A house was built on a slab; when it rained water soaked through the walls into the closet.
A hillside property owner found water running under the front of the house and coming out downstairs.
Another hillside house had a long driveway going down to the house; water ran down the driveway right into the house.
A house was built over an old spring which had been dormant for years. Then it became active.
Neighbors up the street put in a pool; now a drainage problem exists which was not present before.
Southern California is an area of very little rainfall; but it does rain. Because of the generally arid climate many homes have been built with little or no consideration for drainage problems. We treat some of the conditions that foster mold and mildew. We are not mold
and mildew experts. We do not identify or evaluate mold or mildew, nor do we
treat mold and mildew. For more information about problems associated with mold,
identification of mold, and treatment of mold please refer to the following
website: http://www.cal-iaq.org/MIMH_2006-06.htm"
Some helpful links may also be found here: http://www.cal-iaq.org/iaqsheet.htm
Our primary service area extends from the Los Angeles International Airport
up the coast to Camarillo, then east to Studio City, south along the 110 to
Century Blvd, and west back to the airport. This includes the following zip
codes: Santa Monica (90402, 90403, 90404, 90405), Culver City
(90320, 90232), Marina Del Rey (90292), Venice
(90291), Playa Del Rey (90293), Westchester
(90045), Ladera Heights (90056), Beverly Hills (90210,
90211, 90212), West Los Angeles (90025, 90034, 90035, 90064), Mar
Vista (90066), Brentwood/Bel Air (90049, 90077), West Hollywood/Hollywood
Hills (90048, 90069, 90046, 90068), Hancock Park and surrounding
areas (90004, 90005, 90010, 90019, 90020, 90036, 90038), Pacific
Palisades (90272), Malibu (90265), Topanga
(90290), Tarzana (91356), Woodland Hills (91364), Encino
(91315, 91436), Calabasas (91403), Sherman Oaks
(91403, 91423), Studio City (91604), Agoura/Agoura Hills (91301),
Westlake Village (91361), Thousand Oaks/Newbury Park (91320, 91360,
91361), Camarillo (90310, 90312) Sometimes we are asked to go outside of our primary
service area to consult on property drainage issues. We are often able to
accommodate such requests. The consultation fee will be higher for these areas,
but still applicable to the cost of major drainage work. If you wish to find out
if we'll go to your area, please call us. Here are some examples of other areas
we've gone to: Rancho Palos Verdes (90275), Rolling Hills (90274),
Torrance (90501, 90503), Manhattan Beach (90266), La Cañada Flintridge (91011),
Pasadena (91105, 91106), Glendale (91206), Mount Washington (90065), Simi Valley
(93063, 93065) Resources on the Web Hammer Company, Inc.
Problems
Soggy carpets, buckled floors, damp basements, flooded yards, mold and mildew
allergies; frazzled nerves accompany rain storms for many property owners. Over the years we have observed the following kinds of incidents:A homeowner was out of town for the holidays. When he came home it was raining, the furnace was out, and there was a foot of water in the basement.
Although the Los Angeles area is in a semi-arid region, there have always been springs and streams, especially in the canyons and hills. The early native residents depended upon the natural springs and streams for their water supply. These springs and streams dry up in the summer and during prolonged drought they almost disappear. Few are active year around. Most of these water flows disappeared during construction booms because of the desirability of the surrounding property. Much of that water is now running down storm drain systems. During grading operations – establishing building pads, roads, etc. – underground courses have been disrupted and redirected, perhaps unknowingly, when construction occurred during a dry spell. A grading operation may have exposed strata that will conduct water. That strata may emerge on some other property, and then so will the water.
The best time to solve drainage problems is before or during construction. But drainage problems can be alleviated or eliminated after construction. The first step is to find possible sources of the water. A roof collects a lot of water and is the source of many basement water problems. The yard grading or the neighbor's yard might be the source, or the whole neighborhood.
Next the water has to be collected. This starts with roof gutters and down-spouts. Water should not be allowed to come off anywhere it wants to. It should be brought down to where it can be handled. Gutters need to be inspected and cleaned periodically; they have a way of being plugged up when they're needed the most. Catch-basins located at low, swampy spots are good collectors. Paved gutters are sometimes helpful, but only for surface water. The trickiest collection problem is sub-surface water. This can be collected by means of a "French" drain, weep drain, or subterranean
drain; a drain that intercepts the water below the ground.
Finally, the water collected must be conducted away to a safe point of discharge. This usually requires underground piping, and occasionally sump pits and pumps to remove the water.
