Guides
Bunker guides
Straight answers to the questions people ask before they buy a bunker: cost, size, air, water, power, digging, delivery and permits. Every guide cites its sources.
CostWhat a steel bunker costsWhat a modular steel bunker costs in 2026, from $251,900 for two cubes to $766,800 for eight, and what moves the price up or down.Read the guide PlanningHow big a bunker your household needsHow to size a bunker for your household: floor space per person, fresh air per person, water per person, and how CUBE Bunker plans two people per cube.Read the guide PlanningA bunker is not a storm shelter, and the reverseThe difference between a tornado safe room and a long-stay bunker: the FEMA P-361 and ICC 500 storm shelter standards, what they cover, and what they do not.Read the guide PlanningAdding on laterHow a modular bunker grows: removing an end cap, mating a new cube to an existing CUBE Bunker, and what to plan for on day one so you can expand later.Read the guide PlanningHow long to stay in a fallout shelterHow long to shelter from fallout: the 7:10 rule of thumb for how fast radiation drops, why the first days matter most, and how to plan supplies for the stay.Read the guide ConstructionModular steel or poured concreteModular steel and poured concrete bunkers compared: where each is built, how long the site is open, how they handle water, and when each one makes sense.Read the guide ConstructionHow deep to bury a bunkerHow deep to bury a bunker: what sets the depth, why the water table matters more than a number, and the excavation safety rules that apply at 5 and 20 feet.Read the guide DeliveryHow a 10 ft cube gets to your landWhy a 10 ft wide steel cube ships as an oversize load: the federal 102-inch width limit, state permits, signs, flags, escorts, and what to ask about freight.Read the guide SiteSite checklist before you digA site checklist for an underground bunker: utility locates through 811, soil and water table tests, crane and truck access, drainage, setbacks and permits.Read the guide SiteWhat happens on install dayWhat happens when a CUBE Bunker goes in: excavation safety, bedding, the crane set, bolting the mate packages, sealing, drainage and backfill.Read the guide SystemsHow much air a bunker needsHow much fresh air a bunker needs per person: 1 cfm in cold weather, about 40 cfm in summer heat, why passive vents fall short, and how filtration fits in.Read the guide SystemsHow much water to storeHow much water to store in a bunker: one gallon per person per day as a minimum, what that adds up to over weeks and months, and where the water comes from.Read the guide SystemsRadon in an underground bunkerWhy radon matters in a buried room, the EPA 4 pCi/L action level, how to test, and how ventilation and sealing keep radon low in an underground bunker.Read the guide SystemsOff-grid power for a bunkerHow to power a bunker off the grid: batteries, inverters, standby generators, fuel that stores well, and why lithium must not charge below freezing.Read the guide
Looking for what to pack? STYRKHOLM keeps a printable list of what to stock in a bunker besides food.