In laying the successive rounds of logs in the walls, several details
must be observed to keep them lined up so that the top logs form a
level seat for the roof framing. The corners should be kept as level as
possible as each round is laid. This can be done by measuring vertically
from the top of the floor joists, from time to time, as a check. A
variation of 1 inch in height will not cause a serious difficulty.
The height of the corner's is regulated in two ways: (1) By increasing or
decreasing the depth of the notch, and (2) by reversing the top and butt
ends of the logs when laying them in the wall.
The logs should be fitted together as tightly as possible. In the case
of somewhat irregularly surfaced logs, it may be necessary to smooth off
certain portions of the under side of the upper log to secure a tight
fit. Only in exceptional instances, however, should this be done to the
top of the lower log.
The face of the logs on the inside of the building must be kept plumb,
that is, in the same vertical plane. An ordinary carpenter's, or spirit,
level may be used, but a 6- to 8-foot plumb board is considered most
satisfactory because of its greater length.
The logs should be pinned together with a wooden pin or large spike (fig.
11). Spiking is done by boring a 3/4-inch hole halfway through the upper
log and continuing with a 7/16-inch hole through the bottom half. Then
drive a 10- or 12-inch spike into place, or until it penetrates half the
next log below. The spikes should be staggered in alternate rounds or
tiers of logs. If wooden pins are used, fir or oak logs are preferable.
Neither wooden pins nor spikes, however, offer interference to the
settling of the walls.
[Illustration: Figure 10.--Framing floor joists.]
The spike method is easier and quicker, and just as satisfactory as
the wooden pin. The logs should be pinned approximately 2 feet from
each corner and at each side of the window and door openings. For small
structures, where the alignment of the walls is not so important, pinning
may be eliminated, but it is essential to align larger buildings
accurately in order to prevent individual logs from springing out of
place.
[Illustration: Figure 11.--Pinning logs together.]
Where the use of logs having a decided curve, or sweep, is unavoidable
they should be set in the wall with the bow or back up. Such logs may
be straightened by making enough saw cuts in the upper side of the
curved surface to allow them to straighten out. The cuts should be
from one-third to one-half the depth of the log, or slightly more, if
necessary (fig. 12).
[Illustration: Figure 12.--Straightening a curved log.]