Treenail

[2] Treenails are extremely economical and readily available, making them a common early building material.

Traditionally treenails and pegs were made by splitting bolts of wood with a froe and shaping them with a drawknife on a shaving horse.

Each roughly-shaped bolt of wood is placed above the sharp end of the pipe and hit with a wooden mallet, but not hard enough that the mallet hits the sharp edge of the pipe; the next billet drives the preceding one the rest of the way through, and it falls through a hole in the bench into a bucket.

After treenails are hammered into the mortise, they can be trimmed, split, and wedged with a small piece of oak that increases friction force.

[8] As an alternative to the wedge, the treenail can receive a plug or a punch to the center that expands the entire circumference.

While this method prevents leaks by reducing gaps, plugs and punches are more likely to fall out in cold temperatures.

When used in a truss, the connecting mortises are drilled off center such that when the treenail is inserted it creates a tighter joint.

They had the advantage of not giving rise to "nail-sickness", a term for decay accelerated and concentrated around metal fasteners.