Do Concrete Slab Homes Need Gutters: What Building Code Says

The success of any construction project involves the details. When building a concrete slab home, one of those details might include gutters. What does the building code have to say on the subject?

Local building codes may require gutters for concrete slab homes if local conditions make roof runoff hazardous to the slab. Those hazards could include areas of slow drainage, collapsible soil, or excessive rainfall. Local building codes may require gutters and downspouts when roof runoff close to the slab would impact the foundation’s integrity.

Along with determining what the building code may say in your local area, it is also essential to consider why gutters and downspouts are beneficial. The code would set the minimum standard for any construction project, but it does not cover all possible solutions. Roof gutters are sometimes needed for aesthetics or perhaps for the comfort of those living in the home.

It is also beneficial to investigate why gutters are necessary for your home. The state may have location-specific building codes, and they would provide the minimum standards for what any construction project may require.

Looking further into the building code, you might find that there are county, city, or even community guidelines that would make the use of gutters necessary on your home.

One other thing to consider is that not all building codes are absolute. There may be instances when the building code calls for gutters if the correct criteria are met, such as the type of soil, annual rainfall, and the slope of the land near the home. In that way, the answer is not always a definite yes or no, but it may differ, depending on local circumstances.

Why Are Houses Built Without Gutters?

In almost all areas, installing gutters would be beneficial for slab homes. There are also times when you may not need to install roof gutters if it would not impact the home negatively. 

There will be times when roof gutters are a building code requirement. When they are not a requirement, it is up to the homeowner to determine if they should install roof gutters.

Here are some common reasons why homes do not include roof gutters:

  • Good soil drainage: Different types of soil will drain at different rates. In some cases, the existing soil may be more compacted, and it will hold on to the water from roof runoff for more time. On the other hand, loamy soil, typically a mixture of sand, clay, and silt, tends to drain quickly. If you live in an area with good soil drainage and the building code does not mandate that you have gutters installed, you may be able to forgo their use.
  • Arid regions: For areas with low annual rainfall, roof gutters may not be a requirement. Again, you would always check the building code to see if they were necessary. If you live in an area where rainfall is low, the amount of water affecting your slab will be negligible.
  • Areas with natural runoff (landscaping drainage): Some slab homes include sufficient natural runoff. Proper landscaping drainage will be able to handle any rainwater that comes off the roof. Both the slope of the land and existing landscaping can facilitate the removal of groundwater quickly. When designed properly, this can do more than provide proper runoff. It can also add to the curb appeal and beauty of the home.
  • Roofs with adequate overhang: One other thing to consider when deciding if you are going to use gutters or not is the overhang of the roof. In some areas, it is common to have roof overhangs that are 10 inches or more. In these cases, it may be possible that the typical roof runoff would land far enough away from the slab that it would not impact it. In areas where roof overhangs tend to be short, the runoff from the roof will land closer to the slab and could compromise it.
  • Multiple problems: When the building code does not require roof gutters, consider all factors carefully. In some cases, it may be a combination of design options that would keep the integrity of the slab protected when it rains. You may also need to calculate how much water is coming off the roof and where it is going. A contractor or architect can help you make that determination.

Do Gutters Help Your Foundation?

If the drainage around your home is sufficient, or if you live in an area where annual rainfall is low, you may not see much benefit from having gutters. Even so, anytime you have water near the foundation, you run the risk of damage. In some cases, the damage may be extreme, and it could even compromise the foundation and make the home unlivable.

In most cases, you will find that gutters are beneficial to the homeowner in some way or another. As far as benefiting the foundation is concerned, it has to do with soil erosion at or near the slab. Any time water is impacting the ground; the soil could be compromised. Soil erosion could cause instability in the foundation over time, and gutters are a good way to prevent this.

This problem may not manifest itself immediately, and it could happen under the surface. That is why you should consider the use of gutters if local conditions do not cause the water to drain away naturally.

The most common reason why an erosion issue occurs is due to roof drip line erosion. This type of problem occurs directly below the edge of the roof when there are no roof gutters. Over time, having rainwater hit the same area could eventually erode it and could impact the slab.

It is also important to note that, even if you have gutters installed, you may still have a problem known as gutter discharge erosion. As the name suggests, this affects the ground at the bottom of a downspout. Although it does not have as widespread of an impact, it does tend to have a similar effect because the issue occurs more quickly due to more water impacting the area.

That is why you should consider more than just the gutters installed on the home. The types of downspouts that are in use may protect the slab.

Does The Proper Downspout Protect The Slab?

