421 West 54th Street is a six-story pre war condominium, originally constructed in 1928 and converted from a former recording studio in 2006, used by musical icons like Micheal Jackson, Madonna, John Lennon, Stevie Wonder, and U2.

Walsh Engineering preformed a targeted leak investigation with custom water testing protocols for the top level penthpuse units, followedby roof replacement, stucco repairs and installation of waterproofing systems tailored to high-exposure terrance conditions.