A dry basement
for work, hobbies, storage, and extra living space is an asset to any
home. On the other hand, a wet, damp, musty basement taints the value
of the entire house as an investment, and is a source of continuing
annoyance and frustration for a homeowner.
The best general advice to anyone attempting to eliminate unwanted
water from a basement is that all cures and options should be fully
researched.
A homeowner who examines the full range of possible causes and
potential remedies will be far more likely to obtain effective and
lasting repairs than one who settles for the first, easiest, or least
expensive method proposed as a solution.
Look For Obvious Solutions
The cause of a wet or damp basement can be minor, readily apparent, and
easily corrected. Here are some probable causes and possible solutions:
- Problem: The source of water in the basement can not
be identified.
Solution: To determine whether the water is seeping in
from the outside or condensing inside, tape a twelve-inch square of
aluminum foil to a wall that is prone to dampness, sealing all four
sides as airtight as possible. In a day or two, if the side of the foil
that was against the wall is wet, the problem is seepage. If the
outside is wet, it's condensation.
- Problem:
Lawns that are flat or slope toward the house permit surface water
(rain and melting snow) to drain down against basement walls. Water
enters through cracks or other openings in the walls and causes wet
spots on the walls or standing water on the floor.
Solution:
Slope the ground away from the outside foundation (about one inch per
foot). Extend the slope for at least ten feet. Seed it with a good lawn
grass. Sodding is a common practice and prevents the washing away of
newly graded areas during heavy rains.
Where a large area of
land slopes toward the house, surface drainage should be intercepted
and redirected some distance from the house. Dig a shallow, half-round
drainage ditch or depression designed to route the water around the
house. Sod the ditch or plant grass in it. If even a shallow ditch is
objectionable, drainage tiles, with one or more catch basins at low
spots, may be installed.
- Problem: Defective, clogged, or
nonexistent gutters and downspouts allow roof water to form puddles, or
wet soil near or against basement walls, and enter through cracks or
openings in the masonry.
Solution: Install gutters and
downspouts wherever needed. Keep them free of debris. Where leaves and
twigs from nearby trees may collect in a gutter, install a
basket-shaped wire strainer over the downspout outlet or place
screening across the length of the gutter. Repair gutters and
downspouts as soon as the need appears.
To prevent concentration of water at the point of discharge, use a
concrete gutter or splash block to carry the water away at a slope of
one inch per foot. Also, consider extending downspouts from rain
gutters away from the outside foundation.
Roof water can also be piped underground to a storm drain, dry well, or surface outlet fifteen feet or more from the house.
- Problem:
Dense shrubbery and other plantings around the basement walls prevent
good ventilation.
Solution: Trim heavy growths of shrubbery so that
soil gets more sunlight and dries quicker. When digging up the
plantings, remove any pieces of masonry, mortar, or other material
buried near the house after the basement was excavated.
- Problem:
Unprotected basement window wells act like cisterns during heavy
storms, permitting water to seep in around window frames and below
windows.
Solution: Windows or parts of windows below grade should be
protected by metal or masonry window wells, with bottoms consisting of
gravel to permit good drainage. Clear plastic bubbles are available to
cover the entire window well like an awning.
- Problem:
Atmospheric moisture produces condensation ("sweating") on cool
surfaces in the basement, particularly walls, floors, and cold water
pipes.
Solution: Insulate the water pipes. Promote good
ventilation--sunlight and free movement of air can quickly dry out a
basement. Ventilation should be regulated according to the weather
conditions. During hot, humid weather or long rainy spells, windows
should be closed because the outside air will probably contain more
moisture than the basement air. Heat the basement during the winter.
During hot weather, use air conditioning to cool and dehumidify the
air.
- Problem: Leaky plumbing or other sources of
moisture--such as clothes hung to dry on basement lines--increase
humidity in the air, causing condensation.
Solution: Repair plumbing
promptly, open windows or dry clothes in an automatic dryer vented
outdoors. If the problem persists, experiment with using a
large-capacity dehumidifier to eliminate condensation. Try borrowing
one from a friend or neighbor before investing in what may turn out to
be the wrong remedy.
Concentrate On The Source Of Persistent Problems
If every apparent, logical way of eliminating wetness fails to produce
a dry basement, do not waste time or money on random potential
solutions. Finding the cause of the problem is absolutely essential to
its cure. The hardest type of water problem to correct is one created
by faulty construction practices at the time the house was built.
