelope are critical elements that deserve attention. Most of these assemblies require sheathing to be attached to the outside of the framing as a water-resistant underlayment for various materials. Depending upon where your project is being erected, these assemblies could be exposed to wind, rain, snow and extreme temperatures for extended periods during the construction process and afterward.

With eXP Sheathing’s Sealed Surface Technology, your project can withstand the elements. For both wood and metal construction, eXP Sheathing provides a solid substrate for various air and water-resistive barriers and is a component in Exterior Insulation and Finish Systems (EIFS).

eXP Sheathing offers a moisture- and mold-resistant panel with superior extended-exposure capabilities. It is lightweight, handles easily and is used for a variety of finishes.

Other benefits include:

  • Fire-resistant material helps protect framing elements, even when cladding is combustible
  • Meets ASTM C1177, Standard Specification for Glass Mat Gypsum Substrate for Use as Sheathing
  • Provides superior water resistance without impeding vapor transmission
  • Resists the growth of mold per ASTM D3273 with a score of 10, the best possible score
  • Offers a 12-month extended exposure warranty for typical weather conditions
  • Dimensionally stable under changes in temperature and relative humidity

PermaBASE CI: A durable substrate and high-density insulation, all in one

To improve a structure's R-value, many construction designs now incorporate a layer of continuous insulation to provide a stronger thermal barrier. PermaBASE CI Insulated Cement Board combines the strength and benefits of a composite cement board with rigid insulation to create an ideal substrate for exterior finishes that meet or exceed most continuous insulation requirements. Combining the insulation and cement board into a single panel also saves installation time and labor.


PermaBASE CI is made of Portland cement, aggregate and glass mesh, providing an exceptionally hard, durable surface that will not rot, disintegrate or swell when exposed to moisture.

Other benefits include:

  • Laminated with a R-4, R-6, R-10 and R-16 Insulation
  • Meets or exceeds energy code requirements
  • NFPA 285 approved for adhered veneer finishes such as manufactured and natural stone, thin brick and tile, as well as direct applied coatings of synthetic stucco.
  • UL GREENGUARD Gold Certification for low chemical emission and improved indoor air quality

DEXcell Roof Boards: A reliable component in dynamic roofing systems

While the exterior walls represent the largest component of a building envelope, a structure’s roof must also be given the same level of consideration. As a result, the roof is a critical component of a building envelope, playing a significant role in ensuring the overall functionality, durability and energy efficiency of a structure.

To serve its primary purpose — protecting the building and its occupants from external weather elements — a well-designed roof prevents water infiltration and moisture-related damage.

DEXcell Roof Boards can be used as a roofing substrate or coverboard, adding thermal protection and support for the roof membrane. They also provide increased fire safety and acoustical enhancement.

Other benefits include:

  • Protects insulation from foot and equipment traffic
  • Improves fire ratings
  • Protects against storm and hail damage
  • Increases wind uplift ratings

Safeguarding the building envelope is a fundamental aspect of constructing a durable and resilient commercial structure. Leveraging these innovative products, not only enhances the safety and longevity of the buildings but also contributes to a sustainable and secure built environment for generations to come.

As a trusted provider of high-performance building materials, National Gypsum has the expertise and technical support to help you protect the building envelope on your next project. Contact 1-800-NATIONAL® Construction Services for insights into fortifying the building envelope.