Drip Kerf - Home And Stairway Building

A drip kerf is a notch cut underneath the bottom of a piece of wood that protrudes or extends from a section or part of a stairway or building. A good example of this would be the picture below.

The drip kerf was cut underneath this stair tread. Now, you're probably wondering why you would need to cut a drip kerf into anything.

If this notch wasn't there, water or moisture could actually roll underneath the stair treads. The water could roll past any gaps between the top of the stair riser and the bottom of the tread.

After the moisture reaches the interior stair framing, it can attract termites, cause wood rot and wreak havoc on the stairway. The drip kerf usually prevents any moisture from rolling past it.

Carpenters have been notching posts, beams and even stair treads for years, possibly centuries, to prevent water from damaging the rest of the house. Obviously, there would be no need to cut a drip kerf on anything that wasn't going to be exposed to moisture. In other words, they wouldn't be used on the interior of a building.


Stairs / Stair Glossary

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