Continuous Exterior Insulation with InSoFast's X-Bracket Batts - High Performance "Outsulation"

Have you heard the term “outsulation,” to refer to continuous exterior insulation (CI)?  If not, you likely soon will!  In this video, Green Builder Matt Hoots of Sawhorse, Inc. checks out InSoFast’s Batt-Brackets, an exterior X Bracket system for high performance wall assemblies that combines continuous insulation using batts with interior cavity insulation. 

Continuous insulation on the outside of homes can significantly improve thermal control, moisture risk, and comfort.  Continuous insulation is, as the name suggests, uninterrupted across the entire building envelope, or the boundary between conditioned interior space and the exterior.  Continuous insulation reduces thermal bridging, when energy leaks through building materials that are more conductive, such as wood or metal studs.  Fewer energy leaks mean less energy consumption and lower energy bills.  Basically, thermal leaks occur when insulation is interrupted.  Interior installation is typically interrupted by studs and building penetrations, and this is one reason that exterior insulation, typically in addition to interior insulation, can be a better fit for some projects, particularly in colder climates and for high performance buildings, new buildings, and for major exterior renovations.

All structures have some thermal bridging, but a key thermal control goal is to minimize and control this energy loss.  Continuous exterior insulation provides many benefits over traditional insulating practices, including:

• Reduces heat loss due to thermal bridging
• Improves energy efficiency, reduces heating and cooling loads
• Lowers condensation risk in cold climates
• Helps with air sealing and draft reduction
• Facilitates drying to prevent mold and mildew (*not necessarily with foam)
• Improves comfort by helping to maintain consistent temperatures throughout a building
• Extends the lifespan of structures, especially wall components 
• Can improve noise levels 
• Will increasingly be important to meeting modern energy codes and building standards
  
  

X-Bracket systems contribute to all four primary building control layers—providing thermal control and supporting air, vapor, and water control—when incorporated into a properly detailed wall assembly. As such, they can serve as part of a high-performance enclosure approach developed/popularized by Joseph Lstiburek and colleagues, often described as a “perfect wall.

InSoFast already offered easy-to-use X-Bracket systems for interior insulation and for rigid and spray foam exterior applications.  All of the exterior X-Brackets provide a sturdy attachment point for furring strips and significantly reduce heat conduction compared to wood furring strips, helping to optimize insulation efficiency. They also contain built-in cross-ventilated rainscreen channels with an air gap, a drainage path, and ventilation for drying.  Ease of installation is another advantage, making the system accessible across a range of projects and skill levels.  The exterior X-Bracket system uses standard long structural screws, requiring no new tools or supplies for installation. 

The newer exterior X-Bracket batt system is designed as the name suggests for use with lower cost batt insulation, and this is the real innovation with this product. The brackets create a structure and solid means for attaching softer batt insulation, importantly without the risk of compression or sagging.  Where can exterior X-bracket batt insulation shine? As mentioned, batts can be significantly cheaper than rigid board insulation. They can be simpler from a materials standpoint and generally easier to install, though they must be installed correctly.   And finally and importantly, people and project teams with goals to avoid petroleum-based spray foam may well find stone wool batts a preferable, more sustainable material.  

Note that InSoFast does not recommend using exterior batt insulation in conditions where it could be exposed to water or insufficiently protected, as batt materials are more sensitive to moisture and rely on proper enclosure detailing for durability. So the system relies on keeping bulk water off batts, or performance will be negatively affected.  Good installation and detailing are key; the cladding and water-resistive barrier (WRB) must do their jobs. 

Have you worked with the X-Bracket exterior batt system?  We’d love to hear all about it and to learn about your project and experience!