One Hyde Park in Knightsbridge is installing FlexiDry Floor Screeds that allow for a 7 day dry time. Located near luxury stores, the penthouse apartment has already sold for £100 million, making it the most expensive flat in the world. The development was built on the site of a former office building and will include 80 apartments along with amenities like spas and wine tasting facilities. Apartments have sold for record prices of £6,000 per square foot to wealthy international buyers and celebrities.