Chatham Towers is a lower Manhattan landmark. Designed by Kelly and Gruzen, the dynamic twin 25-story buildings are a testament to the strong architectural styles of the 1960s. Previous repair work had failed. Large patches of unmatched mortar were clearly visible and gave the towers a mottled appearance. A primary concern, for both architect and contractor, was matching both the original color and pattern. The concrete had a pronounced wood grain texture with bug holes and voids. Howard L. Zimmerman Architects specified and pre-matched the color of the Matrix, M3P, and M3P Stain to the original concrete. Quality Building Contractors skillfully replicated the subtle patterns in the primary formwork. M3P and semi-transparent M3P Stain were chosen to blend and minimize the appearance of old and new repairs. The mineral silicate coatings both added subtle color uniformity without giving the towers a painted look. In addition, M3P and M3P Stain are effective water repellents and protect the structures from water damage and carbonation.