Four Key Principles of Home Excavation
After staking your lot, you are ready to begin excavating for your project. In reference to home building, excavation is the process of digging a hole to prepare the land for a building structure. In most cases, this means preparing the land for construction of the structural concrete (i.e. footings, foundation walls, slab) upon which your home will be built. Excavation loosely refers to all cut and fill work performed by excavators. Cutting is simply digging the hole; whereas fill means bringing in material to raise the elevation of the building site. On sloped lots, a combination of both techniques is generally employed.
1) Principle of Topsoil Preservation
The topsoil on your building lot is a rich, valuable, natural resource. Before excavation begins, the topsoil should be stripped and stockpiled on the site to keep it from mixing with the less nutrient rich earth from the dig. When final grading takes place, the topsoil is redistributed to provide a lush base for any planned landscaping. Do not lot your contractor or builder remove the topsoil from the site. A common practice among production builders is to strip the land of topsoil at the very beginning of the project and then selling it for their gain and your loss. This leaves the new landowner with poor soil which requires years of organic amendments and integration with non-native soils to get anywhere near the same productive value.
2) Principle of Water Management
Water introduces numerous challenges to the excavation of your building site, and to your home in general, whether it comes from above or below. If your area is prone to lots of storms, having a plan to mitigate soil erosion while also keeping the construction site drained is essential. If your area has a high water table, you will need to account for this with a pump system. Good contractors will be familiar with the properties of land in your area and know the typical depth of the water table. If necessary, they will often dig a smaller hole separate from the primary dig, and use this to divert water from seeping and standing in the construction site.
3) Principle of Cost Containment
The size and complexity of the excavation determine the total cost for the project. Size is influenced by the footprint of the proposed structure (home, pool, patio) and the depth of the dig (basement, crawl space, leveling sloped lots). Contractors generally have a base price for the volume of cubic yardage being moved and they may assess a premium for complex situations. Other pricing models include hourly usage of the equipment being utilized. The heavier the equipment, the more expensive the rate.
Excavating during winter when the ground is frozen is more difficult and can cost more. If tree removal is required during excavation, this can also add cost. Soil conditions can be a factor as well. Loose porous soil is much easier to excavate than compacted clay. Compound this with the removal of large rocks and boulders, and the cost will go up proportionately. Same for pounding or blasting through solid rock. Supply and demand may influence price as well. More projects commence in the spring or summer and depending on availability of the contractor, you may pay a premium during peak season.
4) Principle of Experience (Tricks of the Trade)
- Photograph the job site before and after the excavation so you will always have a reference point.
- If your site is being prepared with fill material, proper compaction is absolutely critical for ensuring the structural integrity of your home. Verify compaction meets the specifications called for by a licensed civil or geotechnical engineer.
- Always call 811 before any dig to mark underground utilities and prevent service disruption to your future neighbors or create safety issues by nicking a gas line or power source.
- Always know the depth of the sewer line in the street, particularly if you are on a gravity based system. Cutting too deep may require the installation of a residential sewer pump or lift station, which can add cost to your total project and increase maintenance required on your home.
- Inspect the site after excavation to identify any trees damaged in the process or any variance from the construction specifications.
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