When it comes to residential construction, there are several processes and aspects that might initially seem small, but are actually very crucial. One of the better examples of this is subgrade preparation.
Although subgrade is the lowest layer of a construction project above the soil, it serves as the base for which the rest of the surface layers and construction rest upon. Because of this, it’s highly important to not only overlook subgrade preparation, but take steps to ensure that is it prepared properly. Doing so sets the stage for a successful construction project that is built to last, and can defend against moisture and even shifts in the soil from other natural events.
When subgrade preparation is overlooked and done improperly, concrete can crack, and foundations can sink, leading to significant structural damage over time, as well as making your home and structures susceptible to water damage and flooding in areas such as basements.
Unfortunately, it’s common for many builders to overlook subgrade preparation for foundations of sidewalks, driveways, or patios, as well as residential structures. There are many reasons for this, including the fact that improper subgrade preparation may not show any effects for years.
Contractors are always responsible for preparing subgrade in the correct manner, and should always take every step carefully to ensure that it is compacted and spread while also using the correct fill dirt materials.
Failures in Subgrade
Ideal subgrade applications should have the correct sloping grade, be well drained, have a uniform bearing capacity, solid compaction density, and also be free of frost, sod, and any other organic matter. If not, cracks, slab resettlement, and overall structural failure can result.
There are many factors that can result in deficient and uneven subgrade. One of the biggest causes is soft, unstable soil mixed inside hard and rocky soil. Filling low areas or backfilling without appropriate compaction are big contributing factors as well.
Achieving Firm Subgrade
Firm and level subgrade can be created by first ensuring that soft or saturated soils and rocks are removed. These materials can result in breakdown of compaction over time, creating an uneven surface and affecting the layers above it.
Dirt is then pushed into low areas during the initial excavation, and away from other areas. It is very important for the soil to have the same density as it does in cut areas for the compacted fill in low areas.
It is worth noting that when building the subgrade, contractors should be able to properly identify what accounts for cut, and what is fill. Sometimes the workers who are operating the machinery can accidentally mix the cut and fill materials, which can lead to problems in the subgrade.
Soil for subgrade should be compacted where the moisture content is the highest. This can help to foster ideal levels of density in the subgrade, making it more stable. Soil that has been freshly excavated often contains adequate moisture content.
The highest levels of compaction can be achieved by using soil that is not yet dry, but also not wet from rainfall. If the the subgrade soil is compacted just after it’s been graded, there will be less pores in the soil that can absorb any water.
Finding Subgrade Soil
Finding an onsite soil for subgrade use can be a hard task. Soil quality is highly dependent on the location of the project. There are times that builders can find themselves using ideal soil that offers suitable strength for slab support, but this is a rarity. Because of this, dirt is often brought in from an outside source, such as having truckloads of fill dirt delivered.
Outside fill dirt often includes high-strength materials such as sand, gravel, and crushed stone, which can help offer additional support for slabs. When compacted in the proper manner, existing soils imported granular materials inside fill dirt can offer excellent support, but these materials must always be compacted correctly, or their advantages are lost.
Professional dirt grading assistance is always recommended to ensure that your property can thrive, whether it’s yet to be built, or currently standing.
Ensure Optimal Subgrade Preparation with Quality Fill Dirt and Grading Assistance
As we mentioned earlier, outside fill dirt is often needed to prepare quality subgrade. Professional grading assistance can also guarantee that your property is sufficiently built to withstand issues from collected moisture. For more on residential construction, please visit our residential services page.
If you need reliable free dirt delivery and professional residential dirt grading assistance, get in touch with Dirt Connections today by giving us a call or sending us a message online. We offer free dirt delivery to work sites, and also provide expert grading assistance to help ensure that your construction project is a success, resulting in a solid foundation to build upon.