How long does it take to build a bunker?
The length of time required to design and build a bunker varies significantly based on scale, complexity, depth, protection level, site constrictions, owner mandated secrecy / security protocols, regulatory agencies having jurisdiction, and whether it is a new build or a retrofit to an existing facility. A family-sized bunker is effectively the construction of a large an additional small home, engineered to far higher performance standards. A typical custom designed 10-person shelter will take approximately 3 months to design, 30-45 days to permit, and approximately 6-10 months to build.
For retrofitting bunkers installed within or beneath an existing home, the timeline is mainly driven by engineering challenges, contractor selection, and permitting. These projects typically require 2–4 months for design, engineering, and procurement, followed by 4–10 months of construction depending on excavation difficulty, access constraints, protection requirements, and system integration. Structural modifications to slab-on-grade homes, homes with difficult access, or sites with poor soils may increase these durations.
Some vendors offer prefabricated steel or modular bunkers; however, they are less sturdy and offer less protection than reinforced concrete. While installation might take only several weeks to one month once the unit arrives on site, the vendor waitlist can be several months to over a year. Production queues, shipping coordination, site preparation, and crane or excavation logistics all add to the schedule. Even with prefabricated units, proper installation, anchoring, ventilation integration, and backfill work require careful oversight. Additionally, prefabricated steel structures are limited to being buried with minimal earth coverage and can be damaged if vehicles drive overtop of them.
Large, high-end, or multi-level bunkers—especially those serving estates, compounds, or extended families—can require a year or more to design and often twelve to sixteen months to construct. These top-tier projects involve complex life-support systems, redundant power, A.I. counter measures, additional hardening of the structure envelope, blast engineering, and extensive quality assurance, each adding time to the completion schedule. For more information go to https://billionairesbunkers.com.
Overall, bunker design/build timelines are highly variable and must be planned based on site conditions, local permitting processes, vendor availability, and the owner’s threat hierarchy and operational requirements. Contact Hardened Structures to learn more about building a survival bunker or shelter.