If you've ever driven past a new subdivision just getting started, you've likely seen a fleet of earth-moving equipment, multiple colored stakes in the ground, and the beginnings of streets, sidewalks, and foundations. These are the tell-tale signs of the building site being prepared for construction.
Site preparation includes several steps. A survey comes first. Topographical features -- trees, streams, rocky outcroppings, relative elevations, and open areas -- are carefully marked, providing the basis for everything that follows. Property lines must be located precisely to confirm setbacks (the allowable distance between a structure and a property line) in compliance with local codes. Streets and sidewalks are mapped and flagged. Then the surveyors stake out the location of the various underground utility conduits through the neighborhood and to each house. In the case of a single house under construction, the existing utility services in the neighborhood must be located and the connections to the proposed house carefully plotted. Finally, a soils test is ordered to help determine the type and design of the foundation construction.
Most, if not all, of this information is mandated by the local building authority. Copies of the surveys and tests, usually signed and stamped by a registered professional engineer, must be attached to the proposed construction drawings and submitted for permits or approvals from that authority.
Once those steps are taken and the plans are approved by the building department, the next "site prep" step can be taken. The location of the foundation or footprint of the home is staked to provide a guide for excavation. Typically, the stakes and batter boards (which demarcate every corner or turn in the layout) are connected by nylon strings to outline the exact perimeter of the foundation to be built.
Then backhoes or excavators can get to work, digging ditches to extend existing or new utility conduits -- for electrical, plumbing, natural gas, etc. -- to serve the house (or houses). Foundations are excavated using the staked-out lines as a guide. The plans will call for footings and -- according to individual designs -- a crawl space, full basement, concrete slab, and/or perimeter foundation walls in preparation for concrete forms, blocks, or other materials to support the main floor.
Every new-home project requires these site prep steps, and it is important for our homebuyer clients to understand this phase of the job to track our progress and get a complete picture of what is required to build their new home.