Proper drainage is a crucial consideration in selecting the site for a
new house. This includes not only the drainage of surface water but
also drainage of any subsurface or ground water that may already be
present, or that may accumulate over a period of time and be blocked
from its normal course of flow by the new construction.
If the subsurface or ground water level is close to the underside of
the basement floor slab, water rises through the slab by capillary
action, producing dampness. If the subsurface or ground water level is
higher than the basement floor, water leaks in through the walls and
floor or enters by capillary action, causing standing water in the
basement and, at times, dampness in the rooms above. Under ideal
conditions, a house should be situated so that even during rainy
seasons the subsurface or ground water level is at least ten feet below
the finished grade--well below the average basement floor.
In some cases, it is impossible to completely eliminate dampness from a
basement whose construction did not take into consideration the basic
principles of good drainage. Only after soil borings have been done can
anyone knowledgeably predict which, if any, course of action has a
chance for success.
Weigh Alternative Methods Of Treatment
An accurate diagnosis of the main cause of persistent basement wetness
may lead to a recommendation of one or more of the following actions:
- Redirect Water Away From Foundation
The various exterior waterproofing barriers have varying levels
of effectiveness in protecting the outside wall areas. But wall
anti-leaking barriers do not affect water penetration due to water
accumulation at the footer or floor level. The ideal solution to this
problem lies in directing the accumulation of water away from the
foundation or into drainage or pumping system.
- Install An Interior Drainage System
To control leakage in the basement, you may install a drainage
system on the inner side of the foundation. The floor is broken up
along the perimeter of the basement wall and drain tile is placed in a
trench that carries the water to a discharge point, or sump pump, which
takes the water away from the house. With hollow block walls, holes may
be drilled at the bottom to allow the water to pass into the drain pipe
and relieve the water pressure. The trench may then be filled with
gravel and the floor replaced or recemented. If installed correctly
this system will remove basement leakage water. Channels may also be
installed on the basement floor to take the water away through a sump
pump.
- Apply Waterproofing Compounds To Interior Walls
Only in cases where mild and occasional capillary seepage
occurs are applications of waterproofing paint or other interior
compounds likely to provide any lasting degree of improvement in
achieving a dry basement.
Capillary waterproofing materials can be applied to either
exterior or interior wall and floor surfaces. If properly applied, they
will penetrate several inches into concrete and close off capillaries
or minor cracks by forming crystals in the presence of water.
Do-it-yourselfers should carefully read the label to determine the
waterproofing product's limitations and terms of any guarantee
promised.
Waterproofing paint is most effective if applied directly over cement; not existing painted walls.
- Injection of Waterproofing Substances
Into
Exterior This type of treatment does not require excavation. Instead,
sodium bentonite or another substance--sold under a variety of trade
names--is injected into the space between the soil mass and the
basement wall. It swells to many times its dry volume when it is first
put into slurry form. The slurry will tend to penetrate and plug cracks
where water might also find a path to the basement interior, thus
reducing the flow of water.
The type of soil and the skill of the person directing or
performing the injection operation has a strong bearing on the success
of this method to correct basement wetness.
Certain chemicals, such as salt, will tend to prevent the
effectiveness of the sodium bentonite, and undetected underground
barriers (such as rock or wood) can seriously impair the effective use
of this method.
In very pervious, coarse sand to gravel soils, the soil
itself can be injected with bentonite slurry, but it may not be
possible to inject bentonite slurry into clay soils, silt soils or
sandy soils where the sand is of fine to medium gradation.
The injection of sodium bentonite slurry beneath a basement
floor might result under certain circumstances in the floor being
raised by hydrostatic pressure, and tend to plug any drain tile that
might exist under the floor.
Under Title I, Property Improvement Loan Program, the U.S.
Department of Housing and Urban Development (HUD) "does not permit
loans to be made for waterproofing of a structure by pumping or
injection of any substance in the earth adjacent to, or beneath the
foundation, or basement floor."
- Excavate
Sometimes it is necessary to resort to the extreme measure
of exposing the basement walls, treating them to make them watertight,
and then regrading the soil. Among possible treatments are:
Covering the walls with a prepared waterproofing felt or
fabric coated and cemented together with hot coal-tar pitch. If
properly applied, the membrane is a very effective method of
waterproofing. However, it is very expensive, and if subsequent leaks
develop they may be difficult to locate and repair. Remember, water can
still come in through the basement floor.
