For example, if a base has 10 buildings plus the main building, each building destroyed takes away 7% of the main building's original total health. The only exception is when there are 3 or fewer buildings on the base besides the main building. In this situation, the damage that each building deals to the main building is capped at 20%. For example, if a base has 3 buildings plus the main building and those 3 buildings are destroyed, the main building will have 40% of its health left.. Calculators Army Statistics Calculator Headquarters Rush Calculator Event Loot Calculator Headquarters Damage Calculator. Find out how much damage destroying buildings deals to a Boom Beach base's Headquarters or Power Core.