Create random sized house at will

The spell used for creation:

With this spell you create a house instant of almost random proportion. The terrain must be flat and unobscured. when the spell is cast, roll a d20.

By rolling a 1-7 you create a small sized house, big enough to shelter 2 people.

By rolling a 8-13 you create a medium sized house, big enough to shelter 8 people and 1 pet.

By rolling a 14-20 you create a large sized house, big enough for shelter 20 people and 4 pet. 

If to many people sleep in the house, the people without a bed will take a exhaustion point per night spent in the house.

A new house can be created after the old house has vanished. 

The spell used in combat:

On a successful safe, the creature does not take any damage.

On fail safe the creature takes 4d8 bludgeoning damage, is pushed back 20 feet and is knocked prone.