My cousin built this AMAZING Harry Potter house in 8 months from scratch, 80% of it from recycled and repurposed materials–Pringles containers, cardboard boxes, tissue paper, packing materials, small plastic tips off nasal spray. Many of these items he found in his own recycling bin, some out on the curb that folks had put out with the trash.
The roof on the great hall was created from used file folders. “It made the perfect roof.”
He said the biggest part was molding each tiny block in plaster in a silicon mold and waiting for it to cure.