Civil Engineering Reference
In-Depth Information
CHAPTER SEVEN
laying wood and stone
on the ground to
start a log house was one of the things our pioneer
forebears just weren't very good at. Invariably, sill logs
were put too close to the soil, or right on it, which
explains why so few pine cabins have survived, even
with restoration. Termites love pine. And pine, oak, or
even the long-lasting woods such as cedar, chestnut,
and walnut eventually rot, and it happens soonest
close to the damp earth.
Even stones laid on top of the ground, in a row
beneath the logs with no footing in the ground, will
give good support if there are enough of them,
because, of course, each is carrying less weight and the
total load is spread over more area.
Footing and Foundation
A house footing is the “foundation for the foundation.”
For a continuous foundation, the old builder's rule
says the footing ditch should be twice the width of the
wall thickness and at a depth below frost line. Even
slender columns of stone at the house corners would
be enough to resist settling, if laid on wide concrete
Early Foundations
Many of the settlers' cabins were on hillsides, so only
the uphill sills were on or near the earth, and maybe
the ends of the first side logs. Those that were high off
the ground lasted the longest, so take a lesson from
that. It usually means a high floor, but it is worth it
after a few soggy seasons. And building codes require
18 inches or more crawl space for plumbing, wiring,
and insulation.
Some pioneers did build high to begin with, but the
weight of the house, concentrated on a small area of
foundation stones at each corner, eventually drove the
stones into the ground, lowering the whole house.
Certainly much of the sag and tilt of old log houses is
due to this settling rather than to poor workmanship
in the house itself.
Too few early builders put up a wide, heavy foun-
dation. Most stacked flat stones singly, achieving a
teetery column with maybe rock chips wedged into the
cracks. Some cabins had pieces of metal from broken
plow points wedged between the stones to give the
piers stability.
This drystone foundation was built for the restoration of the Sam
Black tavern. The unmortared granite duplicated the original.
