Nothing is more frustrating than dealing with a wet or
flooded basement. Wet or moist basements and crawl spaces are sources of high
humidity, which can produce surface condensation, mildew and fungi, musty
odors, and an unhealthful environment for its occupants. Such continuous
moisture can cause deterioration of the foundation mortar, floor joists, beams,
supports, sub flooring, insulation, and electrical-mechanical systems.
Prolonged water around the footer and foundation wall
can soften the soil and weaken its bearing capacity, increasing the possibility
of foundation wall settlement and cracking. Serious seepage under the
foundation footer may erode soil away and cause the wall to drop or crack into
a V-shaped pattern. Excessive moisture can eventually penetrate or wick into
the sub flooring and buckle the flooring or cause warping of the flooring,
making doors and closets difficult to open or close. Since crawl space or
basement dampness always moves toward the drier upstairs areas, higher humidity
will result in costlier heating and air conditioning bills. In the case of
crawl spaces, if the under flooring insulation collects moisture, or sags from
excessive moisture, the heating and air conditioning costs are driven even
higher. Finally, wet basements and crawl spaces reduce the value of the house,
at least by the amount that would be required to repair the damage and to
eliminate the initial cause of the problem. Some homeowners (or Sellers) are
reluctant to discuss or admit their water problem; for fear that the publicity
of an actual or even a perceived problem would reduce the value of their real
estate investment.
Homeowner insurance that fully covers basement flooding
damage is an important means of financial protection to homeowners. Coverage
for wet basements varies from state to state and company to company. But
typically, the damage from water seeping in from the outside or backing up from
the sewer is not covered by standard homeowner policies. In some cases, special
coverage can be purchased to cover these risks, but it is usually very limited
in the types of personal property it covers and amounts of coverage that may be
purchased.
It is up to each homeowner to know how to prevent water
damage before it starts. This can be done through proper home maintenance and
installation of systems intended to remove or divert water before it is even
allowed to get anywhere near the basement cavity. Trust me, I live in a flood
zone and I do not get a drop of water from those three or four day rains. I
simply purchased my flood zone home, analyzed the situation and properly
corrected the existing issues. I performed thousands of home inspections and
observed hundreds of flooded basements, so I enjoy showing homeowners how to
alleviate the moisture accumulation in and around their home.
CAUSE OF WET BASEMENTS AND CRAWLSPACES
Most wet basements or crawl spaces are caused by surface
water accumulating around your home, which is not adequately drained away from
the exterior foundation wall. This water accumulation will simply cause puddling
next to your home and eventually this saturated area will have nowhere else to
drain to except down into your basement or crawl space.
Sources of this water include the following:
-Roof water, if no gutters and downspouts are presently
installed to convey roof water away from your home.
-Roof water, if your gutters leak at the seams or
overflow because of clogging from leaves and bird nests.
-Roof water, if the downspouts (leaders) are clogged or
do not have sufficient means at their outlets to drain water out and away from
the foundation wall. Frequently, a downspout ends right at the corner of the
house without an elbow and a 4-6 foot extension to carry roof water away from
the foundation, leaving roof water to concentrate at that outlet point and seep
right into the soil next to the foundation wall. A typical 2000 square foot
roof can produce almost 1250 gallons of water during just 1 inch of rainfall.
If the rainfall is steady and prolonged for days, the opportunity for this roof
water to saturate into the ground next to the foundation wall is high.
-Excessive watering of flower beds and shrubbery around
the foundation wall. Once the upper soil layer or mulch bed air spaces are
filled with water, the excess water either runs off or seeps into the ground
next to the wall. Prolonged and excessive watering can contribute to a large
amount of water accumulation next to basements walls.
-Rainwater runoff from any adjacent lawn areas that are
getting saturated, improperly sloped driveway or walkway areas if the
landscaping forces water to drain toward the house instead of away. If surface
runoff is directed toward your foundation wall, this water will pond and
eventually soak into the soil, thus becoming a potential source of basement or
crawl space water. Downspout splash pads are not very effective if they drain
onto a backward-draining slope toward the foundation wall. I consider these
splash pads useless.
-Subsurface or excessive groundwater may be intercepted
or dammed up by a basement or foundation wall. Houses which are built next to a
down slope on or at the base of hillsides are particularly vulnerable since
there is greater opportunity for surface water to saturate the hillside soil
and then flow heavily downhill and become groundwater next to your foundation.
Foundation walls act like dams and can intercept and trap this subsurface
water, causing pressure build-up on the outside and forcing water through
joints and cracks in basement walls or cause seepage under the foundation
footer leading to a high water table that will seep up through your concrete
floor.
-Nearby springs may have been filled in or covered up by
the developer. Unless the springs were properly drained away from the lot or
subdivision, such water will eventually seep into the surrounding fill, become
a pool of groundwater, and eventually get deeper and cause the accumulating
water to spread out onto neighboring properties and force itself laterally and
upwardly into basements and crawl spaces.
