Kate Watson-Smyth is a writer, journalist, blogger and consultant specializing in interior design. This is the back of her townhouse in London. After she added this extension and deck, she didn't love the look. So, she replaced the deck with cobblestones and painted the structure this glorious soft black with blue undertones color, called "Railings" by Farrow and Ball. Read more via Kate's Instagram post (first link below) and find her blog via the second link below. The third link is to the Farrow & Ball website.