De Warren

Housing cooperation De Warren has been developing an ultra-collective apartment building since 2016, located on the new Centrum Eiland in IJburg, Amsterdam. The building will be made of biobased materials and is drawn up from cross laminated timber and recycled wooden finishes. Its circular timber facade is completely made from reclaimed hardwood bollards. In order to saw the large bollards into individual facade elements, creates a puzzle that is difficult to solve manually. Summum Engineering has developed a parametric model with linear programming algorithms to solve this problem in a matter of minutes.

De Warren is a building that connects people, encourages interactions, welcomes animals, and is sustainably built. It consists of 36 apartments from small studios to family homes, all combined through communal spaces that make up 30% of the building. These include co-working areas, a yoga and workshop space, a silent room, a makerspace, a music studio, communal garden, greenhouse and roof terrace, and, at every level, a common kitchen. At ground level, a collective living area acts an atrium, with views all the way to the top, as a sort of timber cathedral, tying the whole building together.

Reclaimed facade

Together with the contractor, the ambition has been to reduce the impact of the building, and use as much circular building materials as possible. The use of timber fits well within this philosophy, as a renewable material with a negative climate impact due to carbon storage. The facade structure and cladding have been the primary candidates for using reclaimed timber. The structural components of the facade are made from reclaimed bollards or mooring posts, which are typically made from hardwoods such as Azobe and Basralocus.

Parametric solutions

A challenge is to saw the large bollards into individual elements of the facade. In essence, one needs to match the supply of elements with a given size with the demand created in the building’s design and dimensions. The supply is whatever sawmills, material hubs and demolition companies have available. The demand is that developed by De Warren, designed by the architects, Natrufied Architecture, and dimensioned by the structural engineers, in this case Pieters Bouwtechniek. In order to tackle this challenge, Summum Engineering created a parametric model. The modelling involves a complex mathematical puzzle, also known as a ‘linear programming problem’ that require specific algorithms to solve. Once the model was designed and programmed, it provided immediate insight into the required volume and size of bollards, after information from suppliers and the architect was combined. Then, the algorithm computes an efficient manner in which each vertical and horizontal facade element can be sawn from each available hardwood bollard. It does so while taking into account cutting losses, reducing material waste and calculating a cost estimate based on cost numbers from the suppliers and sawmills. Then, a document is generated with a sawing list, showing per bollard, which facade elements have to be sawn from it, including a visual aid. The parametric model allows the number of required bollards to be limited, while maximizing their use. This information was used to get more specific estimates, before settling on a final sawing schedule.

A second life

It has been extremely important for De Warren to coordinate between the contractor, suppliers, architect and structural engineer, in order to achieve this complex novelty: a completely circular facade with elements of varying dimension. The sawing of reclaimed bollards doesn’t always go as planned: some have cracks, tapering sections, holes and defects, and so on. This creates a difficult process require a lot of time, but offering something valuable in return. By using the wealth of knowledge and experience of demolition companies, sawmills and timber specialists, and embedding this in a parametric model, it has been possible to offer as much timber as possible a second life.



De Warren | Just Dengerink

Natrufied Architecture | Anja Verdonk

Facade optimization
Diederik Veenendaal | Summum Engineering

The work by Summum Engineering was funded by the Province of South Holland and De Warren.

Location: Amsterdam, Netherlands
Time: 2021-2022
Status: Under construction

Services: Optimization algorithms, parametric modelling


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