Before anything goes in the ground, we find out what the ground will do. The first day on site is mostly about soil, water and safety, and the decisions made then last as long as the bunker.
Before the machines arrive
The site visit and soil evaluation come first. Test pits or borings show the soil type, how much rock there is and how deep the water table sits. The county soil survey from the USDA rates shrink-swell, corrosion risk and drainage. Those results set the burial depth, the bedding, the backfill and the waterproofing, and they are why the price is fixed only after the site visit.
Locates and permits
In Utah, state law requires a locate request through Blue Stakes, 811, before excavating. The 48-hour clock counts business days only, starting at 8 a.m. on the first business day after the request, and a locate request is valid for 21 days. Buried power, gas, fiber and water lines are marked before a bucket touches the ground. Building permits and inspections are pulled before work begins.
Layout
The footprint is staked to the engineered drawings: the shell, the entry, the escape route, the air intake and exhaust, the generator and fuel location, and the path of every utility. We set the shelter outside any flood zone; FEMA's guidance for in-ground shelters is clear that rising water and flotation must be designed out.
Excavation, done safely
A bunker excavation is deep. OSHA requires a protective system, such as sloping, benching, shoring or a trench box, in any excavation 5 feet deep or more unless it is entirely in stable rock, and one designed by a registered engineer at 20 feet or more. Spoil is kept at least 2 feet from the edge, and a competent person inspects the excavation daily and after rain. These rules protect the crew, and they also protect the walls of the hole that the structure will bear against.
Drainage and bedding
Before the shell arrives, the base is prepared: drainage that carries water away from the structure, then a level, compacted bed. For flexible structures such as corrugated pipe, the industry installation manual calls for backfill placed in layers and compacted, because the soil becomes part of the structure. The shell is then set by crane, waterproofed, and backfilled in lifts.
On the record
Most of this work is buried within days. Every step is photographed and filed in the client's private portal, so the drainage, the waterproofing and the backfill can be checked long after they disappear. See how your build is tracked and the full installation process.
Key takeaways
- Soil and groundwater are investigated before design is final.
- In Utah, Blue Stakes must be notified at least 48 business hours before digging.
- OSHA requires protective systems for excavations 5 feet deep or more.
- Drainage and bedding are built before the shell arrives.
- Every buried layer is photographed for the client's record.
This guide is general information to help you plan. It is not engineering, legal or water-rights advice, and requirements vary by state and county. Every Styrkholm project is designed by licensed professionals for the specific site.