How To Repair Basement Leaks: Where They Leak and What To Do

Repair Basement Leaks

It's not uncommon for your  basement to leak, but knowing how to repair basement leaks is an important first step. There are 7 main places where a basement will experience waterproofing problems, and knowing what to look for can help you get ahead of a potentially disastrous problem. In some cases you may need to hire a professional, but others leaks can be easily repaired yourself.

Types of Basement Leaks

  • Floor Cracks - Water can seep into a basement thru cracks that develop on the floor.
  • Cove Joint - This is where the walls meet the floor and when hydrostatic pressure increases water can seep into your basement. 
  • Foundation Walls - Frequently water will seep over the top of the walls of the foundation. 
  • Mortar Joints - A mortar joint is the area filled with mortar between concrete bricks or blocks. Because it's porous material this is a common leakage area. 
  • Porous Concrete - Concrete can become porous and allow water to seep thru it's surface.
  • Wall Cracks - When foundations settle or lateral pressure creates a wall crack, water is eager to seep thru these cracks. 
  • Window Wells - Seepage in window wells can be a common source of moisture in your basement. But it can also develop into a major problem if not addressed. 

How to Repair Basement Leaks

How to repair basement leaks can save you a lot of money and headache. In some cases, you'll be best to contact a professional, but even so, it's good to know what's involved with the repair.

Being proactive in repairing issues before there's a problem, as well as reacting quickly to seeping and moisture issues is the key to owning a leak-free basement.

Floor Cracks

Basement floors are typically 2 to 4 inches thick. Their purpose is to provide a solid base and keep water out. However, as the water table rises, hydrostatic pressure begins to build under the concrete floor. Eventually a crack will form and every time the water table rises water will seep thru your floor. 

Reducing the hydrostatic pressure that builds under your basement floor is the only sure fire way to resolve the problem. Installing a  drain tile system allows the homeowner to direct the ground water to a more suitable location. These systems relieve the hydrostatic pressure and prevents the water from putting pressure under the floor.

  • Don't forget to make sure your home's gutter system is moving the water away from your foundation. If possible it should be delivering the water into a drain system.

Cove Joint

A cove joint is a fancy way of describing where the foundation walls meet the cement floor. When hydrostatic pressure increases, water can seep in thru the cove joint. This is particularly a concern during times of heavy rain.

Many homeowners seal their basement's cove joints when they notice that this is the cause of the leak. However, doing so will not address the root of the problem. Since hydrostatic pressure is what's causing the cove joints to leak, and sealing them ​will not relieve the pressure, the best solution is to follow the advice given on floor cracks and install an interior drain tile system.

By installing a drain tile system the hydrostatic pressure will be relieved and future cracks and seepage will be minimized due to fluctuations in the water table. 

Foundation Walls

​Another common area where seepage occurs is the walls of the foundation. It's not uncommon to see gaps where the above ground structure meets the foundation wall. 

If the property does not have proper drainage, ​water may pool next to the foundation. Since water is always eager to find the path of least resistance, seepage can often occur thru this gap. 

The solution to this problem is best left to the professionals. An exterior waterproofing barrier can be installed to seal this gap and other potential leaking locations. 

Mortar Joints

A mortar joint is the area between the concrete bricks and blocks. Mortar is used to join the concrete blocks together. Unfortunately, mortar is a porous material that allows water to seep thru, it is also an area that can crack easily. Even minor foundation movements can cause the mortar joints to crack, thus allowing even more water to seep inside. 

Leaky stone walls could also fall into this category. The fix for stone walls is the same,  install an interior drain tile system and add vapor barriers to the walls.

Porous Concrete

Porous concrete is found in both older and newer foundations. It can form shortly after the concrete was poured, and it's usually caused by the concrete being poorly mixed.

Older homes experience this problem as well, since as concrete ages, it tends to become soft and can cause the wall surface to erode and crumble.

The best solution for this issue is to install an exterior waterproofing membrane (see Foundation Walls). However, there are other interior solutions that can be used. 

Wall Cracks

Non-structural wall cracks are one of the most common types of basement leaks. They frequently occur when poured concrete settles or by lateral pressure.

Filling the crack with a concrete seal is generally the best way to solve the problem.​ There are several products on the market that you can use if you want to do the work yourself.

Window Wells

There are a few possible ways to repair leakage from window wells. The first, is to see if your window well has a drain. If it does, the solution may be as easy as cleaning or replacing the drain. If it doesn't have a drain, you may consider installing one and directing the water to drain tile which can direct it away from your foundation.

​There's also the possibility that the leak could be coming from the window well liner. These liners can separate and create a gap between the foundation wall and the window well. Frequently, they can be reattached. But if it's clearly damaged you may need to purchase a new one.