Waterproofing & Drainage Systems
SOURCES OF WATER:
There are two main sources of water that can enter a basement if not managed properly; storm water (from above) and groundwater (from below). Groundwater comes from rain, snow and hail that soak into the ground. Gravity pulls the water down, through soil, gravel or sand until it reaches the point where the earth is saturated. This area is called the saturation zone and the top of this zone is called the water table. The water table can be deep in the ground or fairly close to the surface, depending on the amount of water coming from above and/or any underground sources of water.
Without properly working eaves troughs, downspouts and grading, storm water can enter your basement through a foundation crack or add to the ground saturation surrounding a foundation.
Groundwater can become an issue for your foundation when the water table rises above the level of the footing and begins to pool around the outside walls of your house and under the basement slab. Because water has the natural tendency to try to equalize by creating downward pressure at its highest point (outside the perimeter of the wall) and upward pressure at its lowest point (under the basement floor) it will find its way up through any cracks in the floor or through the joint where the wall and floor meet.
An ideal system for managing and controlling water in around your house includes a waterproof, seamless elastomeric membrane applied with a drainage board system, weeping tile system (exterior and/or interior), and sump pump. Properly functioning eaves troughs with downspouts and good grading sloping away from your house are also important components.
A – Elastomeric Membrane
Elastomeric membrane is sprayed to the outside of the foundation to form a waterproof barrier that can stand up to hydrostatic pressure. Elastomeric membranes can also bridge any current, or future, hairline cracks in the foundation.
B – Foundation Board
Our foundation board is used in conjunction with the elastomeric membrane. It aids in directing water down to the weeping tile system, protects the membrane during back-fill and provides a thermal break and R5 insulation. The foundation board also absorbs some of the compressive forces from the soils around the foundation.
C – Weeping tile (interior and exterior)
Exterior weeping tile is installed around the perimeter of the house next to the footing. It collects water from around the footings, draining it into a sump basin where it collects until it is pumped out by the sump pump. Our interior weeping tile is installed in the same fashion but around the inside of the footing. It also drains into the sump basin and is then pumped out by the sump pump.
D – Sump pumps
Sump pumps remove the water that has collected from the weeping tile. The sump liner is the holding tank for the collected ground water. It must be perforated and installed in a bed of washed rock.
E – Grading
Maintaining good grading around your house is essential to help prevent damage to foundations. A negative grade sloping away from your house using clay soil up to the last few inches and covered with top soil is the best. Creating a swale (a depression that slopes or is graded out to the street) between properties also helps to direct water towards the storm sewers.