Rehabilitation of a barn in a Third Place

by jean-marc Pitet
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2022-05-25 00:00:00
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France
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345 / FR

Heritage renovation

Building Type : Other building
Construction Year : 1880
Delivery year : 2021
Address 1 - street : 20 Boulevard Lyautey 91490 MILLY-LA-FORET, France
Climate zone : [Cfb] Marine Mild Winter, warm summer, no dry season.

Net Floor Area : 185 m² SHON
Construction/refurbishment cost : 525 000 €
Cost/m2 : 2837.84 €/m²

Primary energy need :
80 kWhep/m².an
(Calculation method : RT existant )

Energy consumption

Economical buildingBuilding

< 50A

51 à 90B

91 à 150C

151 à 230D

231 à 330E

331 à 450F

> 450G

Energy-intensive building

The project is located in the heart of Milly-la-Forêt, on the plot of an old farm transformed into the Maison du Parc naturel régional du Gâtinais francais. The barn is positioned in a constraining situation: adjacent to the separating limits, mainly oriented to the north and surrounded by different levels of base.

The project proposes a rehabilitation and an extension of the barn by preserving the characteristics of the rural architecture of the French Gâtinais. The construction favors the use of bio-sourced materials and the extension is treated in a contemporary way by taking inspiration from the characteristic elements of the vernacular architecture, in particular the beehives and dryers. The project is presented as follows:

Three levels are organized in the barn for its activities with a low first floor in half level and an interior structure in wood. The north facade is modified: the barn's carriage door is replaced by a wooden glazed frame and a large horizontal bay is created under the eaves of the roof. The existing roof is preserved, only pierced by flush roof windows on the southern slope.
An extension is created on the west façade to accommodate a meeting room. This cantilevered extension signals the commitment of the French Gâtinais Regional Nature Park to sustainable and biosourced architecture. It presents a volume with a double slope roof at the R+2 level, suspended from the existing gable. It consists of a wood frame, a roof of wood shingles, wood cladding, interior insulation in plant fibers and wood joinery high performance protected by external blinds. A horizontal bay is created under the extension to light individual offices; it accompanies and emphasizes the extension of the cantilevered structure.

The project combines modern techniques with traditional know-how :

The stone masonry and lime renderings are preserved. The interior wall finishes are also made of lime plaster.
The use of hemp concrete on old masonry ensures a very good thermal comfort while promoting local know-how and short channels.
The existing framework is preserved and the new frame is designed around the existing trusses. Entirely modeled in 3D, the framework was digitally shaped and assembled in one month.
A flexible rainwater collection tank is integrated into the lower level for sanitary purposes.
Electric vehicle charging stations are located under the extension.
The Cep energy performance objective is set at 80 kWhep/m².year. The summer/winter comfort levels are optimized (inertia, cold wall sensation, phase shift...).
The furniture is made from reused wood by an integration company.

All of these recommendations contribute to limiting the ecological footprint of the construction, to thermal comfort and to the qualitative atmosphere of the project.

Photo credit

abdpa / Daniele Rocco

Contractor

Name : Parc Naturel Régional du Gâtinais français

Contact : Cathy Bos - Chargée de mission Architecture et Paysage - 01 64 98 23 38 - c.bos[a]parc-gatinais-francais.fr

Construction Manager

Name : abdpa

Contact : Antoine Brochard - Architecte, Associé - 0175501481

Stakeholders

Function : Thermal consultancy agency

Function : Other consultancy agency

Function : Company

Contracting method

Separate batches

Energy consumption

Primary energy need : 80,00 kWhep/m².an
Primary energy need for standard building : 98,00 kWhep/m².an

Calculation method : RT existant

Envelope performance

More information :

Hemp concrete insulation on existing masonry.
Wood fiber, and hemp flax on the roof slopes.

Systems

Heating system :

Wood boiler

Hot water system :

Individual electric boiler

Cooling system :

No cooling system

Ventilation system :

Free-cooling
humidity sensitive Air Handling Unit (hygro A
Canadian well

Renewable systems :

Wood boiler

Water management

Recovery of rainwater for sanitary grey water, flexible tank of 8 m3.

Construction and exploitation costs

Total cost of the building : 525 000 €

Urban environment

The project is located in the center of Milly-la-Forêt, close to the town's facilities and shops. The plot of an old farm was divided during the creation of the house of the PNR of the French Gâtinais, realized by Joly and Loiret in 2009-2013. The barn remained unoccupied, without destination during the development of the site. It is located at the bottom of the plot, adjoining on two sides and with a variable level, which has complicated its use and rehabilitation.

