Picture of Make a house shape from cardboard
This part is where I got a little ambitious. I cut strips of cardboard about 15 cm wide to create the walls of the mold and hot-glued them around the house’s base shape. Don’t worry about perfection—cement is forgiving—but make sure everything’s sealed, or you’ll have leaks. For the windows, I used foam blocks and a toilet paper roll for the round one. Just stuff the foam inside the cardboard cutouts. A tip: brace the outside of the mold with extra cardboard pieces to prevent the walls from bowing when you pour in the cement.
