Foundation Drainage: Types, Design, and Components

Foundation drainage is a key factor in waterproofing a home. Without a foundation drain of some type, the foundation itself will be exposed to too much water and will eventually start to experience damage and deterioration. With foundation drainage, there are several different types, and they can all be installed at the time the foundation is put in. When there are issues with pooling water, foundation drains can sometimes be added after the fact. Let’s take a look at all you need to know about foundation drainage and ensuring the longevity of your foundation walls.

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What is a Foundation Drainage System?

A foundation drainage system is used to push water away from the foundation and ensure it does not seep in and deteriorate the foundation. This can be done through various methods, including a sump, downspouts, drain pipes, and french drains. The type of foundation system that homeowners choose to use can depend on the surface area of the land as well as the way water will drain from the roof.

The foundation drainage system will help with basement waterproofing, but it also ensures that the outside walls of the foundation are not continually soaked with excess groundwater.

Importance of Having Foundation Drainage

There are four main reasons that you will want to have a foundation drain setup for your home. However, each of these reasons will lead to various circumstances and issues that could be costly and dangerous.

The importance of having proper foundation drainage includes:

• Preventing water accumulation on the construction site
• Lowering the chance of significant settlement issues over time
• Decreased erosion of the soil
• Smaller chance of termite and pest infestation

Many homeowners are unaware of the damage that is being done to their foundation at any given time because of the lack of proper foundation drainage. Sometimes homeowners with basement walls can see the moisture in the wall, but others with a crawl space may have no idea how vital these perimeter drains are. Foundation repair is expensive, and protecting the home’s foundation should be done from the start.

Types of Foundation Drainage

Although there are unique solutions that many homeowners and builders will create to help collect water and then divert it, there are four main types of foundation drains. These should ideally be installed before drainage problems around the home’s footing.

Footing Drainage

A footing drain is placed on the exterior of the foundation wall. This is an exterior foundation drainage system that can be used in both residential and commercial situations.

When a drain like this is installed, it is then covered with gravel, and that allows for the water to slowly seep in and dissipate before ending up on your basement floor. Footing drainage systems are installed at the time the concrete foundation is installed, and that significantly helps the longevity of the foundation.

The footing drain will typically drain to a sump pump, the sewer, or simply the surface water. For footing drains to work effectively, it is best if they are installed lower than the top of the footing so that water can drain downhill. Sometimes a clog in a footing drain can cause issues in the drain system and create a moisture problem in the house foundation; with proper initial installation, the chances of this are less likely.

French Drain

The french drain is an exterior drainage system installed around the home’s perimeter. The perforations in the pipe help to move water away from the foundation and ensure there are fewer issues with pooling water.

With a French drain, there is significant backfilling done to crushed stone and rock to help keep the drain pipe in place and ensure there is less pooling of water. The French drain is not just used with foundations but also when doing landscaping projects or at the bottom of a downspout drain.

French drain installation can be a DIY project in areas where the main footing drain is not properly moving water away from the home.

Grading Drainage

Grading drainage is relatively simple, and it is again installed at the time that the home and foundation are built. This is essentially a way to catch runoff water and put it away from the concrete slab or foundation.

The grading drainage is installed on a slope that pushes water away from the structure and out towards the stormwater drain. With all drainage solutions, you may have to combine a few different options to properly move the water away from the home and back to the water table.

Sometimes grading drainage also needs a French drain installed.

Sump Pit and Pumps Drainage

In areas where there are heavy rains and a simple gradient or slope is not going to be enough to keep the home free of water damage, a sump pit or pump could be a great solution. This is essentially a catch basin for the water, but it will only accept a certain amount before it starts to pump the water out.

The sump pump has a trigger that will activate a pump when the water gets to a certain level. Once the pump is activated, the water can be pushed away from the building through the use of perforated pipes.

These plastic pipes help to move water away from the home and out to the storm sewer. Many older homes with basements have these and find them to be an effective drainage system. In addition, a drainpipe is installed around the foundation wall.

For those with a wet basement, putting in a sump pump can certainly help long-term with issues that come up, and these sump pumps can often be covered with your home warranty plan.

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All Components of Foundation Drainage

The main components of a foundation drainage system are essentially the same. Regardless of which type of drainage system that you decide on or have, the components include:

• A pipe that is typically perforated to allow for drainage
• Stone to surround the pipe
• Filter fabric that will prevent small particles and dirt from getting into the pipe and clogging it

Of course, there are also essential features included with grading and potentially a pump that is needed. However, almost all foundation drainage systems start with a pipe with perforations and backfilling materials.

The Design of Foundation Drainage

As we mentioned at the beginning of our guide, some foundation drainage systems will have unique design elements to ensure that the water flows properly and that the home foundation is protected in all areas. Here are some of the things to keep in mind as you design and build out your foundation drainage system.

