Most water problems that homeowners encounter can usually be by controlling water above ground. Simple but effective means of controlling those above-ground problems may prevent structural damage to your home as well as dry up those basement damp areas. Most home owners are un-aware that saturated soil increases the soil pressure on the basement wall which can the lead to cracks, shifts, collapses and other structural problems. Start first by looking to the roof,. An inch of water on 1,000 square feet of roof amounts to about 623 gallons of water. A foot of compacted snow on that same roof could contain up to 4 inches of water, or nearly 2,500 gallons. Getting all that water away from the house is a big first step to preventing basement problems and can prevent needless costs in repairs. Ensuring your eaves trough have extension or splash pads that adequately remove water from around your house is the first step in preventing water intrusion or damage to your home. A slope of about 1 inch per foot drainage near the foundation wall is usually adequate. Also, the ground should be sloped to carry the water away from the downspout discharge.
In addition to proper drainage above ground, a properly installed drainage system below ground is important to keeping your basement dry. A properly installed drainage system at the house foundation will prevent many water problems from entering your basement and eliminate saturated soil conditions next to the wall. A study of leakage problems showed that more than 90 percent were due to improperly installed drainage systems. The engineer says a properly installed foundation drainage system includes drainpipes placed alongside the footing. In areas with high water tables, a drainage system can also be installed around the inside of the footing and under the basement floor. Using granular material to allow the movement of water and filtering material to keep soil from plugging drain pipes is essential to keeping the system functioning for the life of the house. Granular backfill should be used next to basement walls, he notes. Using soils that don’t drain well can cause pressure on the walls if the soils become saturated. Most contractors now use a dimpled wrap installed against the foundation ensuring water drains down to weeping tile thus preventing hydraulic pressure from building against foundation walls. Poor drainage will also increase the potential for moisture or water vapor to move through the wall into the basement.
In certain areas, that moisture can carry minerals that are detrimental to the concrete. Basement walls that have had water or moisture leaks will usually leave an effervescent stain which is typically non-removable. Homeowners and home inspectors always view effervescence as indication of water penetration.
Window wells also need to be correctly constructed with drains linked to the foundation drains. Soil elevation in the window well should be several inches below bottom of window and sloped to the drain. The cost of installing the drainage system during new construction is minimal and is minimum building code requirement.
Window drains are usually installed in two ways; one is to place window well drain on top of foundation weeping tile and then fill with clean stone, thereby preventing entry and possible blockage from debris; two is to connect window well drain with Tee into foundation weeping tile and close off top of window drain with mesh sock or other means of preventing debris entry. As a home inspector I find many window well drains that are open and partially filled with leaves and toys etc. A blocked window well drain will allow build-up of water in heavy rain or snow melt and could enter basement windows.
Many homes have in-ground drains for roof drainage discharge. These usually work well in warm months but in winter they are prone to freezing. I always recommend to my clients that they install a Tee at the top of ground drain which will serve as run off if ground drain is frozen but water is melting on roof. As the ground is the last are to un-thaw water will back up downspout and then freeze at night, installing a Tee will prevent this.