All of the available mushroom houses can accommodate up to three Smurfs. Once a house has been build a new Smurf will come back from the forest and enter the village to live there.
Taping on the house opens a window on the right-hand side of the display, at the bottom of that is an upgrade button (only available from level 9 onwards after Handy Smurf’s Mushroom house has been build).
The first upgrade costs 500 Coins and visually adds doorsteps to the house and now two Smurfs can live in it.
A third upgrade adds another Smurf to the village, this one is available for 4 Smurfberries and hence the maximum number of Smurfs being able to live in a house is three. This upgrade adds an attic and a laundry line to the mushroom house.
If more Smurfs are needed there is also an option in the Smurfberry-Shop to buy a new Smurf for 5 Smurfberries without the need to provide him with lodgings.