Why do basements leak?
Over a long time, every basement will eventually leak. Let’s take a look at some of the most common reasons.
Exterior drain tile will eventually become clogged with sediment and dirt. Even if the pipe is clear, the small holes or slits that allow water to enter the pipe will clog. This allows a water table to rise around the house creating hydrostatic pressure. Once the water is at a level above your basement’s lowest point, hydrostatic pressure is constantly applied to your foundation walls and floor. The water will find the path of least resistance in order to find its level.
The cove joint (where the footer, wall, and floor meet) is the most common area to leak because this is the weakest point in the foundation.
The fill dirt around your house is less dense than the original soils that have not been disturbed. Settlement of the fill dirt can continue for 7 to 10 years, and combined with seasonal expansion and contraction, it will put much pressure on your foundation walls. Water that flows and settles around your house in the fill dirt decomposes the lime in your concrete or concrete block and mortar joints. Concrete and concrete blocks are made of sand, stone and lime (lime is the bonding agent in the formula). Exterior waterproofing treatments deteriorate over time as they are subjected to hydrostatic pressure and freeze/thaw cycles. Once this occurs, the water starts seeping through the porous concrete walls creating leaks and possible structural damage.
Six Components to a Complete Waterproofing System
Moisture barriers are non-porous products applied to the interior of the foundation. All moisture and vapor is prevented from entering the interior of the basement. A basement waterproofed without moisture barriers will continue to have moisture and dampness on the interior walls.
Diverters establish and maintain open water pathways to direct any and all water into a drainage system. Diverter products relieve hydrostatic pressure by facilitating water flow and removing resistance. Waterproofing systems without diverters are easily overwhelmed when heavy rainfall occurs.
Drainage products are placed under the floor in the basement to collect and discharge all storm water from the basement. It is very important that the drain system can accommodate a high volume of water. An undersized drain system won’t be able to handle the demand during heavy rainfall and flooding will occur.
All water must be properly discharged from the drain system. A pumping system is installed to remove all collected water from the structure. It is important to have a pump that is capable of removing the volume of water collected by the system. If a sump pump cannot meet the demands of the system, basement flooding occurs.
A backup system takes over pumping duties whenever power service is disrupted. Without a backup system, flooding will occur when power to the home is disrupted. A proper backup system will maintain the required pumping capacity of the system until power is restored.
The foundation walls must be inspected for any damage caused by hydrostatic pressure. If there is damage, the integrity of the entire foundation could be at risk. By permanently repairing any damage, the foundation will remain structurally sound.