Use Spirit Level Frequently
You are now ready to start erection of the walls. Make frequent and careful use of the plumb line and spirit level in this work. Without constant checking the walls have a way of going off at odd tangents.
The simplest and least difficult style of fitting logs is the “saddle and notch,” in which the logs are given a rough notch and laid together without special fitting or trimming. The spaces are later caulked with oakum. While this is the simplest method, it is the poorest from the standpoint of weather tightness.
Four methods of notching logs.
Another and better method is the same as above except that the notches are so carefully cut that the logs fit closely and must be hewn down along two sides to provide neatly joined surfaces. This also will require some caulking but not as much. It is customary to lay a strip of oakum between all logs, regardless of the style of fitting.