In most homes, the basement provides a lot of useful space. However, in many homes, especially the older ones, the basements are leaky or damp making them unsuitable for profitable use.
Basement waterproofing refers to the materials or methods employed to eliminate or minimize water penetrating the basement of a structure. It involves the use of materials and sealants, and installation of drains. In some cases a sump pump has to be installed to collect and remove or re-channel water away from the basement.
Basement waterproofing is needed for structures that are built at or below the ground level. It is especially important in cases where ground water is likely to be retained in the soil, and elevate the water table. A raised water table causes hydrostatic pressure to be exerted on the basement floor and walls, which forces water through openings and cracks created on the basement floor and walls by the contraction and expansion of the foundation and wall joints.
What causes water leaks and seepage?
Water leakage and seepage in the basement may start as early as during the construction process and worsen over time due to a number of factors such as
Concrete. This is one of the most commonly used home construction materials. If the mixture is not allowed to cure properly or air pockets are not removed, the concrete can crack and allow water to gradually pass through the floor and walls.
Footings. These are horizontal pads that define the perimeter of foundation walls. If the footings are not laid deep enough or are too narrow they became susceptible to movement caused by soil erosion.
Downspouts and gutters. These are used to collect rain water and discharge it way from the buildings or into underground storm drains. If they are broken or clogged, rain water seeps into the soil near the foundation increasing the hydrostatic pressure.
The weeping tile system. The primary function of the internal weeping tile system is to redirect water to the sump pump pit, and the purpose of the external weeping tile is to prevent water from getting into the basement. When the drain pipes are damaged or clogged excess water exerts pressure on the basement floor and internal walls.
Subsidence. This is the downward shifting of soil near or under the foundation as a result of water saturation or the removal of groundwater.
How can the basement be waterproofed?
Evaluate the perimeter of the building
Ensure that the ground next to the foundation slopes away from it rather than towards it. If need be pile up dirt against the foundation to create a two inch per foot slope against the foundation. The top of the dirt should be at least six inches below the sill plate so as to avoid ground contact which may cause some building materials to rot.
Clean and repair drain pipes and gutters.
Ensure that the drain pipes and gutter are clean and in a good state of repair. The downspouts should discharge water at least five feet away from the foundation.
External waterproofing prevents water from getting to the foundation walls. This prevents the molding and wicking of building materials. External waterproofing is the only method the international Building Code (IBC) recognizes as sufficient to prevent structural damage due to water penetration. External waterproofing of the basement in an existing building starts with excavating the bottom sides of the footings. The walls are then white washed, allowed to dry and sealed with a waterproofing membrane. New weeping tiles are placed besides the footing.
Internal waterproofing using coatings is effective where the problem is minor dampness or where condensation is the primary cause of water damage. Normally, major seepage cannot be solved by interior coatings. If external waterproofing is not viable, tile or sheet coverings which conceal drainage structures are used to carry and drain the water. Interior drainage systems may include making a trench in the floor along the perimeter walls and installing weeping tiles. The weeping tiles are then connected to a drainage or sump pump. The new drainage is then covered with new concrete.
What are the benefits of waterproofing the basement?
- Protects and enhances the value of the property
- Basement waterproofing strengthens the foundations of the building and adds value to the home.
- Increases space in the home
- The basement can provide valuable living space in the home. It can be put to many uses like a bedroom, home gym, play space for the kids, office, etc.
- Save on energy costs
- Waterproofing the basement increases energy efficiency and reduces energy costs by sealing cracks and openings which cause energy wastage.
- Keeps the home healthy
- Water and humidity cause toxic molds to thrive. There are serious health risks associated with the constant exposure to this toxic mold.
- The basement provides a lot of useful space and waterproofing it adds value to the property, saves on energy costs and keeps the home healthy.