The high performance window mounting system for continuous insulation.

ThermalBuck™ solves the challenge of installing nail flange windows & doors with exterior insulation by extending the mounting point to create a flush plane for cladding. It also insulates the rough opening, limiting thermal bridging around windows & doors.


Coated with a waterproof resin and secured to the rough opening with an air & water barrier sealant* and nails, it’s simple to install and easier to flash than a wood buck. Dimensionally stable and strong, it will not warp, rot, or shrink, and helps to support the weight of the window. ThermalBuck™ outperforms a traditional wood buck, and protects the integrity of your window & door installation.

*We recommend ThermalBuck™ installation with tested & approved sealants.  See our FAQ page under “Sealants” for more information.

7th generation Missouri homebuilder Rusty MacLachlan, J.R. MacLachlan Custom Homes & Remodeling 

If a window isn’t installed properly, it won’t matter how energy efficient it is.

Traditionally, a wood buck is built to extend the mounting point of the window to create a flush plane. But wood can rot, warp, and shrink over time. Wood is a poor insulator, allowing thermal bridging around each window and door. Not only does it reduce the energy efficiency of the building, it causes condensation to form, and potential damage from moisture—which can lead to expensive repairs.


Austin builder Matt Risinger features ThermalBuck on an episode or Risinger Goes Rogue

“Once you see it, you really understand the problem this solves for builders like me.”

 – Matt Risinger, Builder, Building Science Expert, Risinger & Co., Austin, TX

How to Install a Window with Exterior Insulation

Introducing the ThermalTight™ System

ThermalTight™ makes it possible to manage water – air – vapor + thermal all in one panel, with one less trip around the building envelope. It combines two essential building envelope materials into one, easy-to-install panel: Neopor® GPS semi-vapor permeable rigid insulation by BASF, and a high-performance WRB laminated to the exterior of the panel, that acts as both a water and air barrier.

This is the future of the building envelope. 

Learn more at