High-performance Insulating Window Buck

If a window isn’t installed properly, it won’t matter how energy efficient it is. Installing windows on a building with exterior insulation isn’t easy. The window and the rigid foam or mineral wool need to line up on the same plane. This is the only way to have good drainage, proper cladding attachment, and to prevent compression of the insulation. Rough openings have always been the weakest spot on any building for air and water infiltration. “Bumping” the window out only makes it more difficult to achieve a good air and water seal.

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 extensive repairs.

ThermalBuck is made up of a type XIV EPS coated in a polyurethane/polyurea blend resin. It is 100% solids, and does not contain vinyl or phthalates. ThermalBuck does not emit VOC’s.

These two elements combined have a compressive strength of 52 psi. Extremely lightweight, strong & durable, ThermalBuck is easy to handle, and withstands loads of 70 lbs. per linear inch.

Window installation with exterior insulation is a challenge. ThermalBuck solves the problems presented by “outsulation” by extending the mounting point for windows & doors to create a flush plane for cladding. This allows for structural attachment of the window.

It insulates the mounting points with an R-value of 4.4 – 17.6. It also acts as an air & water barrier when installed with recommended sealants. This prevents moisture around windows and doors.