Kesternich test—Simulates acid rain conditions by subjecting samples to a sulfur dioxide atmosphere as well as condensing moisture.

Kick-out (Elbow)—(Turn-Out)— A lower downspout section used to direct water away from a wall.

KIP (kilopound)—A unit measure equal to 1,000 pounds of force (4.4kN).

Knee—The connecting area of a column and rafter of a structural frame such as a rigid frame.