Drainage

Standing water inside and/or seepage into residential crawl spaces and basements can cause frustrating problems for the homeowner. These problems can be both immediate and long term. For example, standing water and mud inside crawl spaces make it very difficult and messy to gain access under the house for inspecting, maintaining, and servicing electrical circuits, drains and water lines, heating and air conditioning, and other utilities. Wet basements and crawl spaces are sources of high humidity, which can produce surface condensation, mildew and fungi, musty odors, and an unhealthful environment. Such moisture can cause deterioration of floor joists, beams, subflooring, 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 wall settlement and cracking. Serious seepage under the foundation footer may erode soil away and cause the wall to drop or crack. Excessive moisture can eventually penetrate the subflooring and buckle the flooring or cause warping, making doors and cabinets difficult to close or open. 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 underflooring insulation collects moisture, or sags from excessive wetness, 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 cause of the problem. Some homeowners 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 investment. Homeowners, in such situations, they should immediately seek professional assistance in assessing the source and extent of the problem and in finding a remedy.
Some problems may be solved simply by repairing an obvious gutter or downspout leak, while other problems may have causes which are difficult to identify and very expensive to fix. Severe crawl space and basement water problems may cost several thousand dollars to remedy. Always use a competent professional to help you find and eliminate the source of your problem. Don’t settle on quick and cheap fixes which merely deal with the symptoms of the problems.
In order to prevent wet crawl spaces and basements, it is important to understand where the water is coming from. There are four common sources of water that seeps into basements:
Surface water running down foundation walls
Groundwater in water-saturated soils being pushed into the basement by hydrostatic pressure
Storm sewer water from the municipal storm sewer system backing up into the home's existing perimeter foundation drain and leaking into the basement (this can only occur if the perimeter foundation drain system is connected to the municipal sewer system)
Sanitary sewer water from a combined municipal storm/sanitary sewer system backing up into the home's drain system, causing sewer water to come up through sink drains and floor drains on lower levels.
When homeowners experience wet basements for the first time, it is imperative to determine if the water problems are going to reoccur or if it was a one-time event. Essential to solving this question is determining from where is the water coming.
The good news about these unplanned indoor pools is this: while wet basements are often thought of as one life’s biggest home repair headaches, they are generally easy and inexpensive to fix. Most people blame a wet basement on a high water table, the natural level of water in the soil under the building site. This is another myth that could not be further from the truth. Homes are not built below water tables. Builders attempting such a feat would find themselves constructing a foundation in a muddy mess. Likewise, basements that flood after a storm are also never caused by rising water tables. A water table moves slowly and seasonally. If your leaks show up after a heavy rainfall or snowmelt, the cause of your problem is far easier to spot and to fix.
Most basement leaks can be traced to trouble with the drainage conditions around the outside of the house which result in surface water running down foundation walls or saturating the areas around the foundation and entering the footing tiles. If too much water is allowed to collect in the soil around the foundation, it will naturally leak into the basement through the walls, or even up through the center of the floor or overwhelm a sump pump.
The solution lies in improving these drainage conditions. Something that is easy, cheap and highly effective. Here’s where to begin:
Surface Water
Good Gutters
Roof drainage is, by far, the number one cause of basement leakage. Since roof surfaces are as large as the house, they collect lots of water in heavy rainstorms. What happens to that collected water can make the difference between a wet and a dry basement.
Properly designed gutters should have at least one downspout for every six hundred (600) – eight hundred (800) square feet of roof surface. Gutters must be clean. Dirty gutters fill up and the water overflows directly where you don't want it to be: near the foundation. It’s also important to make sure the ends of the downspouts are extended to discharge at least four (4) to ten (10) feet from the foundation. Spouts which discharge too close to the foundation are like big fire hoses that just blast water into the basement.
Be careful not to discharge downspouts too close to your neighbor's property. Most towns and cities have ordinances that prevent downspouts from discharging too close to the property line and causing water problems for neighbors. The local building inspections department can provide you with the minimum distance.
Sloping Soil
Next to gutter problems, the angle of the soil around the foundation perimeter can also cause wet basement woes. The soil should slope away from the house to keep rainfall from collecting against foundation walls.
The angle and type of soil are also important. The soil should slope downward 6 inches over the first four (4) feet from the foundation wall. Thereafter, it can be graded more gradually but should never allow water to run back towards the house.
If grading needs improvement, use clean fill dirt (not top soil) to build up the soil around your house. Tamp the soil down to the correct slope and finish with a layer of top soil and grass seed to prevent erosion. Or, just use stone or mulch. Whatever the top layer is, be certain the slope is established with the fill dirt - or else the water will just run through the more porous material and into the basement. Also, don’t use straight top soil for the grading improvement. This kind of soil is too organic and will hold water against the foundation, which is the opposite of what needs to be done.
It is also important to avoid landscape treatments that hold soil to the house. A brick, stone or landscape timber edging around flower beds adjacent to foundation walls may look attractive, but these edges can prevent water from draining away from the foundation and increase your risk of flooding.
Any hills sloping down toward the house may be the source of the water at the foundation. If this is the case, a civil engineer may be required to analyze the situation and determine the appropriate solutions. In most cases where the yard area slopes toward the house and surface water collects or ponds near the foundation wall, a V-ditch or swale should be constructed around the house to allow surface drainage from both the foundation wall and the other yard areas to an adequate ditch or storm drain. Such cases often exist where the front street is higher than the first floor of the house or when the house is built on the side of a hill.