Intuitive solutions are often unproductive. Many people build a sidewalk next
to the house or a little concrete curb; but such devices will not stop water that is going under a house. It helps to appreciate the volume of water to be handled. A storm that drops one inch of rain on a typical fifty by one hundred fifty foot lot has deposited
over 4000 gallons of water. For most homes that is more than the water that could be used by turning on every water outlet on the property and leaving it run for three hours, or about half of the water from a typical residential swimming pool. All of that water goes somewhere. It can go over, under, around or through obstacles. Building walls, waterproofing interiors, digging trenches, or just gritting one's teeth storm after storm are poor solutions.
Solutions
Roof and surface drains
Treatment for water intrusion often begins with guttering the roof of the house. Water that falls next to the house and seeps into the ground forms a bubble of moisture under the house. When it passes under a concrete curb or footing it rises to the same level on both sides. Gutters need to be large enough and positioned so as to intercept and carry off the water from the roof. If the gutter water is then discharged next to the house it often only makes the problem worse by concentrating large amounts in one location. Down-spouts from gutters need to be connected to a drainage system that conducts
this water away from the house.
Similarly, yard-water that puddles around the house can also make its way back under the house.
The Uniform Building Code sets standards for yard grading to prevent seepage
back under the house. The standard is for the exterior grade to be a minimum of
6 inches below the top of the footing, and to slope away from the house at a
minimum of 2% (1/4 inch per foot) to an approved drainage device (See diagram: Surface
Drainage Standards ) Catch-basins (a box with a grate on top set at ground level and connected to drain pipes) can be installed in low spots around the house to carry off water. These typically have openings 8 inches square or larger. The typical drain inlets installed decks and lawns that are 3 or 4 inches in diameter are often ineffective. Two or three leaves washed over them can severely restrict or eliminate their
functionality.
Once the water is collected it needs to be discharged safely. This usually means in the street gutter, but may
also mean a nearby gully or canyon. Care must be taken not to create a hazard by the discharge of collected water.
French (subterranean, foundation) drains
Water that is migrating under the surface is best intercepted and controlled by use of a
French drain. People refer to many schemes as French drains. When we use the term French drain we mean a trench, preferably with the bottom below the level of the sub-floor, or better yet below the bottom of the house
footings, and:
Sometimes the trench is wrapped with filter fabric to reduce root invasion, though that has the disadvantage that it tends to fill up with silt which can stop the drain from functioning.
These French drains typically run all the way across one or two sides of a house, and occasionally three or four sides. The critical consideration is depth. Almost any water intrusion problem can be solved with a deep enough French drain. However, a French drain is expensive to construct, and the deeper it is the costs go up more than proportionately. We have adopted the guideline of preferring to start the drain at an elevation 6 inches below the bottom of the foundation footing whenever practical. This is not always practical due to structural considerations,
cost, or outlet requirements.
French drains are susceptible to silt intrusion and root invasion, since they are not sealed. Tall shrubs and trees should not be near the drain when possible to prolong drain life. Shallow drains (12 to 18 inches) have been known to clog up within 2 years when installed next to ivy. Other drains have been in service for fifteen or twenty years and appear to be functioning well.
Sump pits and pumps
It is always preferable to conduct water by gravity to a point of safe discharge. Sometimes that is not practical, and sometimes
it is not possible. In these cases, a sump pit and pump is required. A sump pit is any device or structure that serves as an underground pit or container to receive water. The pit needs to extend a foot or 18 inches below the drain inlet to allow for pumping operations. The pump is automatically actuated any time the water level is
high enough to activate a float switch. It is then pumped to the street or other suitable drainage course.
We try to avoid using pumps whenever possible. Power failures, pump failures, and clogging can easily defeat the operation of a drain system just when it is needed most. When we do use pumps they are usually sewage pumps which are designed to handle water more aggressively than regular sump pumps.
Drainage Estimates and Consultations
Drainage problems typically require some diagnosis and evaluation in order to propose treatments. Such proposals usually include costs for work we offer to perform. We charge a nominal
fee for this service. This fee is applicable against any major drainage work we do as a result of our proposal. Drainage treatments are never guaranteed to solve the problem. Water intrusion is too elusive to give guarantees on results. If there have been geological reports, soil engineer reports, home inspector reports, termite reports, owner's observations, etc., it is helpful to have copies available at the site at the time of our examination. Such reports usually preclude the necessity to crawl the house if it is on a raised foundation. If it is necessary to crawl the house there is an additional charge. It is preferable for the owner, or in the case of a house in escrow the buyer, to be present at the time of the evaluation. Elusive water problems can usually be described and evaluated more effectively person-to-person on the site than in written reports or proposals.
1645 Euclid St., Santa Monica, CA 90404
(800) 660-1452 (310) 450-1122
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