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Price list



Module Sizes

Basic layout solutions

Large bathroom Large bathroom
Large Kitchen Large Kitchen
Sauna and Room Sauna and Room

Additional layout solutions for modules

Plan solution for 30 and 25 sq.m. With an extra room. Plan solution for 30 and 25 sq.m. With an extra room.
Plan solution for 20 and 15 sq.m. With an extra room. Plan solution for 20 and 15 sq.m. With an extra room.

Outdoor modules

Outdoor linking module with bench Outdoor linking module with bench
Outdoor linking module with Kitchen Outdoor linking module with Kitchen


The concept is based on 10, 15, 20, 25 and 30 sq meters as well as some exterior modules. The modules are finished before delivery, just plug and play.

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Materials & construction

We focus on sustainable materials from Scandinavia.

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Lars Frank Nilsen

The ONE+ modules is developed by Add a Room in co-oporation with the Danish architect Lars Frank Nielsen.

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Come play with us! With our predefined modules and completely finished modules you are able to make your unique Add a Room house.
Plan solutions are the same for all house modules. Addtionally the 20 , 25 & 30 sq. meters have an extra room solution.

Basic sizes for a pergola and deck are:

  • deck 3,3 x 2,4 meter
  • pergola 3,3 x 1,5 meter over the deck.

Basic sizes are:

  • 3,3 x 3,0 meters
  • 3,3 x 4,5 meters
  • 3,3 x 6,0 meters
  • 3,3 x 7,5 meters
  • 3,3 x 9,0 meters

The big sliding glass doors can be placed on the short end as well as the two long ends of the house.

The house can be ordered with several options, which always are placed in the short end of the house:

  • Bathroom with toilet and shower
  • Mini bathroom with toilet and shower
  • Kitchen with stove, oven and refrigerator
  • Kitchenette with a movable stove and refrigerator
  • Bunk beds
  • Wardrobes
  • Sauna

Outdoor linking module
Create outdoor rooms and link together more rooms, by using our smaller modules.

The outdoor modules provide, together with the pergola, a nice feeling of being inside while you are outside. The outdoor modules (3,3 x 1 meters) consist of a deck, pergola and a thick wall.

The outdoor linking module options are:

  • Outdoor kitchen with gas stove, a sink and a small cabin on the back. All are integrated into the wall
  • Outdoor bench and a small cabin on the back. All are integrated into the wall
  • Additionally both the above can be ordered with a outdoor shower on the backside
  • And both can also be ordered without the standard deck, 3,3 x 1 meters if for example you already have a veranda to put it on

Sauna house

The sauna house has multiple purposes. The sauna module is also 10 sq.meter (3 x 3,3 meters) and it is possible to connect to other ONE+ modules. Use it as a sauna or as an extra room.

Another alternative is to put it on pontoons and use it as a sauna raft instead.

The sauna house has two doors and two decks, one at the front and one at the back. The back veranda is thought of as more private for taking a swim or an outdoor shower.

The deck goes through the sauna and is in total 3 x 6,7 meters.

Material & Construction

We focus on sustainable materials from Scandinavia.

  • ONE+ is insulated.
  • Insulation depends on location and use.
  • Can be ordered for summerhouse or permanent house.
  • Electricity ready within the house.
  • Dark kernel pine floors indoor and Superwood veranda floor on the outside.
  • The wainscoting has a characteristic thin profile designed by AART. The wainscoting is named Superwood and is sustainable and environmental friendly. The house is either black or in natural wood, last mentioned gets a grey patina over the years, and is possible to stay unpainted due to the fact that Superwood is high pressure impregnated.
  • The walls inside are white painted or birch veneer.
  • Energy efficient sustainable windows from Velfac, with slim frame, outside aluminium and inside wood profile. The slim frame of VELFAC windows let in significantly more natural daylight into the room.
  • The roof is welded and has a slope on 1,5 degree.
  • Heating system. E.g. small electrical heating (2000 watt) is enough for a ONE+ house and can easily be placed due to several plugs. Floor heating is available in the ONE+ bathrooms. Wood stove, air source heat pump and sun panel can also be provided.

ONE+ is build at our indoor production site in Scandinavia by carpenters with many years of experience at our partners Hansen & Larsen. ONE+ house is delivered in one piece and has hooks in the roof to ease the lifting and moving of the house.

The house is placed by a crane on a point foundation or a rand foundation which have been prepared in advance.

The combination of the architecture, sustainable materials and high construction quality reduces maintenance and ensures a house for generations.

Please have a look at the images.

Lars Frank Nilsen

Lars Frank Nielsen is one of the founders of the Danish architect company 3xN, known for the Danish embassy in Berlin and several significant buildings in Denmark and around the world. After many years working at 3xN he decided to focus on designing smaller buildings. His company ONEN primarily designs different products such as benches, door handles and furniture. He has a focus on functional, minimalistic and sustainable solutions. Add a Room developed the ONE+ system in collaboration with the Lars Frank Nielsen.

Lars Frank Nielsen explains:

“The project started as a refinement of the minihouse concept in Sweden. We, Add a Room and I, wanted to provide a design alternative to the existing mini houses in Sweden called friggebod that mostly look like play houses for children. Our goal was to design a simple, almost minimalistic house, a house that can stand alone, but also a house that can be pieced together unit by unit. During the design process, there has been an evolution towards a true “multi-unit-concept”: you can start with a single unit and enlarge it step by step into a genuine holiday home.”

Lars Frank Nilsen