One of the single largest problems is homeowners who sign the purhase contract argeeing to take responsibility for the final grading of a site. The owner is now responsible for understanding and properly grading the lot. The second owner buys the site with the full opportunity to understand the problems of the property by using a home inspector and an attorney.
A building permit is not issued until the building pad is to rough grade, the actual elevation of the first floor is not regulated and the builder or home owner actual is the ultimate determiner of the building elevation. There are many varied house construction styles and methods and the city does not regulate which ones must be used unless it is required in a lot covenant or noted on the plat as a restriction. Any attempt to blame the city for this problem is misplaced.
Sloping Pavement
Paved areas next to the house that slope toward the house can be the source of the problem. Sometimes paving settles over time and water flow can change direction toward the house. If this is the case, the paving should be removed and replaced so it slopes away from the home.
Controlling Subsurface Groundwater
If no surface water sources are found, then the source of the water is likely subsurface groundwater under hydrostatic pressure. Unfortunately, subsurface groundwater problems are more difficult and more expensive to fix than surface groundwater problems.
When the groundwater levels outside the basement rises above the level of the floor, the basement acts like a boat in a pond. If a boat is sitting in water, water will leak in through any open cracks or holes. It works the same way with a basement. Hydrostatic pressure can push water through hairline cracks.
Symptoms of this are water coming up through cracks in the basement concrete floor or water coming in at multiple locations.
If you have an older house and the house has a basement with no sump pump, it is likely the perimeter foundation drain system connects directly into the city storm sewer system. If the level of the basement is below the street level, there is the potential of storm water backing up in the city storm sewer system and being pushed into the perimeter foundation drain system. This can saturate the soils around the house at the basement level with storm water under hydrostatic pressure, causing water to leak in.
Another source of subsurface groundwater is an underground spring.
No matter where it is coming from, the best way to control subsurface groundwater is to install some type of perimeter drain system to relieve hydrostatic pressure. The groundwater is pushed into the drain system and not into areas where it can damage carpets, walls or belongings. The water drains by gravity into a sump pit where a sump pump discharges it out of the house.
There are two basic types of drain systems for wet basements. One is a perimeter above-slab gutter system installed at the base of the exterior foundation walls on top of the floor slab. It doubles as a base material for the wall. The other type of drainage system is a below slab perimeter drainage system. The below slab system requires the partial removal of the concrete floor slab and installation of drainage pipe making it more expensive than the base gutter system.
It is believed that an under-floor drainage system is better because the under-floor drains are believed to relieve the hydrostatic pressure before the water reaches the bottom of the floor slab.
There are many springs in the Lake Mills area, but predicting their location and preventing construction on those sites would be an expensive and highly unreliable process.
Storm water backing up into your home
In many older houses with basements (mostly pre-1980), there is a perimeter foundation drain outside the exterior wall, at the level of the basement floor, next to the footings at the time the house was built. A pipe was usually installed from the perimeter foundation drain to the street where it was connected to the city storm sewer system.
This can become a problem as the city storm sewer system becomes too small when more development causes more rain runoff. When this happens, the rainwater in the sewer system can get so high that water flows backwards toward the house. The perimeter foundation drain fills with water and releases large quantities into the soil next to the footing and basement floor. The soil becomes water-logged and the water which is under hydrostatic pressure leaks into the basement.
Usually the installation of an interior perimeter basement drain system connected to a sump pump will take care of the problem. The interior perimeter basement drain system can usually pump the water out and onto the ground as fast as the water is backing up from the city storm sewer system.
If that doesn't take care of it, the other, more expensive alternative would be to dig up and cap the pipe that is running from the house to the street from the perimeter foundation drain. However, this is not always possible because many times, this pipe is also draining sanitary waste from toilets and sinks in the house.
If you believe you have this problem, contact an experienced contractor for advice.
Sanitary sewer water backing up into your home
If the water is coming up through floor drains or sink drains in the basement, then the problem is likely water backing up from the municipal sanitary sewer system. The Lake Mills Wastewater Utility has sanitary sewers designed to transfer sanitary waste only. When stormwater is introduced to the sanitary system, either through inflow or infiltration, overflows can result.
Homeowners commonly use sump pumps in their basements to battle moisture and flooding issues. However, water from sump pumps should NOT be discharged into the sanitary sewer system. That’s called a cross connection, and it results in higher sanitary sewer costs. Often, this is a hose leading from the sump to a laundry tub or a floor drain. As you may know, water that goes down any drain in your house leads to the sanitary sewer system and eventually ends up at a wastewater treatment plant, where it is treated before being released back into the environment. Sump pump water is what engineers call "clear water"-most often rain water, ground water, or snow melt. This water should flow directly into area streams, ponds, and lakes. Water from sinks, showers, tubs, toilets, and washing machines is wastewater and must be treated before it is discharged into the environment. As the groundwater rises in an area, water pumped out of the basement and onto the yard generally finds its way back into the basement. This frustrating cycle leads many to redirect the sump pump to the sanitary sewer system.
You can imagine the mess this creates for homeowners because it usually means they are getting other people's fecal waste backing up into their basement. Homeowner can install backflow preventers that help stop sewer water from flowing backward into the house.
Unfortunately, because the city sanitary system works in conjunction with every house sanitary piping, the backflow preventer usually cannot be located on the house's main sewer line. It usually requires several backflow preventers at all basement drain locations, such at every floor drain, sink and toilet.