Slangen + Koenis Architects (S+K) is an architecture firm that consists of a permanent team of 25 employees, this team contains a healthy mix of experience and young design talent. The company was founded in 1985 and has over 30 years of experience.

Chemistry and innovation
Our special attention goes towards a certain chemistry in the relation with our client. The aspiration is to establish a high degree of trust, in which the client feels free and confident to leave it in the hands of the architect, after which the architect will fully live up to the expectations. It is our strong belief that every good project needs a good and above all involved client, as an architect you can influence this directly. Every project provides, within a certain framework, the opportunity to create architecture as long as your focus as a company is aimed on this aspect. If you are always willing, as a team to familiarize yourself with the required knowledge at the beginning of a process, you can open-mindedly take this challenge head on. It is our vision that this mentality will result in innovative and unique results in each project.

Our goal is to work with enthusiastic clients and users every day. We want to make extraordinary projects for a realistic budget and we want to add something special, something ours, to every single project. The well-balanced process to create a good building in harmony is for us just as important as the building itself.

Through the years S+K has become a specialist in the field of public facilities, swimming pools and sports accommodations in particular. Over time the company has gained detailed knowledge and experience in our field, especially regarding swimming pools, sports centres, fitness centres and leisure- and cultural centres, often as a clustered concept. Our client base consist mostly of municipalities and educational institutions. We are specialised in integrated design and are often commissioned on this basis. In addition to the architectural design we are often also responsible for the structural design, technical installations and acoustics and fire safety. This gives the client the advantage having a single point of contact. The most projects are so called complete assignments and include all stages, from concept design to realisation.

S+K performs all tasks with our own team. 3D-images and models are produced in house and our own project managers are be devoted to the overall coordination and building supervision. We produce all the presentation material that will be provided to the client and we can implement these visualisation methods on behalf of every design process.

Dimension of projects
Our reference projects give a clear image about the differing scales of projects that S+K commonly has in its portfolio. In addition to large scale developments we are also involved in a number medium sized and smaller projects, including renovations and expansions. These projects are often just as challenging and inspiring as the bigger projects, both in design and process.

It is our vision is that the most sustainable building is one in which the “inhabitants” feel great and which adds value to its location. We think that this can be created if the building is:

  • welcoming and brings people together
  • flexible and has the ability to transform based on the needs of each user;
  • responsible in its energy and water consumption;
  • materialised using honest materials;
  • ages in a charming manner;
  • comfortable in its use;
  • feels as THEIR building!

It is our greatest ambition to realise this for each of our designs. We all strive for an overall concept in which all these elements reinforce each other. Our love for sustainable materials, smart installation concept and our constant drive to innovate our the force behind this quest. Sustainability in both concept and realization is embedded in the genes of our team!


Trainee m/f
Are you the enthusiastic, motivated, flexible and stress-resistant trainee that we are looking for?

Then please send your CV and a short portfolio (pdf) to, so we can invite you for a meeting. For more information please contact Iris Koning via (030) 688 80 44.

Sustainable design

Designing and building with a strong focus on the entire life cycle of a building forces you to make long term decisions. If all parties involved share this vision the entire process of design and realisation becomes more harmonious. Placing the greater good above individual interests and listening to each other’s point of view can lead to surprising decisions.

Building volume, orientation and building systematics form, in our vision, a strong basis for a sustainable and operations orientated design. By looking for a optimized volume we can reduce the energy use more than with the use of special technologies. This volume also form the basis for a low maintenance building. The right orientation optimizes the use of daylight in keeps out the warmth of sun. Introducing a logistical system with a clear routing and clear sight lines makes a sports accommodation save and easy to operate. A high level of transparency reduces the risk of vandalism and maintenance. Building that are easy to clean are maintained with greater pleasure and age better. We always aim to choose the most sustainable materials. The use of wood, steel and concrete ensure a low environmental impact and the possibility to recycle.

A smart building system minimizes the building time and thus saves money. Using a smart building system, maximising the use of prefab elements, also facilitates a sustainable and high quality materialization without unnecessary layers; we make more with less! In addition the building needs to have great atmosphere to dwell and exercise. Acoustics, air quality day light and interior materials play an essential role in creating this atmosphere.



For more detailed information about our office and for a complete overview of our projects it is possible to request our portfolio via the following adres.

Slangen + Koenis – Architecten
Swammerdamweg 11
3401 MP IJsselstein
t +31 (0)30 6888044
f +31 (0)30 6886974

KvK Utrecht: 30074297

Privacy statement


Trainee m/f….


Through the years S+K has become a specialist in the field of public buildings and swimming pools and sports facilities in particular….

Sustainable design

Sustainable design is one of the core values of our company….


Slangen + Koenis Architects (S+K) is an architecture company that consists of a permanent team of about 25 employees….


Slangen+Koenis maintains valuable and innovative relations with the following parties….

Sports complex de Wedert will be festively opened today. The transformation included a thorough renovation of the indoor and outdoor pool and the addition of a sports hall, café and health centre. The new complex has become a new heart for Sports park Den Dries and ready for a sportive future.

At the start of the summer we submitted the application for the building permit for the sports complex in Zaltbommel. Before the end of the year we will send out the public tender, so we can start the construction in the first quarter of 2020. We intend to be able to take our first dive in the summer of 2021! For more information visit our projects page.

6 months ago the project won the Noordwijk Innovatieprijs Zwembaden 2018 for its unique financing strategy. Last Monday the start of realization phase was marked by revealing the construction sign and the name of the new swimming pool. The residents of the municipality Rheden and surroundings will be able to enjoy the warm and natural atmosphere of the Biljoenbad from the fall of 2020. Read more about the project here.

The construction of new sports hall for the Sint-Maartenscollege and Gymnasium Novum in Voorburg has started and will be completed by the end of 2019. The beautiful and green character and the shapes of existing elements of the surrounding park has inspired our team  to create an open and inviting and sustainable pavilion that complements the atmosphere of the park. Read more about the project…

Earlier this week the municipality of Middelkerke announced that the VITA Groep has won the DBFMO tender for a new swimming pool in the Flemish coastal town, based on our design. The program includes a 25m competition pool, an instruction pool and recreational pool, wellness, restaurant and the option to add a sports hall in a later stage.

Our design was praised for its compact volume, optimal integration in the dune landscape, added value to the public space and the choice of materials and fresh colours. The functionality, integrated sustainability concept and accessibility are also seen as an added value. We are looking forward to detailing the design and together with our partners realize a beautiful swimming pool for the inhabitants and visitors of Middelkerke. Investment in the complex is approx. 20 million euro ex. VAT and VITA Groep will operate the complex for 30 years.