From problem to dream

In 1983 I founded the Architect Agency Sluijmer en van Leeuwen. Over the course of more than 30 years this Agency grew into one of the best in the region. The Agency became known for its project-based housing, educational buildings, restoration work and work for consumers. Characteristic of the work performed has always been the great attention to the architectural design, the elaboration of technical details and the use of new techniques.


Over the course of 3 decades it became clear to me how much building construction is lagging behind in its development compared to other industries. I have witnessed more and more that there is so much money being paid for the construction of badly built buildings. An example of a known issue of the contemporary building construction is that the entire chain is far too complex with end users often not playing a meaningful role and they are definitely not getting the value they expect. In addition, the current method of building is not sustainable: it is depleting the earth’s reserves.


“New houses being built poorly – surely not!”

-Hans Sluijmer, initiator-


What makes BILT unique?

BILT designs, develops and sells homes. BILT is always responsible for the buying and assembly of all parts. The process is simple and transparent because the customer has only one point of contact for the design, the purchase and the delivery of his BILT home.


The BILT building construction system is a complete alternative for building.

Traditionally, the design of the house is fixed after construction. BILT offers the possibility to continuously change the house.

The system consists of modular building panels that carry, separate, isolate and are a finished product. These panels, walls and floors are simply screwed together via an external framework.


“A BILT house can be built anywhere, can be large or small and can be up to 4 stories high”.


The interior walls are movable. This allows for any random placing of the walls that can be changed whenever required by the customer himself. The utilities of the house are located directly under the modular floor, which makes adjustments easy. This modular design allows the shape, size and design of a BILT house to be adaptable.

Making a difference

Working for BILT is just like playing sport professionally

I was 17 years old when I first participated in the Dutch Sailing Championships, the result of years of dedication, training and also processing setbacks. Sport is like running your own business. Our goal was to compete as the first “49er” in the Olympic Games in Rio de Janeiro, without any support from the Dutch Sailing Association.  After my sports career and studies I started at BILT. Entrepreneurship requires the same mentality, dealing every day with what really makes the difference.

 “From professional athlete to entrepreneur, my motivation is to make a difference “

-Bart de Haan, co-founder BILT-


As a child I played with Lego, building and changing things all the time. With Lego you know what you can do, you can make everything, the sizes are always the same and therefore you can easily adjust anything you want.

In the current building construction world it often happens that the customer experiences surprises during the construction process. I want to change this: buying a home is often the largest purchase in your life. BILT offers a high-quality alternative to building.

 “People say: it is as if I am walking in the future”


Making the impossible possible

 “Normally we do things differently, so this does not meet our standards.”

This is the reaction to our construction concept of the public sector, suppliers, building constructors and other parties – since the development of the prototypes to the construction of the first house. We had to prove time and time again to these parties that BILT is good, that it works and that it is also possible to combine so many innovations into one concept. But BILT works. And it works well.

Innovation is scary

For years I worked for high-tech companies that depend on innovation for their success. They can only win by being the first with new technologies and applications. And then I was introduced to the house building industry…

“I understand that innovation is scary”

– Coen Koop, co-founder BILT –

Innovation in building construction

Terms like ‘off grid housing’, ‘durable house’, ‘eco-house’ and the many pre-fab options make us believe that the building industry is innovating. But what’s really happening?

Building construction has the lowest innovation of all sectors. Innovation in building construction is to only change one of the components of building a home. Still our sector is the most wasteful with the scarce raw materials while building construction uses the most raw materials. If something is being built, this is the often the first and last time that the same high quality raw materials will be used. Yes, we do recycle to a certain extent, but thereafter the products are used significantly less efficiently.


Real innovation

Real innovation in the building construction industry asks for more, put aside all the knowledge and skills of a million years of building huts. Tabula rasa, and start again, with just 1 question:

 What makes sense?

Build logically without using scarce raw materials. The raw materials that you use must be fully recyclable. And why stop there? Why do we not make flexible homes? If your house is too large, then make it smaller, is your house too small, then make it larger to once again at a later stage make it smaller. Sell the parts that you no longer need to everyone who either wants to build a larger or new house.

Innovation starts with a clear idea about how it actually should be. Then you just need to let go of what you all already know. With this in mind BILT now has the first and only fully circular building construction system in the world. Innovation, innovation, and innovation.

Building is difficult

The difference between thinking and doing

I have been intrigued by the building industry from an early age. I have always been interested in how buildings are constructed and what about the construction causes them to remain standing. It was clear to me that I should therefore study engineering. My love for numbers and technical insight has meant that I have developed more and more in the constructive aspect of building construction.


When I walk through a city I almost never look at the ground floor of the buildings that I pass. I look up at the building and picture how this building was built. My girlfriend always says: “When I walk through the city with you I experience it as if for the first time.”


“Due to the fact that the executor(craftsmen or builders)on the construction site must perform things differently to how they were originally designed, once again shows us just how big the gap is between designer and executor.”

-Twan Remmits, partner BILT-


Ideas on paper in reality

When I began my studies I found out that the wide range of standard solutions leads to messy details on paper; solutions that are often changed ad hoc on the construction site. The result is therefore always different from the design that was originally conceived and intended. This shows once again how big the gap is between the developer and the builder on the construction site.


“Building construction is increasingly caught up in legal wrangling about responsibilities of own work and that of subcontractors. This is not improving the quality and is going to be at the expense of the best interests of the customer.”

Systematic details, open designs

BILT offers endless design possibilities based on standard detailing. This results in design, production, building and customizing being particularly efficient and of high quality. If different finishes are not always required, then there is also no room for interpretation errors, then you can always build houses with good finishes and therefore always the same high quality.

Each house is a prototype

As an architect I have worked for years on large international construction assignments, cutting-edge projects that always follow the latest trends and insights. It has always amazed me that these projects are often built as a single prototype; the future layout and style of a building is often difficult to modify later. This construction model delivers unusable and outdated buildings in the long term.

“With BILT I have the opportunity to build a house according to the needs and lifestyle of the inhabitants, now and in the future.”


Your own home is the largest purchase of your life and your most personal possession, and furthermore, where you will spend most of your life.  With BILT we, together with the customer, look for a design that will always suits his personal living needs and style. Because as a person and as an individual you develop, so will your life, your living needs and your tastes change. That’s why our houses are always customizable.

“The largest purchase of your life is also the most static, that’s got to change.”

-Max Brobbel, partner BILT-

If you want to start with a small dwelling which you intend to expand later, then we will create a design that grows with your life and plans. Or are you of the opinion that in the long term you would prefer a wood siding rather than one of aluminum, we can change that within two days for you.  A BILT house is not a one-time project but an ever-adaptable living environment that changes with your life.

 With BILT I have found an answer to the question I asked myself as a student of architecture:

“New buildings that are no longer suitable after a few years – that’s stupid!”