A properly installed downspout will provide extra protection for the slab. Most homeowners and DIY enthusiasts will consider the possibility of installing a gutter system. In most cases, it would include attaching the gutter near the roof and installing downspouts. However, if you use a standard downspout, it could compromise the foundation of the home.

As the water pours out of a downspout, it will saturate the immediate area near the downspout discharge. Something similar would happen when any root runoff was landing near the foundation. Water would soak the area, but the impact is extreme. Additional problems occur because of the concentrated water at the discharge.

For that reason, give close consideration to the type of downspout and its location. Doing so will keep the water from discharging close to the home. Most downspout options are purely aesthetic, but there are some options. Those options would include some attachments for existing downspouts. Once downspout attachments are connected, they can divert water away effectively. Here are a few options to consider.

Downspout Extensions

This downspout addition discharges the water at least 5 feet from the house, as the name would suggest. In some cases, such as in areas with poor landscaping drainage, it may be necessary to extend the downspout further than 5 feet.

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The biggest issue that most people have with downspout extensions is that they are typically unattractive. Landscaping in the area helps to improve aesthetics and improves drainage. There are also some options for downspout extensions that unfurl when roof runoff occurs. They can then be rolled up near the downspout and out of sight.

Rainwater Harvesting System

This system diverts the roof runoff away from the house and saves the water in a container for later use. Typically, this harvesting system collects water for irrigating landscaping, washing cars, and even flushing toilets. With the proper water filtration in place, a rainwater harvesting system can also store water for human consumption.

What Are The Benefits Of Gutters For Slab Homes?

It is beneficial to look beyond the building code and consider why they have those codes in place. Those reasons may include benefits to the property owner, and that is true of roof gutters.

When you consider the benefits of roof gutters for slab homes, you begin to see why they should be a part of the building project in most cases.

Here are 3 of those benefits:

1. Foundation Integrity: Water can slowly erode the foundation when discharged from the roof too close to the house. This problem does not typically occur all at once. In the absence of gutters, water could accumulate around the foundation, causing small cracks to form. As these cracks form, they tend to fill with water, causing them to crack even further. Eventually, it could compromise the foundation and could even make the home unlivable.

2. Curb Appeal: Beyond the protection that gutters provide to the foundation, they also add value to the property. Admittedly, most gutter systems are not beautiful to look at, but they do add curb appeal in that a potential buyer will notice the upgrade. Roof gutters are an inexpensive option compared to many other home upgrades. Weekend warriors can install them on their own, or a roof gutter service can install them quickly.

3. Personal Comfort: Adding gutters to the area above you enter and exit the home can certainly add to your comfort. If the roof runoff lands in front of the door, the last few feet between you and your car are typically going to be wet. Something else to consider is the water running off the roof. When water hits the sidewalk or porch in front of the door, it leads to splashback. Excessive splashback could enter the home at the threshold and result in damage.

When considering personal comfort, it is not always necessary to add gutters to the entire home. Typically, adding them to the area above where you enter and exit will be sufficient.

What Happens If A Slab House Has No Gutters?

Finally, we will consider what happens if you have a slab home and decide to forgo the installation of gutters.

The lack of gutters in a slab house could weaken the home’s foundation as time goes by. Also, if you installed no gutter yet, the building code requires one, you might get in trouble with the law.

Perhaps the first thing to consider is if you are choosing to ignore any building code that would require the use of gutters. A lack of roof gutters might not be a problem on an existing home if the building code did not exist when built. On the other hand, stick closely to current building codes when doing any extensive remodel or new construction.

Ignoring the building code can result in some significant trouble for you. A fine or halt of construction can happen for not abiding by local building codes, and you’ll still need to bring the house up to code. In addition, it may be necessary for you to make additional upgrades to the home if you don’t follow the code correctly. Getting caught could result in an unexpected output of money and a lot of extra work. Installing roof gutters when required by the building code avoids those problems.

Many communities will actively watch for any violations of the building code. If they see construction taking place, especially if you don’t pull necessary permits, it could lead to serious problems for the homeowner.

Even if you were to get away with not having gutters, the building code is typically in place because it protects you and your home. Without roof gutters, you may be compromising the foundation over time.

Gutters are one of the least expensive options for upgrading the home. Installing gutters is a common DIY project that even weekend warriors can tackle. Hiring a contractor or gutter specialist can also be beneficial because for the job to run quickly and smoothly. Think about the benefits and look into the building code when considering installing gutters on your home.

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Hubert Miles

I've been conducting home inspections for 17 years. I'm a licensed Home Inspector, Certified Master Inspector (CMI), and FHA 203k Consultant. I started HomeInspectionInsider.com to help people better understand the home inspection process and answer questions about homeownership and home maintenance.

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