Overlapping House is located in Nakhonratchasima, Thailand, close to Khao Yai National Park, the 3rd largest park in Thailand with 300 kilo square meters. The area is famous for tropical seasonal forests and grasslands. This 1,351 sqm. vacation house is designed to be a weekend getaway for the house owner, Yuwalee Leenutapong and her family. It consists of 8 bedrooms, common area of living-dining-pantry, an onsen, and big balconies and outdoor terraces including the rooftop that overlooks the beautiful mountains. Inspired from the contour at the hillside site, the architect from Vaslab Architecture designs the floor levels and the mass-form of the house to overlap each other creating a number of different recreational spaces throughout the house. As the house sits on the top of the hill, the architect takes the design advantage to have its front façade facing north to see the best of the panoramic mountain views, which makes all the 8 bedrooms and the ground floor common space sharing the same views. The house main axis runs along the site contour in east-west direction and it gets also the good natural ventilation from the southwest. As seen from the exterior, one can see the two deviated masses interlock and overlap with each other. The overlapping characteristic of these 1st and 2nd levels creates a number of different shaded and sunny areas that are used for recreational spaces including the front all-day shaded terrace that can look out to see the mountain lines and the BBQ terrace that sits on the lower level. The house structure is post-beam reinforced concrete system with the mat foundation for the footing as the house is located on the rock mountain. The exterior finishes are bare-concrete and local mountain stones, designed to be harmonious with the site context. Teak wood is used to soften the masculine façade and it also continues outside-in to the interior spaces. Not only that the deviated axis defines the exterior house form, the interior space and its functions are also defined by this deviated axis. For all the rooms and spaces are not in the symmetrical shapes, as seen in other general houses, that makes the function arrangement of the spaces quite challenging and more interesting. For the house interior, PHTAA Living Design, takes this challenging point and then designs the open-plan for the first floor common area where all the divided functional spaces are all connected in the big living space with no walls but each has its own boundary.