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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 and extremely 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.

It also allows for structural attachment of windows & doors. 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 is available in 7 different depths:
1.0″, 1.5″, 2.0″, 2.5″, 3.0″, 3.5″, 4.0″.

Product Dimensions 


Insulates & Prevents Moisture

Wood bucks don’t insulate, and they don’t keep out water or air. ThermalBuck insulates the mounting points, and acts as a water & air barrier. 

To install ThermalBuck, you’ll need Dow Corning 758 air & weather barrier sealant, and nails that penetrate 1-1/4″ into the structure. Flashing tape is used at the nail flange, and at the transitions of ThermalBuck and the WRB.

ThermalBuck insulates with an R-value range of 4.4 – 17.6, and it also acts as flashing at the rough opening.

Installation Steps



Elastic & Dimensionally Stable

ThermalBuck is dimensionally stable, unlike wood. It won’t warp, shrink, or expand like a wooden buck. Incredibly strong, durable and lightweight, it also offers integrated termite protection.

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

ThermalBuck helps maintain the integrity of the building envelope, and the operating ease of windows and doors. 

Performance Testing