Waterproof properties of silicones. Two household items that use the waterproofing properties of silicones: waterproof plasters (left) and furniture polish (right). Water droplets are seen on the plasters in the packaging artwork, and on the furniture polish (in the tin and on a cloth). Silicones are oil-like polymers of silicon and oxygen. They are hydrophobic, repelling water molecules, allowing them to be used as lubricants, sealants and to waterproof objects.