Level the ground for Your New Metal Carport or Custom Metal Building

By Scott Kyles   |   Posted In: Installations

steel building structure

So, you’ve chosen a quality metal carport and picked out the perfect spot for it. What now? Whether you’ve purchased a metal carport kit or are planning on having it professionally installed, it’s important to level your site before the first pole is placed.

Leveling Your Site
Site Leveling

Why Leveling Your Site is Important

If your site is unlevel by more than four inches, you’re asking for trouble. There are no benefits to having your custom metal carport or building installed on an unlevel site. However, there are numerous disadvantages and issues that this causes.

Here are three major issues caused by installing your building on the unlevel ground:

    • Your building will appear uneven.

While this is an aesthetic issue, is it something you want to live with? Your building will not have the same beauty that a custom metal building that is installed on level ground will have. No one wants that, right?

    • Your building will not function properly.

Beyond a diminished aesthetic appeal, a prefab metal building that is installed on an unlevel site will not function well. Uneven foundations make it impossible for doors to close correctly. There will be gaps that will allow water and all kinds of creepy critters to infiltrate your structure.

    • All warranties are voided.

If you choose to have a building installed on an uneven foundation, if the process is even possible, you will automatically void all of your warranties. We will not guarantee the longevity of our structure if it is not installed properly.

Another major disadvantage of having an unlevel site is that it may not be possible for our installers to put up your custom steel building to begin with. If this is the case, they will have to leave, and your installation must be rescheduled. Not only will you lose time, but you will also lose money because you will have to pay for both installation trips because of the inconvenience to our crew. You will be expected to have your site leveled by the rescheduled date.

Preparing Carport Base
Preparing Carport Base

Carport Base Options

Depending on what you will be using your carport, garage or storage shed for, there are a couple of foundation options to choose from:

Ground Carport Foundation

Ground foundations are the easiest and most budget-friendly option. There is no additional installation process for this foundation type; all you have to do is level your site! It should be noted that we do not recommend storing objects of especially high value or that could easily be damaged by mud in steel carports with this foundation type, as any precipitation will cause mud to form.

Concrete Carport Foundation

A concrete slab has many benefits for your steel carport. Unlike using a dirt floor or gravel, concrete does a better job of protecting your precious storage. For example, tires that sit in standing water or mud can suffer unnecessary wear and tear, which can become costly over time—especially if you are sheltering a larger vehicle. Concrete will keep your contents dry and clean.

Gravel Carport Foundation

This is a simple gravel base for the carport floor. Over time the gravel will shift and develop trenches which can be easily re-leveled; this is a more cost-effective option if you are on a tight budget or if you are sheltering items that don’t require as much TLC. This is a great middle-ground between a dirt floor and a concrete foundation.

Asphalt Carport Foundation

Asphalt foundations are a great option if you live somewhere the ground stays damp, or you experience frequent rain. This type of foundation won’t wash away or allow mud to form. It’s similar in security to a concrete foundation, but it will require slightly more maintenance. Asphalt needs to be sealed at least once a year.

Level an Area for Your Metal Carport
Level an Area for Your Metal Carport

How to Level an Area for Your Metal Carport

1- Check for Utility Lines and Clear the Area

Check with your local utility companies before you get started to make sure you don’t run into any gas or water lines. As soon as you are cleared, you can start by removing shrubs, grass, and other plants in the area.

2- Measure and Mark the Area

Using measuring tape, measure the area where you will be installing your metal carport. Be sure that the area you are measuring is slightly larger than the actual structure. We suggest using spray paint to mark the perimeter.

3- Place Stakes at All Four Corners

Place the ground stake in your first corner, then using a measuring tape, measure to the second corner. Place the second stake in the ground. Repeat the process until all four corners are marked.

If you are going to lay a concrete pad down, you will have to square your site. (We won’t cover squaring in this post, but instructions are readily available on the web.) Otherwise, if your site is well “squared,” you should be good to go.

4- Level the Sides with String or Twine

Once you have staked your four corners, find the stake that appears to be at the highest point. Measure a set number of inches from the ground and tie your string there. (We will use four inches for this example.) Choose your next stake and tie the string at the height where it seems to be level with the height of the first stake. Place a line or string level in the middle of your string and adjust the string on the second stake until the bubble in the sight glass of the level is in the middle.

5- Measure Your High/Low Points to Find the Difference

Once your string is level, measure the high point (which should be four inches) and your low point, and figure the difference. For example, if your string is four inches at one end and six inches at the other, you have a difference of two inches. This would be an acceptable slope for a basic metal carport design.

For metal barns or other metal buildings, you would need to add dirt to the low point or remove dirt from the high point to eliminate the slope. This is so your structure can be anchored securely. Repeat this step for the other three corners to be sure that your entire site is level. Now you are ready for your gravel or concrete.

How Much Does It Cost to Pour a Concrete Slab for a Carport or Metal Building?

Ideally, pouring a concrete slab for a carport or metal building should be done by a certified professional.  The type of foundation chosen for a carport or metal building is dependent on the type of environment.

Concrete is always a good foundation choice, but if you live in a rainy or moist area where the ground always stays damp, it might be difficult to get concrete to set up properly.  In a situation like this, gravel would be a better choice.

Check building codes

It is vital that you clarify what your local building codes are to determine the overall costs of placing a concrete slab. Your area might require special access or permits to pour a concrete carport slab or metal building slab.

To be safe, check with your state and local municipal authorities so that they can tell you what steps to take according to their regulations. It is best to create site-specific drawings with details on the building materials and how the foundation will be built. These drawings must be approved by a state-licensed engineer.

Sizing of the concrete slab

The size of the concrete slab for the carport depends on the measurements of the carport chosen; the slab dimensions should align with those of the carport. The area marked for the concrete slab should be somewhat larger than the actual building, however.

Type of slab or foundation

There are three types of slabs you can pick from, these include:

  • Edge offset – this is the same measurement as the outer dimensions of the building with an additional 5 inches added.
  • Notched edge offset – like edge offset, but the offset requirement is slightly less.
  • Edge flush – the slab is the same as outer building dimensions.

All of these slabs require footers at least 4 inches thick, and the footer width must be at least 12 inches.


Depending on the type of foundation you choose, you’ll need a specific type of anchor. This can bring up the cost of placing a carport slab.  Rebar anchors are used for gravel foundations, while concrete anchors are used for concrete foundations. Concrete anchors are slightly more expensive, so keep that in mind.

Be sure to watch our helpful video tutorial that guides you through the process.

Carport Central Makes Your Dreams Come True

Having a level installation site is important, but it’s also important to buy your custom metal carports and prefab metal buildings from a high-quality provider. That’s why you should trust Carport Central with all of your metal building needs. We provide products that are produced in the United States and made from the best materials available. Not only that, but we also pride ourselves on having excellent customer service. If you have any questions at all, don’t hesitate to call one of our friendly building specialists at (980) 321-9898. What are you waiting for? Carport Central is here to make your metal building dreams come true today!


  • Scott Kyles

    Scott Kyles serves as lead content writer and marketing consultant for Central Steel Group, the parent company of Carport Central. He’s been speaking to the metal buildings industry and its customers for over 5 years, and also holds professional certifications in secondary science education, training, and customer experience.

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