In this awesome guide, you’re going to learn almost everything you need to know about fill dirt.
What is fill dirt? What is it used for? Where can I find some?
Fill dirt might sound like a boring topic, but it’s very important. Picking the wrong soil can lead to costly and dangerous problems.
It’s important to know the basics, which is why we created this resource. We cover a lot of ground, so skip ahead if you have a specific question.
What is Fill Dirt? What is Fill Dirt Made Of??
Fill dirt levels or elevates the ground by combining natural materials like subsoil, rock, sand, and clay. In simple terms, it fills spaces with any type of dirt.
People use fill dirt for various purposes, and certain projects demand soil of superior quality compared to others. This is why you will see different types of fill for sale, such as clean fill, certified fill, common fill, and backfill, among others. We explain each of these below.
When looking for fill dirt near you, it’s also important to note that soil from Los Angeles, CA is very different from fill in Boston, MA or Miami, FL .
But let’s start with a quick example. When a builder prepares land for a new home or structure, it’s important that the ground below it will not shift over time. If the subsoil moves, the foundation supporting the building can crack or fail completely. Any old dirt can contain roots, plant nutrients, animal remains, or other types of organic material. Organic material decomposes over time, leading to this issue of shifting soil. That’s why it’s crucial to choose the right type of fill dirt.
Types of Fill Dirt
You now have a basic understanding of what fill dirt is, but there’s more to know. The term fill dirt is really a catchall for the many types of dirt , including soil, back fill, and septic fill. Below, we break down each type of fill, including what it is and what it can be used for.
What Is Clean Fill ?
Clean fill refers to dirt that is free of materials dangerous to humans, animals, and the environment. The label “clean fill” does not imply that the dirt undergoes screening or is free from debris and organic materials. It simply means the fill dirt is environmentally clean and free of hazardous materials including:
- Corrosives: These are chemicals and highly acidic substances, and soil containing corrosives will damage or destroy metals (beams, pipes, etc.) when they come in contact.
- Combustibles: This includes any materials that easily catch fire. Potting soil can be combustible, as odd as that may sound.
- Radioactive Substances: Radioactive substances are more common than you might think, and it’s important to keep them away from environments with people and animals.
- Noxious Materials: Materials that produce offensive or hazardous fumes are classified as noxious. Soil with things like metals and bacteria in it can become noxious.
What are Clean Fill benefits?
Clean fill enhances eco-friendly projects like landscaping. It levels park grounds and serves as flowerbed subsoil. Construction employs it for embankments, road shoulders, and parking lots. With so many uses, clean fill dirt is one of the most popular options.
You might see Clean fill referred to as certified fill. An expert, such as a soil engineer, tests and verifies it, ensuring freedom from debris and toxic substances.
Cheap dirt, known as common fill, is usually dug straight from the ground and delivered without screening, cleaning, or testing. Because of this, it usually contains a lot of clay, as well as rock and plant roots, making it difficult to work with by hand.
What do people use common fill dirt for? They mainly use it to fill or elevate vast areas of space. It requires construction equipment to move and spread.
Common fill is inexpensive to buy and sometimes offered for free by construction companies digging up grounds for projects.
What is Screened Fill Dirt?
Screened fill dirt is clean fill that undergoes a screening process, using a dirt screening machine to separate debris larger than approximately 5/8 inch. The screening process adds to the cost, but it’s very helpful if you plan to spread the fill using a wheelbarrow and shovel. That’s because fill often contains clay and heavy rock, which takes up space and is difficult to move.
What do people use screened fill for? Screened fill serves a purpose in home landscaping projects, as it involves clean fill that undergoes screening to remove debris larger than approximately 5/8 inch.
For example, imagine you have a hole in your backyard that you want to fill in for a lawn or garden. You can easily shovel and spread screened dirt to fill the hole, and then cover with topsoil. The screened fill would provide a strong subsoil base, and the topsoil would provide the nutrients required to grow a lawn or build a garden.
What Is Select Fill ?
Select fill undergoes a two-step process: first, screening to remove large debris and organic material, followed by testing by a soil engineer to ensure it meets specific project requirements. The fill itself is usually a combination of clay and gravel because these strong materials are less likely to shift over time. Parts of the country may use different types and amounts of materials to produce select fill based on what’s safest for building in that region.
