Introduction | The Water House

A leading and internationally acclaimed Architectural, Planning and Engineering firm based in Tokyo, Japan, since 1970 is quite a dull introduction for an architectural firm Like Nikken Sekkei Architects, which provides such innovative and advanced design solutions. On the Water House is one of their exemplary statement projects in the Residential Architecture category.

The Water House by Nikken Sekkei - Sheet1
On the Water house_©Nacasa & Partners

It has a site area of 1325 sq.m. and is located on the lakeshore of Lake Chuzenji in Nikko city. On the Water House is a private summer guesthouse replacing the five-storied corporate retreat facility. This 7.3m high residence by Nikken Sekkei is located on a sloping site with a contour interval of 7m from the road down to the lakeside. The site sits within quite splendid natural settings like Lake Chuzenji and Mount Nantai and the forest of autumn trees.

The Water House by Nikken Sekkei - Sheet2
Site_©Nikken Sekkei Architects


The site is located in such a natural setting that context becomes the foci of idealisation. Located on the lakefront provides an opportunity for Varied vistas. Nikken Sekkei has envisioned this guesthouse as a continuously flowing space in a spiral manner resulting in diverse lakefront environments starting from an entrance towards bedroom spaces. These environments, varying according to the physical distance from the lake water surface, include elements like the sound of ripples, reflecting light from surface water, humidity and thermal radiation.

The idea was to make a space that interacts with its surroundings and blends into it. The space must be subtle and minimal yet exquisite and luxe in functioning. 

The Water House by Nikken Sekkei - Sheet3
Sequential diagram_©Nikken Sekkei Architects

Design in making | The Water House

The guesthouse is a double-storied project, approached from the 2nd floor from the roadside. The entrance area opens into a welcoming dining space on the 2nd floor, forwarding the spiral movement with the scenery of the lake and ending into guest bedroom spaces at the 1st-floor level.

The Water House by Nikken Sekkei - Sheet4
Floor plans_©Nikken Sekkei Architects

The lake water is brought in towards the inner garden by removing the shoreline protection work that existed with the previous retreat facility. The scenic view is framed with a huge, 20m spanned floor slab extending over garden space.

Cantilevered Roof_©Nacasa & Partners

Design elements

The project caters to its surrounding context by providing a non-homogeneous environment in a mild climate. Different spaces have a variety of thermal settings, such as the fireplace warmth and the dryness of the air. Since the interconnected and overlapping interiors & different elevations of the space, the interior and the central spiral circulation guide one into moving forward while experiencing and finding the comfortable space around the house. 

Materials, Construction & Technology

The material palette mainly including of exposed concrete as the main exterior finish and zinc galvanised stainless steel sheet for roofing. The interiors include wood, Bush-hammered finished stone & concrete as flooring and plaster, melted metal spray &  wooden board cladding as finishes for walls. Nikken Sekkei Architects have designed the ceiling as a very minimal element, for which it is finished with plastering. The structural system is mainly Reinforced concrete. The material palette reflects subtle tones of colour, which balance the surrounding context’s colour palette, which varies around different seasons.

The Water House by Nikken Sekkei - Sheet6
Materials_© Gankosha, Harunori Noda

The porch opening into the dining room is sheltered with a cantilevered steel frame roof. The major structural integration for the roof is to design it such that the designed loads are in equilibrium with the snow load. The roof is 1.2m deep, considering the snowfall; the steel beam of its roof is pre-cambered, and sag rods are provided at 3m intervals at the roof tip for additional tension to the roof. The structural design is to be used to prevent heavy snowfall loads. The reactive loads from sag rods taken from the reversed beam of Steel reinforced concrete is used to create the eaves of the soffit on the 1st floor, which are seen as straight and flat; hence they reduce the deflection of the long spanned slab. By balancing the deflection of the roof to withstand the snow load, the opportunity of utilising large-scale sashless glazing becomes feasible, resulting in having maximum sights of scenic panoramas.

Roof Diagram & Detailed Section_© Nikken Sekkei Architects
Roof Diagram & Detailed Section_© Nikken Sekkei Architects

Nikken Sekkei Architects have used BIM mode to study the contextual topography to locate the ideal site. This innovative technology of BIM, a.k.a. Building Information Modelling, is key to understanding the requisite scale of an individual room, including its opening proportions, the visual sequences and movement space into the building. Making and analysing projects with BIM explains the clarity of structural integrity, natural ventilation and humidity and thermal comfort levels within the building by defining the finishing materials and fireplace & furniture locations. 

BIM model analysing thermal comfort & natural ventilation_© Nikken Sekkei Architects
BIM model analysing thermal comfort & natural ventilation_© Nikken Sekkei Architects

Epilogue | The Water House

Nikken Sekkei Architects have expertise in innovative technology and seamless designs that can impact modern architecture. And On the Water House perfectly reflects upon their values of such a modern contemporary retreat with subtle luxury of spaces and experience in and around the space. On the Water house is one of the steps to Nikken Sekkei Architects’ aim to lead the world towards a new future.


Kelawala, V.K. (2015) On the water: Residential: Projects, NIKKEN SEKKEI LTD. Available at: (Accessed: December 16, 2022).

Kelawala, V.K. (2022) Nikken Sekkei, Wikipedia. Wikimedia Foundation. Available at: (Accessed: December 16, 2022). 

Kelawala, V.K. (2015) On the water: Nikken sekkei ltd, Archello. Available at: (Accessed: December 13, 2022). 

Kelawala, V.K. (2020) On the water house / nikken sekkei, ArchDaily. ArchDaily. Available at: (Accessed: December 18, 2022).


Vishwa is an architect and research & heritage enthusiast. Driven by culture and art, she is passionate about creating designs that reflect persona and promotes well-being & sustainability. She, being keenly observant; believes that the god is in detail.