Mellé-en

1. 138
How to sustainably renovate
your heritage building - an eco-
housing demonstration.
Key dates
Construction : 17th
century
Design work : 02/2012
Building work : 05/2012 –
12/2013
Introduction
Saint Brieuc
Quimper
Vannes
Rennes
Mellé
Mellé
This eco-housing demonstration represents an exemplary renovation of
a 17th century house, through the enhancement of rural heritage and
sustainable development. This project combines energy performance,
natural materials, know-how and local expertise.
This project will enable many people to discover how heritage buildings
can be restored. It demonstrates the characteristics of the historic building,
particularly construction techniques specific to the local region.
Overview - Photo © Servane Guihaire - Constructys Bretagne

2. www.libnam.eu 2
Context
Like a number of rural
communities, Mellé has seen
much of its population leave
to move to suburban areas,
resulting in a loss of farmland.
Its distance from employment
catchment areas has been the
major factor in this population
decline.
To provide practical solutions
to these environmental
challenges, the borough
has been committed for
many years to a global
sustainable development
project. It actually becomes
necessary to limit the
utilisation of agricultural land,
to effectively construct and
renovate buildings, but also
to promote the development
of renewable energy.
The thermal performance
obtained through this
renovation is based on the
skill of the architect and
on a study conducted with
Thermal Dynamics Simulation
software «PLEIADES
COMFIE». The technical
advice of a consulting firm
specializing in airtightness
and hygrothermal issues
supported the technical
choices taken during the
project.
Plan © TRICOT Architecture
N

3. French-British collective Libnam3
Building overview
This 17th century house was
constructed using local granite,
earth, and lime. It includes a first
floor and a gallery in the north
façade. Like many buildings of this
period, the house is semi-detached
and has just three openings in the
south façade.
As a teaching aid the eco-housing
demonstration presents various
technical solutions to wall insulation.
The north façade was composed of
a simple wood panel and an unused
door. This was replaced by a timber
frame with wood fibre insulation,
further insulated from the outside
by wood fibre rendered with a lime-
sand mix. The interior was finished
with painted plasterboard.
The south and west facades were
insulated from the inside using
lime-hemp brick, whilst the gap
between the original wall and the
partition wall was filled with loose
hemp, permitted by the building
regulations. The walls were finished
with a lime render.
A timber frame filled with flexible
«excelsior», or wood wool, was used
for the interior of the shared wall to
the east. Rigid wood wool with an
air gap of 3 cm between the stone
wall and frame was used for the
exterior. A wooden cladding was
used to finish the bedroom and the
living room, and plasterboard was
used to finish the bathroom.
Laying of geotextile - Photo © Pays de Fougères

4. www.libnam.eu 4
Cellulose fibre (recycled newspaper)
40cm deep makes up the loft
insulation. The ground floor is
insulated using loose cork between
the joists of the local oak parquet
floor.
A wooden pellet burner was chosen
to heat the building. Finally two
skylights, one in the stairwell and
the other in the bathroom, add
natural light to every recess of the
house.
Lime /hemp brick - Photo © Pays de Fougères
Technical focus :
The ground level floor
Mellé, like many boroughs in
Brittany, has a granite subsurface
with a very real risk of radon
pollution. A great deal of attention
was paid to the insulation and
ventilation of the ground level floor
to mitigate this risk.
In addition, the borough has
chosen to develop local know-how
using a parquet floor on joists and
supporting blocks of blue granite
from Louvigné. This technique
allows space for a network of
ventilation pipes within a «hérisson
de pierres» or layer of loose stones
(stone size of 20/40).
A Geotextile Membrane was then
applied to ensure airtightness while

5. French-British collective Libnam5
Barriers and solutions
During this exemplary public
project with high environmental
demands, the objective was to
generate feedback on costs, results
and training for businesses. The
businesses were hired by means of
public tender.
The project was long ; the numerous
different renovation techniques,
External insulation - Photo © Pays de Fougères
controlling moisture migration.
The cork, used for insulation, is
not a regional product but was
used because its properties are
not affected by water; the rotproof
nature of cork makes it ideal for
underfloor use. Finally the joists and
parquet are made of local wood
fabricated by a local craftsman.

