Conventillos are buildings in the Tropico 4 Megalopolis DLC. They are designed to pack as many people as possible into as little space as possible for the least money possible. Naturally, these brightly colored slums will start to fall into disrepair and decay as time goes on, their housing quality dropping every few months. For $3,500, a conventillo can be restored to its base housing quality. Their base housing quality is quite high, however, so as long as you regularly repair them, your citizens should be much happier with their housing than they normally would be.