Code Requirements for Drainage

Code requirements for drainage can vary depending on where your home is built. One very common requirement is that the drain must extend a minimum of 12 inches behind the outside edge of the footing. These drains may be wider than you first imagined, but this is to help the overall volume of water that will flow through them.

In addition, some codes will require that the top of the drain is not less than six inches above the top of the footing.

Drainage Boards

Drainage boards help to give water an easy path down to a footing drain. The drainage board can sometimes be called a drainage mat. If you do not use drainage boards to install the foundation, drain water can stay trapped around the concrete. These dimpled design boards allow water to flow instead of the pool.

Material of the Drain

The materials used in the drain are typically PVC pipe and gravel or rock is installed around it to help with water drainage. The perforated drain pipe can also be known as drain tile, even though it is a pipe.

Soil Moisture and Climate

Some areas have more significant issues with foundation drainage than others. In rainy climates, expect that foundation drains will need to manage a large amount of water. Most of the time, when homes are built, and foundations are installed, soil tests can be done to measure the amount of soil moisture and adequately prepare for drainage. In addition, if you think you have foundation issues, soil moisture tests can be done to check the levels and what can be done about moving water away from the home.

Trees and Other Obstructions

Tree roots will not only cause problems when installing a foundation drainage system but can also create long-term problems. Tree roots have been known to grow into drainage pipes, cut holes in them, and cause blockages. Using that geotextile fabric can help, but it won’t always be the case. Foundation experts know how to properly reroute foundation drainage systems to do their job, even with obstructions.

Placement of Foundation Drainage Pipes

The placement of foundation drainage pipes is another essential factor to consider. One of the main issues to look at here is the gutters. Homes should have some type of foundation drainage system surrounding the entire house. However, in areas where a downspout drains, you may need additional systems to ensure the water does not pool.

How to Properly Drain a Foundation

It is always best to have a professional come in and adequately drain the foundation for you. An expert is needed to get the job done with the number of issues that can occur if this is not done properly. However, these are the basic steps if you need to amend or add to your foundation drainage system after the fact.

Step 1: Dig A Trench

The foundation drainage system needs to be below the surface to work correctly. A surface-level drain will not collect enough water, and it will pool and push toward the house. The trench depth will vary depending on the amount of water you get and the type of foundation you have.

Step 2: Create A Slope Away From The Home

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Step 3: Level

Once you have your slope in place and it is moving away from home, you can level the area around it so that you are ready for the next steps of the process.

Step 4: Geotextile and Gravel Placement

The geotextile fabric and gravel placement will go into place next. It’s essential that both of these are a part of the process, as this is intended to be a long-term solution to your drainage needs. Always ensure that you have a few inches of gravel and still place the pipe so that it is at the proper level beneath the surface.

Step 5: Positioning of the Pipe

Place the pipe so it is balanced on the gravel and ready to start accepting water. You can place protecting fabric outside the perforated pipe to ensure dirt does not get into the line. Once this is in place, you can finish off the project.

Step 6: Finish and Monitor Effectiveness

You can not finish this process and level of your surface area so that it is completed. However, we highly recommend monitoring the effectiveness to ensure your drainage system is working. Sometimes if the process isn’t done correctly, the pipe will start to float up, or the drain itself can collapse.

Benefits of Foundation Drainage

The benefits of a foundation drainage system will be to ensure your foundation’s longevity, safety, and durability. This is achieved by:

• Preventing water pooling near the foundation
• Ensure that standing water is cleared up in a short period
• Reducing the erosion of soil around the foundation walls
• Lowering the chance of settlement and structural damage
• Keeping bugs and insects from spending time around the foundation walls
• Ensuring a dry basement without that wet and mildewy smell

Disadvantages of Foundation Drainage

As with any home-related project, there are some disadvantages to a foundation drainage system. Of course, in the end, you will have to find some way to manage and deal with the water, but these are a few things to be aware of.

• The price to install foundation drains can be higher than anticipated
• To properly put in a foundation drain, you must hire experts who know what they are doing
• Things like a sump pump will need to be replaced and maintained regularly
• The drains can get clogged and need amendments or changes to help them improve longevity
• Moving water into the sewer system can create runoff issues with contamination and environmental concerns

Where Does Foundation Drainage Go?

Foundation drainage has the ultimate goal of moving water away from the home. In most situations, this means moving the water to the storm sewer or to a sump pit, where it can then be moved to other areas around the home. The exact location of the drainage will depend on your home and how the water table and flood zone work.

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So, Is Foundation Drainage Necessary?

A foundation drain is necessary. Water moving towards your home’s foundation can cause major issues and setbacks. The best way to avoid this is to install a foundation drain. When your foundation for your home is installed, a foundation drain should be part of the process. Over time these drains may need to be amended or repaired because of damage with tree roots or filter fabric deteriorating, but the presence of a foundation drain will extend the longevity of your foundation.