Tij Observatory: Eco Egg


The Tij observatory (2019) sits in the Haringvilet Dam, part of the Sceelhoek Nature reserve in The Netherlands which was opened in 2018 to help improve the biodiversity of the water and coastline there. Tij is Dutch for tide which is apt as the building sits just on the shore overlooking the water.

The reserve is a nesting area for Sandwich terns and the building is inspired by the shape of their eggs. You enter the building via a tunnel so as not to disturb the birds nesting by the shore.

View from the Water


Two Dutch firms are responsible for the design of the Observatory Ro&Ad and RAU. However Geometria Architecture from Finland was invited to design and produce the building’s marvellous wooden structure.

With experience in these types of constructions they introduced a parametric computer design to help locate the best position for the openings of the viewing deck and to provide a modular solution to the production and building of the structure.

Model of the structure

The structure itself is called a Zollinger Lamella roof, its advantage being small beam lengths much more manageable on site. Geometria had already collaborated with Ro&Ad so they knew what could be achieved together.

The Finnish team was also able to design out all the steel that had previously been part of the design including the joints which were redesigned to be wooden also. These components were made in Finland and because it was designed and made in a modular fashion it can be disassembled easily and reused or recycled. Even the tunnel that leads to the observatory is made from recycled and reclaimed materials.

The Materials chosen are appropriate for the surrounding environment the main structure is from two types of wood, Accoya wood for the lower areas where the building sometimes floods, as that wood type is resistant to the wet and pinewood above that, the cladding is of chestnut poles and reeds.

Tij Observatory from above


The Venturis would call this design a duck, from inside to out it speaks the language of the surrounding environment. It’s a testament to what a delicate imaginative and empathetic ecological design can be. Also its a great testament to Architectural collaboration fetching specialist knowledge from other practises for the good of the project. A small jewel.

  • Shape of Structure derived from an egg

  • Model of Structure

  • 3d of Structure

  • Section

  • Interior

  • From Above

  • From The Water

  • Plan showing tunnel to Observatory

Photos by Katja Effting

November 3, 2019