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 90.12013 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.