When waterproofing a basement, there are two essential components: the water drainage track and a sump pump. This method uses drainage channels that are installed along the inside perimeter of your basement walls. (Drainage channels are somewhat like pipes that go under the concrete floor.) The water travels along these channels and is collected and redirected to a hole dug in the floor, called the sump pump pit. The sump pump then expels it out of your home, usually 10-20 feet away from your foundation.
This method moves the water away from a point where it is pressing against your foundation and contributing to its decay. When homeowners first investigate waterproofing, they may view it simply as the method for removing the water from their basement. But through research, you will realize that alleviating the pressure that water generates against your foundation is also a critical part of this process. This pressure is called hydrostatic pressure.
The two main types of drainage systems are exterior and interior drainage.
Exterior drainage systems water from getting into your basement from the outside and protects your home’s foundation from water intrusion. This solution is more of a preventative method for keeping basements dry and protected.
Interior drainage systems, on the other hand, function as a remedial solution after water has already breached your home and become a problem. These internal systems are designed to direct water out of your home and away from the foundation after water accumulates. This is accomplished by pairing drainage channels with installation of a sump pump whose job it is to pump the water up and our of the home once it is accumulated by the drainage channels.
As a preventative measure, exterior water drainage systems are installed when a home is built. They function in the same way as an interior system; water works its way through the soil, then drains into a channel that drains away from the house.
The advantages of this exterior drainage are:
However, an exterior system only functions well for 15-25 years. They have a limited life span, because they are outdoors and subject to the whims of Mother Nature. Over time, sediment gradually works its way into the exterior drainage system. This creates clogs and then blockages. Once the drainage lines are blocked, they cannot be easily cleared- there’s 8+ feet of earth between you and the line. The only way to typically fix this is to excavate the system and replace it.
This is a messy, time consuming process. The contractor must dig 8-10 feet down in a trench all the way around the house, to fully expose the system In the process, everything in this area of your landscaping will be disrupted; your deck or porch will need to be removed, patios and walkways broken up, and landscaping will be uprooted and need to be relocated. Depending on the layout of your property, your garage may be affected also. This is especially true if it’s an attached garage.
Once the new exterior drainage is installed, and all of the landscape items have been re-installed or replaced, your house is good to go- for another 15-25 years. Costs for this process, on average, range from $25,000-$35,000 and take weeks to complete.
There are some drawbacks to interior drainage, as noted above. It’s inside your home where you have to see it, and it requires a sump pump that occasionally needs maintenance. These are annoyances. However, the net advantages of an interior system are significant:
Overall, when it comes to the health and safety of your home, our recommendation will always be to install interior drainage over exterior drainage.