Flexible and affordable

One Planet has developed a robust, demountable high-quality prefab apartment with bathroom and kitchen that allows vacant buildings to be filled quickly and easily with small living units between 18-60 m2. A unit can be installed in one day. This product, as well as all rights thereto, plus our coalition of partner suppliers, was taken over from One Planet at the end of January 2020 by the company Bouwbedrijf Huurdeman B.V.  in Amersfoort.  https://www.huurdeman.nl   Huurdeman has built a new showroom in their own building and now offers FlexApartments in  the market on a commercial basis.

For people with small budgets

  1. Care clients
  2. Students
  3. Refugees
  4. Single parents
  5. Young starters
  6. Retired people

Innovative and sustainable!

The FlexAppartement fits under the existing office ceiling and requires no holes in the floor and only tiny adjustments to the building. It can be installed in one day by two professional workers, including bathroom and kitchen. The modular components are supplied as a flat-pack kit with pre-engineered components, like an IKEA package. The FlexAppartement uses a vacuum wastewater system, like in an aircraft, which saves water and makes the positioning of the FlexApartments very flexible. The walls and ceilings slot together and are made of robust sandwich panels and click together. The building is digitally measured-up beforehand and all parts are pre-built in the factory ready for quick assembly on-site.

The solution to two problems

  1. Empty buildings; In some business areas like De Hoef in Amersfoort, 40% of all office spaces are empty, some longer than 10 years. These buildings have become redundant because people can now work anywhere online. Much of this empty real estate is owned by pension funds and institutional investors, whose managers inflate their balance sheets by giving their real-estate portfolios an artificially high book value based on old or partial office rentals. There are various ways of making a building appear more valuable op paper than it really is, like kick-backs and incentive-periods which are not reflected in the lease contracts. This creates a property bubble that investors and banks prefer to keep hidden. For artificial fiscal reasons many buildings therefore stay empty. If they were rented out for housing at a lower price, the fund managers would have to devalue the buildings to a real market value. The people who pay the price of empty buildings are not the fund managers themselves, but all the pensioners at home whose receive less money each month than they are entitled to, if these buildings were filled with small dwellings. The municipality supports the property bubble by allowing developers to build new houses on virgin ground, instead of requiring them first to redevelop all the empty office buildings for apartments.
  2. Shortage of low-budget housing; Amersfoort has a waiting list of more than 12,000 people - students, refugees, care clients, singles, starters etc, looking for cheaper housing. Many people do not have the fixed jobs and stable income that banks require for a mortgage and will never be able to buy a traditional house or apartment. A new solution is needed – One Planet FlexApartments!


A coalition of strong partners, with One Planet in the lead for marketing, sales and project-engineering and the other partners for the supply of pre-built parts. In the meantime, the building company Huurdeman in Amersfoort has taken over the role of One Planet.

Paul Heistein

Dick Hoogendoorn

Auke de Vor

Ton Vollebregt

Rob Besemer

Harold Arts

Ed Standaart

John Vranken

Old contact ...... -> ...... New contact

paul.heistein@oneplanet.org               I.dewolf@huurdeman.nl
tel. 06-52401947                                  tel. 06-15290369

Our first test-unit, built in 1 day with 2 workers! Here is a 360-view 2017-07-27 10.03.24 

Transformation plan for your building

FlexApartments lets you transform your building into small homes for people with small budgets - students, care-clients, starters, single parents, divorcees, social urgencies, retirees and so on.

Advantages of a vacuum system

The toilet, sink, shower and kitchen water is sucked away through a 50 mm polypropylene tube with a powerful vacuum of minus 0.5 bar. We use the technology of the Norwegian company Jets. Their highly reliable systems are used in over 60,000 applications, including cruise ships, major stadiums, various size buildings, trains, festivals such as Lowlands and so on.

Advantages: (click on the image)

  • No holes in the floor or ceiling of the building; no demolition work; the apartments can be placed anywhere, very flexible
  • Environmental benefits; 1 liter of water per toilet flush instead of 6-7 liters
  • The whole building and all apartments are serviced by one 50 mm vacuum pipeline. The pump can be placed up to 200 m further away and the output is very suitable for producing biogas
  • The vacuum system is very robust, strong and reliable (their use in aircraft and cruise ships demonstrates this)
  • Air from the toilet is sucked away, similar to airplane toilets. The toilet has its own inbuilt ventilation system.

Plug-&-Play bathroom-kitchen

The bathroom and kitchen are supplied in two ready-to-use prefab modules, each on a pallet. Each unit can be installed by two people in about one hour. The water, vacuum, electrical and ventilation lines are connected via couplings to the "umbilical cord" in the hallway. Shown below is a compact 'wet cell' for a student housing project. (click image)

High-quality sandwich-panels for the walls, roof and doors

You can choose from different panels depending on your needs. For example, wood-and-cork, or MDF-and-mineral wool. All with fire and sound certification. We first measure-up your building with a digital laser, then we make a 3D model of all homes including bathroom kitchens and pipelines. At the factory, the 'IKEA packages' are tailored-made for your building so that each Apartment package fits exactly. On-site, you can then quickly and efficiently assemble it like a LEGO box. With this type of custom-prefab you get a better product at a lower price. You save a lot of work at the project location and can significantly reduce the project duration. (click on pictures)


Sell and deliver FlexApartments in custom-built prefab flat-pack 'IKEA kits' that allow tenants and owners to fill their vacant buildings with with small modular homes, in a flexible, efficient and affordable manner. The residents can if wished, under supervision build their own apartments. A professional company will lay the central services and connect them to each apartment via an 'umbilical chord.'

Project status

One Planet built its first prototype apartment of 18 m2 in 2016 - see Kit House. Then we built a second show-model of 27 m2 in Amersfoort in 2017. See the pictures below. This second model uses a simpler design and a unique new vacuum sewage system. Now we can offer FlexApartments commercially with a coalition of four strong partners. Here below is the construction of our second model in one day with two workers! In the meantime, the building company Huurdeman has built a 'third generation' unit aan now offers this for commercial projects.


Download: Flex Apartments Brochure

If your building has a high ceiling, you can place a sleeping platform above the bathroom-kitchen unit, with additional furniture modules around it. Click on the picture to enlarge.

Here is a birds-eye view of a FlexApartment

Here you see the panel assembly - one apartment in one day with two workers!

Each home has its own separate, insulated sandwich panel wall, with extra mineral wool between the houses. So no sound transfer between homes, and a high fire resistance. 

This shows the ONLY adjustment in the existing building = 1 hole diameter 80 mm in the wall for the 50 mm vacuum line plus 20 mm for the water supply.