-Nearby creeks may overflow during a heavy storm runoff
and either directly flood basement or crawl space areas, or contribute to
accumulating groundwater, which may become sufficiently high enough to cause
seepage into the basement or crawl space area. Homeowners may not experience
the effects of groundwater seepage or overflowing creeks for months or years
after purchasing a house because of drought or infrequent out-of-bank flooding.
However, when such conditions do occur, they may come suddenly without warning
and cause serious problems after the builders warranty period has already
expired.
-Improperly installed, clogged, collapsed, or leaky
drains may not allow downspout water or foundation wall water to escape.
Perimeter, footer, or foundation drains are installed around the exterior of a
house below the basement floor to intercept and dispose of subsurface water to
eliminate groundwater build-up and seepage under the house. If these drains are
improperly installed or become clogged with silt or roots, they will not
operate as intended. Sometimes an otherwise good perimeter drain gets covered
up at its end(s) during the final backfilling or landscaping stages of
construction and the intercepted water has no place to go but to build up
behind the foundation wall and eventually seep into the basement or crawl
space.
-Underground drains leading away from downspouts may not
have sufficient slope to carry water away; may empty into the adjacent lawn and
get covered with topsoil; may become crushed during landscaping or become
pinched at their outlets; or may lead to an area which ponds and backs up
accumulating water. The end result in all these cases is leakage or overflowing
at the bottom of the downspout and water penetrating the foundation area.
-Soil continuously draws water up from subsurface
groundwater sources in a crawl space like a blotter by a mechanism known as
capillary attraction. The finer the soil (e.g. clays), the more aggressive the
capillary pumping action. As the water rises to the surface, it evaporates into
the crawl space. Such ground moisture can be a significant source of dampness
and humidity under a house, even without standing water. The presence of
capillary water is often indicated by a whitish residue, left on the ground
surface of the crawl spaces, resulting from evaporation of water containing
minerals and salts. Lack of a moisture barrier, such as plastic sheet, will
allow this capillary action and evaporation to contribute almost unlimited
moisture sources to crawl space areas.
DRYING OUT A WET BASEMENT
If you have water running into your basement, the first
thing to do is to see if it occurs immediately after a rain. If this is the
case, it is probably due to surface water puddling against the outside of the
basement walls. This is the most common source of basement water problems and
one that you may be able to fix yourself.
First of all, you need to locate the source of entry. I
suggest you look for ways exterior run-off water can enter into this area in
the basement. Make sure downspout runoff isn't pooling or percolating into soil
near the foundation during a storm, and that gutter and downspout seams aren't
leaking. Gutters should be catching the rain and channeling it to the
downspouts. Make sure there is no debris blocking the inlet of the downspout
and preventing water from escaping down the spout. The downspouts should have
extensions so that they discharge the water at least five feet away from the
house.
Check the ground outside your foundation. Unfortunately,
the earth that was used to back fill around most foundations settles over the
years so it is extremely common for earth near the house to be lower than the
rest of the yard. All grading should slope away from your house at least 1 inch
vertically for every 1 foot of horizontal travel. If earth is already near the
top of the foundation or if your lot slopes toward the house on one side, you
may need to use another approach. In this case, establish a swale or shallow
ditch on that side of the house to intercept the surface water and carry it
around the house and down slope toward the street. Place the drainage path as
far from the house as possible. If you have enough space, the ditch can easily
be made less noticeable by blending it into the lawn.
If you have pavement immediately next to the house, be
sure it slopes away. If a driveway or sidewalk is either extremely flat or
slopes toward the house you have several choices. You can replace the pavement
and correct the grade in the process. If it is concrete, you can have it mud
jacked (raised), which usually costs about half as much as replacing the
concrete. You can also add an additional layer of pavement next to the house to
reverse the slope. If you do the latter, you will also need to caulk joints and
cracks in the drive or sidewalk so that water which pools on the surface
doesn't penetrate and end up in the basement.
Window wells are another common source of basement water
problems. The window well itself should be much deeper than the window sill to
provide a place to catch rain that might fall into it. The top rim should be 3
to 4" above grade with the ground sloping away so that water is not
channeled into the window well. If the window well is on a side of the house
where wind drives rain or ice against the house, installing a plastic bubble
cover over the well will help keep rain, leaves and snow out.
Fixing any grading related problems such as those
mentioned here will take care of the majority of basement water problems and
should always be done first, even if you are considering other measures such as
repairing a leaky crack in a Poured Concrete foundation They will bond your
crack surfaces together by injecting a specially formulated epoxy material that
will stop water from leaking into your basement. This process closes the crack
and restores the structural integrity of the wall by producing a "weld"
that is equal to the original concrete in strength and performance. Some
companies will offer a ten year warranty.
SEVERE FLOODING IN BASEMENTS (Waterproofing)
In my humble opinion, "water proofing"
systems, especially those on the exterior of a building should be used only as
a last resort. Many waterproofing systems involve water collection and
discharge and are very costly. If you've tried all my recommendations and water
is still gushing into your basement, and you can not resolve this, I recommend
that you call in a professional. Otherwise, consider an interior gutter. This
dam-and-channel system goes around the perimeter of the basement floor and
collects water that flows down or through the walls or floor, routing it to a
floor drain or sump pump.