Select fill serves a distinct purpose. It undergoes thorough screening and testing, making it suitable for placement beneath concrete foundations in buildings. This is crucial because it ensures stability over time, thereby guaranteeing the structural integrity of the building above.
Select fill is normally the most expensive type of fill because of the process that goes into creating it and testing its quality.
What is Topsoil?
Topsoil is a mixture of compost and sand that contains the nutrients necessary for growing things. Topsoil, designated for the upper layer of ground, is vital in landscaping and gardening. Positioned above subsoil, it plays a crucial role in fostering plant growth and enhancing the overall soil quality.
Now, let’s clarify the facts about topsoil. It’s important to note that adding a layer of topsoil to fill dirt is not sufficient. While topsoil contains nutrients, it’s not a substitute for fertilizer.
To cultivate successfully, it is essential to thoroughly blend the layers of soil in use. Here’s what experts recommend:
- Blend a few inches worth of subsoil and topsoil together. Roots will have trouble growing down into the subsoil so this transitional layer will help.
- Test the composition of your topsoil for things like sand and clay. This important step will help you figure out which nutrients your topsoil is lacking.
- Fill in a layer of topsoil.
- Find a fertilizer or soil containing the nutrients missing from your topsoil, and mix the two soils together. Then spread this mixture through your soil using a rake, which will create an even layer that contains the nutrients necessary for growing plants.
Other Types of Fill
Fill dirt has many purposes and can be made from a lot of different materials, which is why you might see other names for it. Below, we define the many other terms for fill dirt used by companies around the country:
- Compost, Manure, and Fertilizer: Enriched with organic materials, compost, manure, and fertilizer supply vital nutrients to plants. Compost, a mix of decomposing foods and plant life, along with manure, animal dung, and fertilizer, a human-made soil crafted with precise nutrient levels, ensure optimal conditions for plant growth.
- Rock Fill Dirt: This type of fill contains much higher quantities of stone, which is common when digging dirt from great depths. Because these rocks are often very large and extremely heavy, this type of fill is best for filling large holes. It’s not suitable for growing plants so it will need to be combined with other soils if used to fill large holes in a lawn, such as an old swimming pool.
- Septic Fill Dirt: This type of fill is normally a mix of carefully screened and tested sands and is used to fill in the area around septic tanks. It’s important that this space does not retain moisture, which would cause the ground to shift and sink around the septic tank. Septic fill rejects moisture and protects your lawn.
- Backfill: Backfilling is the process of filling a hole with the dirt that was dug out of it. For example, you can dig up your yard to install underground cables or pipes, and then backfill the dirt to cover them and level off the area. The dirt itself would be considered backfill.
Where Does Fill Dirt Come From?
Now that you know the different types of fill, you might be wondering where all of this dirt comes from. The obvious answer is that fill dirt comes from the ground. Whenever land is cleared for a home, building, road, parking lot, or anything else, there’s a lot of dirt that needs to be removed from the scene. These crews will load the dirt into a truck and look for a place to dump it.
You might not know that companies clearing land can’t dump dirt wherever they want; they are responsible for dumping it legally. They have a few options: find another construction job site or individual in need of dirt and delivery it, offer it to a landscaping company, or pay to dump the dirt at a city-approved location such as a landfill.
Speaking of landscaping companies, these are a great source of fill dirt. Landscaping companies often excavate or accept free dirt from the local area, clean it, and sell it for a profit. Although fill dirt from such companies may be pricier, it’s important to note that the dirt undergoes screening to remove debris and testing to ensure it’s free of harmful waste.
What is Fill Dirt Used For?
We’ve discussed the common uses for the different types of fill dirt (above), but here’s a list of the various things people use fill dirt for:
- Elevating property for commercial and residential building
- Replacing low-quality soil with strong subsoil fit for building (homes, structures, etc.)
- Landscaping
- Gardening
- Road shoulders or embankments
- Parking lots and garages
- Filling in unwanted holes (think old swimming pools, septic systems, etc.)
- Erosion control and foundation repair
- Building levees for flood protection
And this list is just scratching the surface!