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2021 IECC Window Detail: CMU Wall with EIFs

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2021 IECC Window Detail: CMU Wall with EIFs
Courtesy Of
BSC

Notes

Window Detail 1 - CMU Wall with EIFS

  • Note: Always follow the window manufacturer’s installation guidance. Not following manufacturer guidance may void the warranty.
  • This is a “drained wall”. The block wall is insulated on the exterior with an exterior insulation and finish system (EIFS) adhered to a fluid-applied water control layer or water-resistant barrier (WRB). Drainage occurs between the rigid insulation and the WRB. This is achieved by installing the rigid insulation using thick vertical beads of EIFS adhesive, creating a small gap between the insulation and the WRB. The EIFS insulation layer can be expanded polystyrene (EPS) or extruded polystyrene (XPS).
  • The window openings are drained to the fluid-applied water control layer (WRB).
  • The wood frame (“window buck”) extends outwards to the exterior face of the exterior insulation and is coated with the same fluid-applied water control layer as the exterior face of the CMU. The fluid-applied water control layer is applied to the wood frame inwards at least past the point where the interior air seal is located around all sides of the frame. This creates water-resistant surfaces inside the cavity between the window flanges and the interior air seal, in case any water gets behind the flanges. The head and jamb window flanges are flashed to this water control layer using a self-adhered flashing membrane. The sill window flange is not flashed, to allow any water that may get behind the flanges to escape.
  • Note the gap between the EIFS head trim and the rigid head flashing. This gap allows water to drain and allows the bottom of the trim to dry out more easily. If installed without this gap, capillary action can draw water into the tight space between the head trim and the rigid head flashing.
  • Backer rod for the interior air sealant should be installed after the window is installed, leveled, and shimmed. Use correctly sized backer rod.
Window Drawing image + notes (png) (691.64 KB)
Window Drawing + notes (tabloid pdf) (569.64 KB)
Window Drawing + notes (portrait pdf) (573.32 KB)

Disclaimer

This content is a work created with funding provided by the United States Department of Energy under Contract no DE-AC05-076RL01830 for the operation of Pacific Northwest National Laboratory. The information and guidance provided by Pacific Northwest National Laboratory (PNNL) in the content are intended solely for educational purposes only and do not constitute formal training or certification. It is provided with the explicit understanding that neither the United States Government nor the United States Department of Energy, nor the Contractor, nor any or their employees, nor any jurisdiction or organization that has cooperated in the development of these materials, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness or any information, apparatus, product, software, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof, or Battelle Memorial Institute. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof. Viewers assumes full responsibility for all actions that they may take from information provided in this content including ensuring the safety, code compliance, and proper functionality of any products they choose to install. Installation and use of such products should be performed in accordance with local regulations and manufacturer instructions.