There are several types of buildings in the game. They all have levels of structural strength, which provide defense against the creatures of the forest. When they are damaged beyond this strength, they are ruined.
Walls simply stop animals. A creature invading the village at night that runs into a wall will attack that wall and damage it, then turn around and go back into the forest. Stronger walls will stand longer and against stronger creatures.
Houses provide much less defense, but they provide storage and shelter.
Firstly, every family has a home, which is the house they sleep in. This can be changed during the day, but it must be a house on land owned by that family, or on common ground. Families who can find neither will have to survive the night outside, which is very, very dangerous. While it is possible to survive a night without shelter, chances are not very good.
Secondly, houses are where all the food harvested and wood and stone gathered is stored until it is used. Personal storage (what a family has stored in its own houses) is always used first, but if it does not contain enough material, the storage in common houses is used.
In the case of food, the most hungry peasants eat first. In the case of building materials, construction work is resolved in random order and whoever comes first gets his materials first.
When resources are gathered, they are stored in a random house of the family owning it, or if that family has no house(s) left, in a random common house. If no such is available as well, gathered resources are lost.
Every family starts with a simple hut. You can improve the hut as well as build additional houses. The benefit of additional houses is that you can survive the destruction of your first hut and continue playing. Without a house, a family has nowhere to store resources, which means no resources to build another house. This can be fixed by having common houses or a second house of your own.
Construction of houses requires a solid foundation. Laying a foundation for a house consumes no resources, but it requires one action. So building a new hut is a two-step process: Firstly, lay foundation, then on the next day, build the hut.
You can move into and live in a common house (i.e. a hut or house on common ground). Several families can share the same common house, up to 2 for a hut and up to 3 for wood or stone houses. You cannot take a plot with a house if other people are living in that house, and you cannot throw them out nor can they throw you out.
Tents are temporary emergency shelters that a family will attempt to construct if they have nowhere else to sleep. You cannot build tents as an action, they will automatically be built by your family on a random empty spot of their land. If there are no empty spots, no tent will be built.
Tents act as houses and can store resources, but they are very fragile, even the most weak animal will tear them down. If you find yourself living in a tent, you should try to build a real house as quickly as possible.
You can also build henhouses on your plots. These are small homes for chickens and every day they have a 60% chance of producing one food. However, they are easily disrupted by the creatures of the night which also find chickens tasty. If the henhouse is damaged by a creature, it stops producing food until it has been repaired.
And finally, you can put a kennel on your plots. In this dog house, you can keep one or two of man's best friends. As long as your family has at least one kennel on its grounds, you can explore the deep forest, where you really, really should not go without a dog.
As creatures attack buildings, they get damaged and can be destroyed or repaired. How much damage a building can take before being ruined can be seen in the table above in the column "Health".
Damage and repair are expressed in the same units as construction. So, for example, if a Hut has taken 3 damage, it requires 3 wood to repair it. But if a Stone Wall has taken 3 damage, it requires 3 stone to repair it.
Repair actions are always to the fully repaired value. There are no partial repairs.