The project involves providing structural design and material specifications for constructing an A-shaped house with a balcony. The dimensions of the house are 12 meters by 8 meters with a ground and first floor, the total height of house is 10 meters. The walls are constructed with steel and sandwich panels. The design should include the footing and tie beam (if required). Additionally, please provide the cost of: 1. interior design 2. the quantity of materials required.