6. www.libnam.eu 6
Focus on a cross-
disciplinary theme : an
awareness tool
This eco-housing demonstration
wasdesignedasateachingtoolopen
to all. It is the sixth demonstration of
the new «Route of the energies», as
coupled with building layout
(long, narrow and on two levels),
complicated the sequence of events
and therefore the coordination of
the various businesses. Furthermore,
the airtightness work carried out
on the old building was more
complex because of the special care
necessary for a quality finish.
Many unforeseen problems related
to the nature of the subsoil (unsound
walls because of the unstable sandy
soil) lengthened the renovation.
The chimney flue no longer met
modern building regulations and
was condemned.
The mason was able to implement an
unknown technique - hemp blocks -
which did not pose a problem as the
mason was accompanied during the
work.
Throughout the project Stéphanie
GeslotofPaysdeFougereswasgiven
the role of demonstrating the value
of «green» building airtightness,
as well as the installation methods
for high performance technical
membranes. The various craftsmen
had to adapt to these new technical
requirements. This pilot project
allowed them to learn new skills
opening up new markets.
Finally, a blower-door test was
carried out at the end of the project
by the company Ty eco² as part of
the on-site training. This airtightness
leak test indicated a renewal rate of
air at 5 vol/h. (index n50) or 0.73
m3/h.m² (index Q 4Pasurf).
Exterior - Photo © Servane Guihaire - Constructys Bretagne

7. French-British collective Libnam7
The town hall of Mellé rent this
renovated house. Since the 1st
of March 2014 this new tenant
pays a small rent in exchange for
«educational» visits by appointment
only. There has been no significant
monitoring of energy consumption
to date. The thermal study carried
out using the prescribed ‘Perrenoud’
software estimated the heating
system to have an energy use of 33
kWh/m²/year. In real terms 4 x 15kg
sacks of wood pellets are used every
2 months.
Finally the visual comfort afforded
by the skylights, the acoustic
benefits despite the adjoining wall,
and the thermal comforts from the
high performance materials used
make a perfect little nest to live in!
Performance
part of the flagship local sustainable
development project in the borough
from 2008 to 2014.
Educationalinterpretationwillbeput
into place to give an understanding
of the project to visitors, with
explanations on the choice of
techniques and the importance of
the associated studies. This signage
will be fun and interesting.
Stove - Photo © Servane Guihaire -
Constructys Bretagne

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Stakeholders
Project owners : Borough of Mellé (Mellé)
Project supervisor : TRICOT architecture
(Louvigné du Désert)
Consulting firm (Thermal and liquids) :
THALEM Ingénierie (Bruz)
Site coordinator : Pays de FOUGERES
(Fougères)
Structural work : SARL ROUSSEAU
(Louvigné du Désert)
Tiling : SARL LAIZE (Romagné)
Skylights : SARL MARSOLIER (La Chapelle
Janson)
Electricity, Heating, Ventilation : SARL RAUT
(Javené)
Plumbing : SARL DELALONDE (Pontmain)
Decoration (painting) : SARL HEUVELINE
(Gorron)
Insulation, plastering : SARL BREL
(Lécousse)
Interior and exterior joinery : SARL VIVIER
(Mellé)
Wood pellet burner : GALLE (Romagné)
Costs
Consulting firm : £3,310
Project supervisor : £11,946
Structural work : £35,246
Interior and exterior joinery : £29,408
Insulation, plastering : £5,995
Decoration (painting) : £3,737
Plumbing : £4,925
Electricity, Heating, Ventilation : £6,803
Skylights : £3,977
Tiling : £1,350
Wood pellet burner : £4,251
Total : £92,769
Total all taxes included : £110,948
Surface area : 68 sq m
Total per sq m : £1,364
Total per sq m all taxes included : £1,631
South facade (left) and east gable (right) © TRICOT Architecture
Contact
Pays de Fougères
http://www.pays-fougeres.org/