Basement leaks are common, and with few exceptions, are to be expected at some point in the lifetime of your home. This article explains why basement leaks occur and what to do about them.
Below you will find a few examples of what basement leaks look like.
What basement leaks usually look like
Clearly, no one enjoys having a wet basement and having to fix a leak in their basement. Fortunately, basement leak repair is often fairly inexpensive and, in most cases, can be done from the inside (which is especially important during winter months).
Why basements leak
Basement leaks are essentially the result of hydrostatic pressure in the soil being relieved by voids in the concrete walls of your foundation. This pressure that the water exerts against the building envelope is the main cause of water coming through the foundation walls or up from beneath the basement floor. When there is a cavity in the concrete wall, such as a crack, water will take the path of least resistance and flow through the opening.
In general, leaks in poured concrete foundations typically result from cracks, tie rod holes, honeycombing and other voids in the basement walls.
Concrete block foundation leaks occur more frequently than for poured concrete foundations. This is the result of the development of cracks in the blocks themselves or the mortar joints that bind the blocks together. This cracking occurs as the foundation settles or over time, and due to foundation fatigue from the expansion and contraction of the soil surrounding the foundation, due to changing moisture levels and temperature changes.
As a result of this cracking of the cinder block walls, when the hydrostatic pressure is high enough, water is able to penetrate these cracks thereby filling up the hollow blocks. Blocks that are full of water are responsible for seepage into your basement. The illustration below captures the travel of groundwater through a cinderblock foundation.
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How basement leaks are repaired
The good news is that 99% of the time basement leaks can be fixed either from the inside or the outside. The suitability of each type of repair typically depends on the source of the problem and accessibility of the repair area.
For poured concrete foundations; 99% of leaks coming from the walls can be repaired internally through injection. Alternatively, when injection is not possible the wall can be excavated and waterproofed on the outside.
In the case of concrete block foundations, most leaks can be repaired internally by installing an interior perimeter drain system or externally in a similar manner to poured concrete foundations.
How much it costs to fix basement leaks
The usual assumption concerning foundation repairs is that they will be very expensive. This however is not necessarily the case; particularly when dealing with poured concrete foundations. Poured concrete foundations are typically much less expensive to repair thanks to the pressurized injection process. In fact, basement leak repairs for a poured concrete foundation can cost as little as $175-$650.
Basement leak repairs on concrete block foundations are more costly due to the nature of the repairs. As larger areas need to be repaired, repairs are not as quick as for poured concrete foundations and are much more labour intensive. Concrete block basement leak repairs usually cost upwards of $3000.