By partially embedding the new children’s bunkroom into the sandy slope, this cedar shingled addition doubles the size of this small 1930’s seaside cottage without overwhelming the scale of the original structure. The original low ceilings were reengineered to make the most of the low volumes, reconfigured for living and outdoor dining. The new dining room and kitchen gently rise behind the original house’s profile, allowing dramatic views from within; while from the water side, the building appears unchanged. At the new entry, a transparent vestibule makes Wellfleet’s Mayo Beach the focus of one’s approach.