DAMP, MOIST, WET ? Damp, moist, wet or overly humid basements are like the common cold. Any body can get one and they usually come with wet weather. Unlike the common cold, this is predictable and avoidable. Like many things in nature, its tenets are simple, obvious, and undeviating.

RAIN CAUSES DAMP BASEMENTS. All water comes from the sky. It is rain that dampens the earth, feeds creeks, streams, rivers, the underground water table, and eventually, the ocean. But, water doesn't like to flow through solid objects (like dirt), so it stays largely on the surface. Water would rather travel miles to the ocean than a few feet through solid or even semi-solid ground.

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Damp basements result from conditions that allow water to get into the foundation back-fill.

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SO WHY IS IT OOZING IN MY BASEMENT? When water does get into the ground, it continues to flow downward and away, unless something slows it. Even when it slows down or stops, water is so energetic and so determined to keep moving, that it will change form and escape another way. Damp basements result from conditions that allow water to travel downward into the foundation area and then gather or stop there. Secondary effects occur as a result of the water being there, and what it does to try to leave.
WHY DOES THIS HAPPEN? When a building is constructed, with a basement, the first thing done is to dig a big hole, called an excavation, to contain the foundation. Once the foundation footing(a strip of concrete approximately one foot deep and two feet wide) is laid and the foundation wall (usually of concrete block) is up, there remains an area between the foundation and the un-dug, or undisturbed soil, about two to three feet wide. This area is then refilled, or back-filled, with soil left over from the construction site. This back-fill material is loose and porous and will never be of the same nature as the original soil which was packed down by nature over thousands of years. This loose, air filled, "disturbed soil", will let water pass through it readily (as compared to undisturbed soil). The only saving grace is that water will not easily pass through dirt, especially if it is sloped so that the water keeps moving. Wherever there are flat areas or areas where the soil is sloped toward the building, any water that falls on or flows toward the foundation area (the ground around the building up to three feet from the foundation wall), will soak into the foundation back-fill area. Depressions in the soil around the building, which often occur from normal settling, also encourage this. The soil beyond the back-fill, called "undisturbed soil", is packed down by nature over a long period of time; where it is high in clay content it is almost totally impervious to water penetration. Thus, any water that makes its way to this area ultimately gets trapped (in the back-fill soil) between the" undisturbed soil" and the foundation. Continual additional inputs of new water can keep this area saturated; since the water must leave by either evaporation or capillary action, both of which are slow processes.
THEN WHAT HAPPENS? Constantly saturated soil next to the foundation structure ultimately results in secondary effects. Some of these effects are: damp walls, as the moisture migrates through the concrete; wet walls as water runs between cracks in the joints and fills hollow areas; mineralization or efflorescence, caused by long term dampness as moisture migrating through the wall evaporates, leaving minerals behind; appearance of water at the floor level, as the saturated soil drains itself of excess water, through the joint between the wall and floor, or some other opening. The presence of water in any form against the outside of the foundation means water pressure in various forms, and will always result in the intrusion of water and/or moisture into the interior. Secondary effects can be more serious including cracked or bulged walls, settled foundations and sunken or buckled floors.

Water and moisture buildup in the back-fill soil around the foundation has several negative effects. Two of the most severe affect the footing and the foundation wall. Thefooting is affected by water gathering at the bottom of the original foundation excavation (the bottom of the back- fill). When this area stays moist or wet for a long period of time, or when it gets extremely wet for short periods, the soil becomes plastic (or soft, mucky)and the heavy weight of the building pushes downward (sinks) slightly. When this happens, it almost always does so unevenly and the result is cracks in the foundation. The cracks are either shear cracks (vertical cracks) or step cracks (follow the mortar joint in block and brick). When the back-fill becomes thoroughly saturated with water, it also becomes heavy and plastic (plastic means pliable), exerting greater pressure on the foundation sidewall. During extremely cold weather, when this saturated soil freezes (and expands), tremendous pressures develop against the wall. When the wall can no longer resist these pressures it moves slightly inward, bulging, and splitting horizontally on the interior side. This weakens the wall and simultaneously reduces its waterproofing qualities. When the soil warms and thaws, the soil shrinks and settles downward occupying the new volume of space available to it which has been provided by the moving inward of the wall. This in turn provides an even lower area on the ground surface, at the same location,which in turn invites more water to gather and enter the soil; accentuating and promoting further deterioration.

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Make sure that any surface water traveling across the lot is directed away from the building.

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WHAT CAN BE DONE ABOUT IT? Make sure that any surface water traveling across the yard is directed away from the building. Keep the gutters clean and in good working order; do the same for the downspouts and downspout drains. Provide a soil curb at the exterior of the foundation by building up the soil, preferably of clay soil or clay bearing soil (the more clay, the better for sealing purposes --top soil is spread on the finished surface only), at the foundation wall so that it is six to eight inches higher at the wall than it is two to three feet away, thus making it necessary for water to flow away from the foundation soil curb all the way around the foundation, any water falling onto the back-fill area, or flowing across the ground towards the foundation, will find it difficult to make it into the foundation back-fill.
The back-fill soil around the building will give up its moisture slowly. The drying out process may take several months. Patience is needed, the ground will dry out once the necessary drainage corrections are made.

Proper ventilation will facilitate and maintain the drying out process. Windows should be opened and perhaps a fan installed to force air through the basement or other damp areas. Simply placing a common room fan on the floor to circulate air is an improvement. A dehumidifier may also help, but it's use should only be temporary or occasional. All basement areas should maintain good ventilation.

SOME COMMON BUT IMPROPER APPROACHES: This problem is so pervasive, that a myriad of approaches have been invented to attack it, most of them ineffective or even destructive. A common approach is the use of "French Drains". French Drains should not be used next to the foundation as they invite water into the ground. Sometimes French Drains are useful at the base of a hill or as area drains when at least seven feet away from the building. French Drains should not be confused with foundation perimeter drains (or footer drains), which are normal in many homes.
Footer drains, found at the exterior base of the foundation wall are safety drains drawing away water only when all else fails. When a footer drains becomes a working drain, it eventually clogs up and becomes useless, eliminating it's safety protection.
There is absolutely no product or procedure that can be used on the interior of a foundation wall to dry it up; they just don't work. Of course, so-called "Waterproofing Company" practices should also be avoided. The information we give you here is, remarkably, not common knowledge; therefore, when hiring a workman to make corrections, do not rely on his expertise; you must take charge and make yourinstructions very clear.
THE COMPARATIVE COST: Generally speaking, filling in soil around the foundation is somewhat less expensive than all other approaches, but tends to be a more permanent solution. Especially since the work can often be done by the owner on a few weekends.

NOTE: The preceding information is applicable to about 98% of all damp basements (including commercial buildings), especially in areas where the soil is high in clay content and, for the sake of clarity, is simplistic in its description; there are rare situations where water, causing damp basements, is from another source. Sandy soils can be treated similarly, especially if there is some clay available in the area to mix with and enrichen the characteristics of the soil at the surface immediately around your building.

When you need to be sure, call us. We do consulting-at-a-distance, and can solve many problems over the phone. Locality is not a barrier to at-a-distance consulting which can be done for virtually any place in the USA, and often other areas as well.