Building Science

Best Practices for Continuous Insulation in Exterior Walls

Continuous insulation (CI) in exterior walls is an essential and required design component of energy efficient and high performing buildings. In fact, the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE 90.1) and the International Energy Conservation Code (2015 IECC) require continuous insulation in both commercial and residential applications.The ASHRAE Standard 90.1-2013 defines continuous insulation as insulation that is uncompressed and continuous across all structural members without thermal bridges other than fasteners and service openings. It is installed on the interior, exterior, or any non see through surface of a building’s envelope. The rise in the use of CI has occurred because of both economic and environmental reasons. Buildings designed with CI save money because CI stops thermal bridging; therefore, less energy is required for heating and cooling a building. Utilizing CI also reduces costs associated with mechanical ventilation, heating, and cooling. The use of CI is good for the environment because less energy consumption means fewer emissions of greenhouse gases, a known cause of global climate change. Continuous insulation is standard practice across all climatic regions of the United States and saves both energy and money. Best practices for continuous insulation in exterior walls consider thermal performance, fire, and moisture resistance in the design and construction.

R-Value Requirements in Eight Climate Zones - Continuous Insulation

Best practices for CI in the exterior walls follow the ASHRAE 90.1 and 2015 IECC codes and standards. The standards specify the amount of insulation required, based on the buildings climate zone, to eliminate thermal bridging and increase the effective R-value in a wall assembly. Builders, architects, and designers utilize CI to create energy efficient, airtight structures that save both money and reduce greenhouse emissions.

Fire Resistance - Continuous Insulation

Unfortunately, the majority of continuous insulation solutions are combustible materials. This makes the CI requirements more difficult to meet because the International Building Code (IBC) requires making walls of noncombustible components and evaluating the walls by industry standards of fire resistance. Two industry standards gauge the fire resistance of wall assemblies: the ASTM E119, Fire Tests of Building Construction and Materials and the ASTM E2257 Standard Test Method for Room Fire Test of Wall and Ceiling Materials and Assemblies.

  • ASTM E119 (and-and ULC-S101) determines a wall assembly’s capacity to stop a fire from expanding. Building codes give fire ratings to fire sensitive areas in walls, partitions, roofs, and floor/ceilings
  • ASTM E2257 is a fire test that shows how much the wall and ceiling cause a fire to grow in an area and the possibility of the fire spreading beyond the area, under simulated conditions

Other standards for fire resistance include the NFPA 286: Standard Methods of Fire Tests for Evaluating Contribution of Wall and Ceiling Interior Finish to Room Fire Growth, the NFPA 101: Life Safety Code and ASTM E84: Surface Burning Characteristics of Building Materials.

  • The NFPA 286 is for walls and ceilings and pertains to the testing of materials with fire.The standard shows how much the room’s different elements on the walls and ceilings, including the wallpaper, contribute to the spread of fire
  • The NFPA 101 is the sole document that covers life safety
  • ASTM E84 determines the relative burning behavior of the material by observing its flame spread and smoke density

Moisture - Continuous Insulation

The use of continuous insulation as an additional layer can inhibit a wall’s ability to release trapped moisture from within the wall assembly. The moisture can cause mildew, mold, and rot to develop. Utilizing an air and moisture barrier, along with CI, stops thermal convection (drafts) and thermal conduction and creates a pleasant, comfortable environment for the occupants of the building.

Bautex™ Block Wall Assembly - - - Best Practices for Continuous Insulation

Best practices for continuous insulation in exterior walls should meet, if not exceed, the codes and standards of the ASHRAE 90.1 and 2015 IECC. Exterior walls constructed with continuous insulation should be water, air, and fire resistant.The Bautex Block Wall Assembly meets and surpasses recommendations for best practices for continuous insulation in exterior walls.

  • The Bautex Block Wall System provides an R-14 continuous insulation; far exceeding 2015 IECC recommendations for mass wall assemblies. Measurement of R-value is in accordance with ASTM C 518-10.The Blocks stop thermal bridging and create an insulated and energy efficient building envelope that is compliant with the latest building codes
  • The Bautex Air and Moisture Barrier limits thermal convection by preventing the infiltration of air and moisture to the interior of the structure
  • The Bautex Wall System has an ASTM E119 fire rating of four hours, and ASTM E84 values for flame speed of zero and smoke development of twenty. Since the Blocks meet the ASTM E84 and NFPA 286 they meet the NFPA 101 code

The Bautex Wall System is also easy to install, noise reducing and storm-resistant. Bautex Blocks can be utilized in both commercial and residential buildings and are the ideal choice for best practices for continuous installation in exterior walls. Wrapping a building’s envelope with a layer of CI, along with an air and moisture barrier increases the effective R-value, eliminates thermal convection, and provides for a comfortable indoor environment.