Water in the Basement
SEPTEMBER 2001 by John R. Berry, PE Home Inspector When buyers consider a house for purchase, one of the
important "must haves" is a dry basement. Often, buyers are turned off by a damp smell; black mildew
stains on the foundation walls, water stains or the presence of water. It's no wonder. Damp basements can be expensive to correct. The grapevine is full of horror stories,
and some waterproofing companies get rich performing needless modifications
for naive homeowners. In my experience, the vast
majority of basement water problems can be corrected inexpensively by the
homeowner. Water usually gets inside
because of something on the outside.
The usual suspects are: - Downspouts discharge
rainwater next to the foundation. The
remedy for this is to attach a downspout extension to the bottom of the
downspout so water is discharged four or more feet from the foundation. - The soil next to the
foundation is too porous, or is sloped so water runs towards the foundation. The remedy is to replace about 6 inches of
the porous soil with clay-rich dirt, and add more such dirt in a sloping
fashion so water runs away from the house. |
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SERVICES
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John R. Berry is a home inspector for Boswell
Building Surveys in Baltimore, MD. 410-243-0300 ·
30 years experience in engineering and construction. ·
6 years of property inspection experience (residential,
multi-family & commercial) ·
Bachelors degree in Mechanical Engineering ·
Licensed Professional Engineer ·
Masters degree in Business Administration ·
6 years experience in property renovation & home
improvement |
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- Small leaks appear in
the foundation wall or at its joint with the floor due to imperfections or
small cracks in the wall. These are
often remedied by gouging-out the crack or hole so a thick patch of hydraulic
cement can be applied. (This type of cement works so well, it will set-up in
an active leak). Sometimes when water
is stopped at one location, it will find another way in. Therefore, the patching process may
continue in several steps or over a period of several rains. When all the leaks are patched, apply a
coat of water-sealing paint to the walls. The paint will not only provide a
barrier against minor seeping or wicking, but the basement will look brighter
and smell fresher, too. (Very long and/or wide cracks in a foundation wall
are indicative of potentially serious settling or soil pressure
problems. These types of structural
problems must be corrected first or the water leaks will recur.) If the house sits on the
downside of a hill, and the builder has not graded a diversion swale into the
yard, water problems can occur. In
this case, adding clay soil next to the house, as described above, may help. That should be tried first. If that does not correct the problem,
other more expensive remedies may be required. The two common remedies in this case are: - Create a swale or ditch
to carry the water around the house, or - Install a drain line to
carry the water around. Drain lines
usually consist of a 4-inch diameter perforated plastic pipe (wrapped in
plastic cloth to keep silt out of the pipe) laid in a sloping gravel trench
underground. A less desirable
alternative is a french drain, which is an underground gravel-filled trench
without the plastic pipe. If all the above efforts
fail, it may be because an underground spring is flowing under or near the
house. A very expensive waterproofing
system may therefore be necessary. This
consists of digging up the perimeter of the basement and installing a
perforated drain line in a gravel trench.
The drain line drains the water into a sump and is pumped-out into the
yard. Be sure the pumped water is
discharged far enough from the foundation and in such a manner that the
discharged water does not run back against the house again. As a further precaution, a 4-inch high,
corrugated plastic skirt may be installed against the wall and connected to
the drain trench around the basement.
The skirt will catch any water leaking through the wall and direct it
into the trench, thus keeping the floor dry.
Moisture will still be on the wall, so it is important not to trap
that evaporating moisture with a finished wall on the inside of the basement. ©2000, 2001, 2002 Quarry-Pyramid,
Inc. |
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