Building Environmental Quality

works (including waste management)
water management
energy efficiency
integration in the land
building process
products and materials

Reuse : same function or different function

Batches concerned by reuse :

Structural works
Structural framework
Roofing
Facades
Indoor joineries

For each batch : Reused Materials / Products / Equipments :

The rehabilitation preserves the characteristics of the rural architecture of the barn: sandstone and limestone masonry, existing frameworks, flat tile roofs, zinc work... These elements are kept in place, reused in fact (132 m3 of masonry, 5.3 m3 of timber, 140 m² of tiles, 32 ml of zinc, 1 carriage porch...). Other elements are reworked, reorganized (flat tiles for the creation of roof windows, external doors condemned...).

The reuse also concerns the furniture resulting from the upcycling of wood of frame or joinery (oaks, fir, beech). From these materials, 6 individual desks, 4 double desks, 2 meeting tables and 8 storage boxes were made.

Field of use and material origin :

The integration company Seve Mobilier, based near Soissons, has collected, machined and assembled framework wood, floor elements or interior joinery, workshop scraps from the region.

Sustainable design

Reusable materials :

In our opinion, the project is a manifesto of biosourced architecture. It favors the use of wood (solid spruce, glued laminated spruce, spruce cladding, chestnut for shingles, plywood spruce, OSB, glued laminated beech staircase, solid exterior joinery ...) but also other ecological materials (hemp concrete, hemp wool in crawls, linoleum...).

Our will to limit the elements of second work in the project decreases the quantity of reusable materials: no false ceilings, furniture acoustic panels, cable trays and apparent cvc... As described below, the aluminum-glass partitioning of the offices is adaptable or recoverable in case of change of destination or evolution of the project partition.

The project also includes a grey water system (collector, flexible tank, pump) to reuse rainwater in the sanitary facilities.

Functionality economy, recycled and recyclable materials :

Great attention was paid to the selection of materials that are compatible with each other (primary structure, envelope and finishing work) and that correspond to the specific characteristics of an old building (interior lime coatings, hygrothermal compatibility of insulation materials, etc.). The choice of hemp concrete is particularly indicated for the insulation of old buildings, especially since hemp is cultivated on the territory of the "PNR du Gatinais" and that a processing industry is being installed near Malesherbes.

Reversibility / Adaptibility :

The interior partitions of the offices and glass doors were made of aluminum profiles and glass panels. Adapted to the height of the levels, they could be moved to change the configuration of the equipment.

Specificities linked to new materials :

Yes, in large proportions, see previous points.

The furniture of the third place was the object of three batches : one of furniture resulting from the re-use, the other of public purchases via the platform ugap, guaranteeing social criteria as well as the made in France, finally the crockery was provided by a ressourcerie.

Environmental assessment

Impacts avoided : water, waste, CO2 :

Little demolition in the barn, but adaptation of the existing. Much less impact than a demolition/reconstruction operation.

Categories	Avoided CO2 (kg)	Avoided water consumption (m3)	Avoided waste (kg)
Outdoor facilities	0	0	0
Exterior fittings / Locksmithing - Metalwork	0	0	0
Carpentry	302,8666667	4,8433	262,8357626
Partitions	0	0	0
Coverage	2216,76	11,6536	1223,181589
Roofing / Exterior fittings	0	0	0
Lighting	0	0	0
Safety lights	0	0	0
Climatic engineering equipment	0	0	0
Electrical equipment	0	0	0
Facades	0	0	0
False ceilings	0	0	0
False floors	0	0	0
False ceilings	0	0	0
Structural work	269406,6052	1818,211568	351022,252
Sanitary installations	0	0	0
Insulation	0	0	0
Exterior carpentry	0	0	0
Interior carpentry	173,326208	3,49438386	225,0903078
Furniture	1329,122753	12,36986045	901,8513461
Paint	0	0	0
Plumbing	0	0	0
Floor coverings	0	0	0
Floor and wall coverings	0	0	0
Wall coverings	0	0	0
Building security	0	0	0
Locksmithing - metalwork	0	0	0
VRD	0	0	0

TOTAL	Avoided CO2 (kg)	Avoided water consumption (m3)	Avoided waste (kg)
	273428,6808	1850,572712	353635,211

	Km in a small car	Nb of rectangular bathtubs	nb of years of household waste of a French person
Equivalent	2187429	12337	707

Equivalent trip Paris- Nice	2486,0

The reuse operation has saved the equivalent of 2187429 kilometers traveled by a small car, or 2486 Paris-Nice trips, 12337 rectangular bathtubs filled with water and 707 years of household waste of a French person.

Reproductibility and Innovation

The rehabilitation of barns is a theme shared by all rural areas, or rural that have become peri-urban. Our project, created in a particularly complex situation (jointness, interlocking....) can testify of the feasibility of this type of ambitious operations on the environmental plan.

Link between demolition and all trades work :

Carried out by the GO lot.

Storage of dismantled materials and management in situ reused materials :

Storage of the elements on pallets (tiles, doors...), transport to the companies' premises before re-use.

Social economy

Social economy and professional integration :

SEVE MOBILIER is a social integration structure with 6 employees and 25 employees on a professional integration path. Since its creation in 2015, more than 150 people have been trained and accompanied in the workshop.