

They will only return to your pool of available population if you sell that building. Your total population stays the same, but those people are now working in your new factory/barracks/store/whatever.

When you build one of those buildings, your available population goes down (you can see in the building menu how many people a building requires). Many other buildings (production buildings, goods buildings, military buildings) need a certain number of people to function (think of these as workers required to keep those buildings running). If you only build buildings that proide population (a city completely filled with houses, for example), your available population is equal to your total population. Unless you build new buildings that add population or remove existing ones (or level up a Great Building that provides population) your total population will not change. Many of those provide you with a grab bag of FPs, goods, medals, attack bonuses etc., and a lot of them also add population. There are also a few Great Buildings (like the already mentioned Tower of Babel) that add to your total population (in those cases the Great Buildings adds more population the higher its level is) You can aso get special buildings from events (and from Guild Expedition, the Antiques Dealer or Cultural settlements). Early on in the game that will mainly be houses, you can see how much population a given house adds in the building menu. Any residential buildng adds to your total population. So, basically you have a total population number and an available population number. I'm think you may have a few not quite right ideas about how population works in FoE (mainly because you use words like replenish for available population, which doesn't really make sense in FoE)
