root system generally extends out as far as the drip line (outer edge
of branches). If the branches overhang the roof, then the roots probably
extend under the foundation. They will draw water out, and the soil
will shrink unless moisture can be maintained.
placed close against the house, their roots draw water from under
the foundation and allow the soil to shrink; but overwatering can
water does not drain away from the house or puddles stand close to
the house after a rain, the soil will swell in the areas that stay
wet. Areas that do not get enough moisture will shrink.
or breaks in the lines could add enough moisture to cause swelling
or erosion in the surrounding soil.
or leaks as well as excessive splashing or spraying can affect the
surrounding areas causing swelling of the soil.
can interfere with the normal flow of water runoff and cause excessive
moisture to accumulate in one area while keeping another area too
thin slabs of concrete or other materials exclude moisture from the
underlying soil. If close to the building, they rob the foundation
of needed moisture and allow shrinking. However, other areas may be
kept wet due to runoff from these surfaces.
or snow on the roof is collected and transported to downspouts which
direct the water into drains or outflow on the surface. The outflow
should be directed at least three feet from the house to avoid foundation
problems, and the runoff should be directed away from the house.
Causes Due to Mother Nature
a number of known fault zones in different areas of the country.
Along these zones one side shifts with reference to the other. This
can tear up streets, sidewalks, driveways, pools, homes, and buildings.
Faults have been mapped, and builders are careful to avoid them.
Excessive withdrawal of well water and heavy construction are responsible
for movement along these zones.
periods without adequate rainfall and unusually hot summers upset
the natural balance of moisture in the soil. The homeowner can restore
the balance by properly watering during these periods. However,
too much watering also upsets the balance. Local governments sometimes
restrict the watering of lawns to conserve drinking water supplies.
that cannot be carried off by natural and man-made drainage create
the same problems caused by overwatering.