What Is a Wood Buck on a Window?

During construction of a building, builders must leave openings in the walls for the later installation of windows. These openings are lined with frames called bucks. Wood is the material traditionally used to build bucks. A wood buck on a window is a wood frame that was set into the wall to define the space for window installation.

Bucks define the space for windows during construction.

Constructing a Wood Buck

You can make a wood buck in three ways, according to ICF Builder Magazine. The first, and most common, option is the external buck. The ends of the buck are placed flush with both faces of the wall using a frame of 1 by 4s attached to both sides of the buck to fasten the buck to the wall. The second option is an internal buck cut to the width of the opening in the wall and secured with long drywall screws. The third option is a combination of the first two.

Bucks in Concrete

Wood bucks installed in concrete walls or bucks that might touch concrete need to be made from pressure-treated wood or separated from the concrete by a waterproof material.


ICF Builder Magazine offers the following tips for building bucks. Use hot-dipped galvanized nails as fasteners because the lumber might corrode other fasteners. Hammer the nails to the outside of the buck about every three inches. If the window opening is larger than three feet either horizontally or vertically, prevent bowing by bracing the buck every two feet. If the buck is large, help lift and position the sill on the wall by fastening blocks to the sill.


Although wood is the traditional material for bucks, builders are increasingly using vinyl for bucks, according to ICF Builder Magazine. Vinyl bucks are lightweight, are easy and quick to assemble, cannot burn or fuel a fire and are not subject to termite or mold damage. However, vinyl usually costs more than wood.