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The High-Performance Building Envelope

For years architects and builders have struggled to solve multiple problems with window installation, particularly when coupled with rigid exterior insulation and/or rainscreens. Rough openings are the weakest spot for potential water and moisture damage in any building.

ThermalBuck solves a number of common issues that wooden bucks and rigid insulation introduce, and simplifies the installation of windows & doors. It improves the water & air seal at the rough opening, and insulates the mounting points of windows & doors.

Dimensionally stable, it won’t warp, shrink, or expand like a wooden buck. Lightweight, flexible, and strong, it is easy to install with one person.


Extends the Mounting Point

ThermalBuck extends the mounting point of windows & doors to meet the exterior insulation plane and/or rainscreen, and creates a flush plane for exterior cladding.

ThermalBuck is available in 7 different depths: 1.0″, 1.5″, 2.0″, 2.5″, 3.0″, 3.5″, 4.0″.

Product Dimensions 

Samples & Distribution


Insulates & Prevents Moisture

ThermalBuck insulates the mounting points, and acts as a water & air barrier (when installed with approved sealants). No need for flexible flashing tape when you use ThermalBuck – the coating is waterproof, and the rough opening is sealed when installed with DAP Dynaflex 800 Modified Polymer Sealant. 2″ galvanized roofing nails go through the 1/2″ tongue, penetrating a min of 1-1/4″ into the structure. Flashing tape is used at the nail flange, and the transitions of ThermalBuck and the WRB.

ThermalBuck insulates with an R-value range of 4.4 – 17.6.

Installation Steps


Strong, Elastic & Dimensionally Stable

ThermalBuck is dimensionally stable, unlike wood. It won’t warp, shrink, or expand like a wooden buck. Strong, durable and lightweight, it’s cut to fit on site with a miter saw, and installs simply with a nail gun. With a compressive strength of 52 psi, it can handle hurricane force winds with minimal permanent compression. Shear strength is 70 lbs. per linear inch.

ThermalBuck helps maintain the integrity of the window installation, and the operating ease of windows and doors. 

Performance Testing




Structural Attachment for Windows & Doors 

ThermalBuck allows for structural attachment of windows & doors. Sealant is applied to the underside, then 2″ roofing nails are driven through the 1/2″ tongue into the rough opening. Once the window is set into place, screws for the nail flange must penetrate through ThermalBuck a minimum of 1-1/4″ into the structure. 

Architects and builders know all too well – if windows and doors aren’t mounted properly, it won’t matter how energy efficient they are.

Installation Videos