Expandable surfaces made from sheet materials with slits distributed on the surface of sheet material where the surfaces expand by application of force along or/and across the surface of sheet material. The unexpanded surfaces are flat sheets, or closed surfaces like cylinders, spheres, tubes, or custom-designed organic shapes marked with pre-formed or post-formed slit designs. The expanded surfaces can be single units or modules which can be attached to one another through various means. The sheet materials range from hard surfaces like metals, to softer materials like papers and plastics, or pliable materials like fabrics, rubbers, synthetic surfaces or bio-surfaces. The slits are arranged in patterns ranging from periodic, non-periodic to irregular designs. The slits can be straight, bent, curved or irregularly shaped with even or uneven spacing. Slitting can be achieved by digital cutting or punching devices like laser-cutting, water-jet cutting, digital punching, automated dies, etc. or pre-formed when casting the sheet material. Force can be applied manually with tools or through the use of machines and special set-ups. Applications range from architectural surfaces, walls, ceilings, panel systems, structures and sculpture. On a smaller scale, applications include containers, packaging material, fabrics and human wear. On micro- to nano-scale, applications range from expandable surfaces for gauzes, band-aids, stent designs, skin grafts, semi-permeable membranes and micro-filters for various industries including purification of fluids and chemical substances.