Applying two coats of portland cement mortar to the surface
of exterior walls. Called parging, this work should be done only in
dry, mild weather. Fall is the best time, because the subsurface water
level is usually low and temperatures are more favorable for making
watertight concrete.
The newly cemented walls should be properly protected and
cured. Freezing or rapid drying of the concrete by sun or wind can
damage it and make it worthless. In very wet soils, the parged wall
surfaces may be given two coats of hot coal-tar pitch.
Keep in mind that settlement and thermal expansion and
contraction of the wall can affect the parging; preventing it from
bridging cracks that develop in the walls.
Applying polyethylene or polyvinyl film, a vapor barrier
material, to the exterior surface of the walls. Manufacturers'
instructions should be followed in applying the material.
Installing drain tile around the footings, at least on the
sides where trouble is occurring. This procedure is generally
recommended in addition to one or more methods above.
Good, four-inch drain tile should be used, laid parallel
with, and at the bottom of the footings. Great care must be taken to
see that the bottom of the tile is not lower than the bottom of the
footings, so that the footings are not undermined.
In normal, porous soil, the tile should be covered with 18
inches of screened gravel. In heavy, non-porous soil, the gravel should
extend almost to the top of the excavation.
This footing drain and belt of gravel should drain off all
seepage water and prevent the accumulation of water around the walls.
This method is especially suitable on the upper side of a house located
on a hillside.
Choose A Waterproofing Contractor Carefully
A properly applied waterproof barrier may prevent the water form
seeping through the wall, but allow it to seep deeper into the ground
until it finally comes through around the footer or basement floor.
Thus, it is critical that a knowledgeable and competent contractor
evaluate the problem.
Deal with a waterproofing company that has a good reputation in the
community--one that has been in business in the same area for several
years, and depends on the satisfaction of its customers. Find out if
the company is bonded, licensed and certified (where applicable). Also,
find out if the company trains its workforce through apprenticeships or
other training programs.
Beware of salespersons or contractors who ask for large payments in
advance. Reliable contractors generally do not require more than a
minimal downpayment.
Obtain written estimates from at least three contractors. Compare the
cost of the work to be done, the quality of materials to be used, and
the cost of financing the work. Insist that each estimate include the
cost of materials and labor and a statement of exactly what the
contractor will do and how long the work will take.
Check each contractor's reliability with the local Better Business
Bureau, previous customers, and friends who have dealt with the same
problem.
Tips To Remember
- After
selecting a contractor to do the work, ask for a written contract in
accordance with the estimate. Read this contract carefully before you
sign it. Make sure you understand its contents. If you have a question,
ask an attorney to review the contract for you. The contract should
include the following:
- The contractor's name, address, telephone number.
- A full description of the work to be done and a list of the materials to be used.
- A definite date on which work will start and the length of time for completion.
- A provision that no change in plans or specifications may be made without the homeowner's written approval.
- A requirement that the contractor will obtain any necessary
permits or licenses to assure the homeowner that building codes will
not be violated.
- Details of payment -- the down payment, monthly payments,
number of payments, the total finance costs, and annual percentage
rate. The annual percentage rate is your key to comparing costs for the
lowest rate.
- A statement that the contractor is responsible for insuring his employees against possible injury on the job.
- A warranty or guarantee with all conditions spelled out. For
example, if what the contractor provides doesn't solve the water
problem, what is the company obligated to do and what are the
alternatives?
- The contractor's signature and local or state licensing number, if licensing is required.
- If
you plan to finance the work and the contract terms could give the
contractor a lien, mortgage on other security interest on your home, or
if you are solicited by a door-to-door salesperson, make sure the
contract contains a provision allowing you to cancel within three
business days after signing it without penalty.
- When
signing the contract, make sure that all blanks are filled in, and that
it contains everything the contractor promised. Do not rely on oral
guarantees.
- Make sure you have a copy of the written contract, signed by both parties, should you have trouble with the contractor later.
- If
and when the contractor requests your signature on a completion
certificate, inspect the job carefully to see that the work has been
done satisfactorily, before signing.
- Even if the job
is finished, do not sign the completion certificate if you have a valid
complaint about the work. It is not unreasonable, for basement
waterproofing work, to delay signing until after heavy rains have come,
or a specified period of time has elapsed.
