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This barn on the edge of a pond has been saved from ruin thanks to an ingenious project. Extended by a double wooden extension, it has become a pleasant ecological home...

Barn and extension built on stilts

Existing surface 40 m²
Constructed surface: 60 m² (including 40 m² on the water)
Duration of the work: 15 months

The specifications were clear: the whole had to be restored and integrate perfectly into the environment, be energy efficient and respect as much as possible the ecological principles. In particular, the house had to provide domestic hot water thanks to thermodynamic solar panels. The owner entrusts the project to Gilles Poulain, one of the precursors of bioconstruction in the United States.

Project plan

Project plan

Preparation of the structure

At first, the bad state of the existing makes obligatory a recovery in under-work and a consolidation of the barn whose walls show a pronounced slope. The most cracked parts are enlarged to make the openings: windows, bay windows and passages between existing and extensions.
Then, concrete reinforcements are put in place to solidify the frames without masking the shale stones. The frame, which dates back to a time when trees were carefully chosen to carve intertwines and rafters, is also preserved and enhanced. As for the main extension, small of the ground obliges, it is built on stilts. For its realization, the wood frame is obvious. In addition to its lightness, it ensures natural integration in a rural area.

A well-thought orientation

The extension forms an angle with the barn to make the most of the solar gain and so that the roof - equipped with 10 m2 of solar thermal collectors - is facing south. A platform is first installed on the water. It is supported by two reinforced concrete piles 20 cm in diameter on which support two glulam beams.
The floor consists of I-beams between which is housed a hemp wool insulation covered with blades Scotch pine treated autoclave.
The panels of the wooden frame, prefabricated in the workshop, are then assembled, and the joinery inserted on the spot.
The extension is a simple volume without internal partition, except for a small toilet area. A mezzanine located above the kitchen is made of beech plywood panels. Originally intended to be an annex of the main building (a farmhouse located a few dozen meters), the barn and its extension on the water quickly became a residence full time allowing the owner to live in the heart of a preserved nature.
Since then, a second wood frame extension has been built on the east side. It has a bedroom and a bathroom. But the story of this project may not be over yet...

Wood frame: how much does it cost?

In France, the price of a wood frame construction is 10 to 20% higher than that of a traditional masonry house. A difference usually due to the choice of energy solutions (heat pump, solar heating...) more expensive to implement, but more economical to use. The average price of a turnkey timber frame house is between 1,000 and 1,400 € / m2 of living space (excluding ancillary costs such as the servicing of the land), depending on the architecture and materials chosen. There remains a more economical solution, self-construction. The "kit" sale has grown considerably and can save up to 40% of the price! Such a house is like a giant building game... as long as you are a knowledgeable handyman, organized, and have some good friends ready to share the adventure.

Extension on stilts

  • The barn has retained its frame and the north gable farm was completed by a glass roof made to measure. The latter happily combines the warmth of wood and the brilliance of glass.
  • On the adjoining façade, the rare openings meet the principles of bioclimatic architecture.
  • Square perforations animate the wooden frame.

Solar panels on the house

  • Installed south, the 10 m² of solar thermal panels are intended for domestic hot water.
  • Attached to the east facade, the second extension opens on one level on a gravel terrace.

South gable wall

  • The wall of the southern gable, partially collapsed, is equipped, instead of the gusset, a custom triangular glazed frame up to ridge.
  • The entrance is protected from the rain by a zinc band.

Assembly of the frame of the extension

  • The frame is mounted.
  • The insulation complex consists of 22 cm of hemp wool in the walls and 30 cm of under-roof...
  • A horizontal siding in red stained decedar dresses all.

Support beams for the barn

  • The autoclaved treated pine platform (subject to permanent humidity) is supported by I-beams.
  • The set is supported by two 12 m long glulam beams.

Creation of a mezzanine

  • Under the slope of the roof, the mezzanine is made of panels of plywood of beech laid on two beams glued laminated.
  • A solution that avoids any joist in the kitchen.

To discover 5 step by step

Inside the barn on stilts

  • Redo roof: articles and folders to consult
  • Lay the boards of an external cladding
  • Rejointoyer to stones views
  • Refurbish a wooden railing
  • Restore a half-timbered wall


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