Civil Engineering Reference
In-Depth Information
footings. So if you plan only a support column at each
corner, you need more footing to be safe.
Fortunately, unless they built on creek bottom land,
most of the mountain settlers found, only inches
down, very rocky, firm subsoil that really resisted
settling of any kind. This soil allows for a minimal
footing, and will let you get past the slow, nonvisible
stage of building sooner and on to the good stuff with
the logs.
A continuous foundation for a log house just isn't
necessary (although most building codes require it).
The logs act as massive beams to distribute the weight
of the house evenly, so support can be at wide inter-
vals. The benefits of a continuous foundation do
include a way to keep winter blasts from under the
floor. And it's hard for mice and other creatures to
steal your insulation.
Muskrat Murphy's cabin foundation near Hilda,
Missouri, is continuous, laid on a steel-reinforced,
foot-wide concrete footing below the frost line, with
ventilation on all four sides. Most building codes do
not require the reinforcing rod, and only specify vents
front and back, within three feet of each corner. The
screened vents are closed in cold weather.
But there's good storage under there, and the floor
stays warmer in winter.
We build workshops and storage buildings simply
on 3-foot corner angles of 12-inch-wide stones, laid
flat on just enough concrete below frost line to give
even support. We'll usually build another set of piers
midway from the front and back walls, too, if the
house is over 16 feet long. There's sometimes an addi-
tional pier supporting a sleeper under the floor joists,
halfway down the sides. This also gives support to the
walls midway, which is a good idea if your cabin is
more than about 18 feet deep.
In yet another variation, we will build on stone cor-
ner piers set on reinforced footings for owners who
want to fill in a continuous foundation later. We dig
and pour a footing all the way for their later use.
Filling in between corners is a simple matter of lay-
ing stone up from a below-frost trench till it reaches
the bottom of the sill logs. The fill-in carries little
weight, but seals out weather and creatures. It can be
done a little at a time as you collect stone, and it some-
times happens that the house itself is almost complete
before the foundation. We did the Bennett Alford
house in Nelson County, Virginia, this way, which was
later filled in with stone from their woods.
The log house my family and I live in has a contin-
uous foundation because we have a flagstone floor set
on fill, with the logs being 18 inches up from floor
level. There is a reinforced footing because we hit solid
rock in places, and natural, uneven settling of the
house would crack the footings and foundation.
For your own purposes, you should build a longer,
wider foundation for softer ground, laid on a rein-
forced footing. Of course you should use stone, if pos-
This cross section shows the reinforced concrete footing, stone
foundation, and the sill log laid on a metal flashing termite shield.
Floor joists were traditionally mortised into this sill.
When laying out footings, allow extra space so that the foundation
wall is centered on them. Foundation corners with midwall support
are structurally sufficient for a log house, but building codes may
require a continuous foundation like this one.
