Walls can be finished with various materials like paint, wallpaper, cladding, and panelling. Paint preparation involves ensuring the wall is cured, applying putty and primer before painting. Wallpapers are available in various materials like vinyl, fabric, wood chip and have advantages like decorating options but need regular maintenance. Cladding materials include wood, concrete, brick, stone, glass, tiles, boards and metal which are installed on walls for decorative and protective purposes. Panelling involves covering walls with materials like wood, MDF or laminates for insulation and decorative purposes.