Decks can be built from a variety of materials, including:

• Wood (and wood alternatives such as Trex)
• Broom-finished concrete
• Stained and/or stamped/patterned concrete
• Acrylic-finish spray deck (sometimes referred to by their brand names such as Kool-Deck or Sundek)
• Exposed aggregate
• Bricks or pavers
• Tiles (stone, ceramic, etc.)
• Flagstone or other natural stone

Your choice of deck material will probably have the single greatest impact on the overall look of your swimming area, because it covers so much surface area.