How to renovate historic
timber-frame buildings in SW
France up to thermal
insulation standards ?
while preserving the
environment,
preserving the building’s
vernacular qualities,
reducing embodied energy
and embodied carbon of the
rehab project
Timber-frame heritage
Mirepoix (09) main square
French context French government programme : 40% cut in GHG
emissions of housing sector by 2020 20 million dwellings to be renovated and
thermally insulated French thermal regulations are not yet applied to
historic and old buildings (built before 1948) Dry lining can do much damage to vernacular
buildings
1.‘Conventional’ interior insulation techniques : glass wool and plaster board
2. ‘Ecological’ interior insulation techniques : wood wool, cork and cellulose
3. Interior insulation with plant fibre and binder : hempcrete, earth&straw, woodchip&lime
4. Exterior insulation : polystyrene, wood fibre board, wood wool and cladding
Impact assessment : 20 wall types
Assesment tool COCONScores for 6 parameters : Embodied energy (kWh) Embodied carbon (kg CO2 eq) Resource depletion (kg Sb eq) Thermal resistance (m2K/W) Decrement delay (h) Thermal inertia (kJ/m2K)
Overall scores per wall type
0.0
2.0
4.0
6.0
8.0
10.0
12.0
14.0
16.0
18.0
M1 M2 M3 M4 M5 M6 M7 M8 M9 M10 M11 M12 M13 M14 M15 M16 M17 M18 M19 M20
Ove
rall
scor
e (1
-20)
Wall type number
Overall scores (1-20)
Conventional
Ecological Plant fibre Ext. insulation
Best overall scores for walls with exterior insulation made of wood fibre board
Worst overall scores for ‘conventional’ walls (dry lining)
Bad overall score for ‘ecological’ monomur Plant fibre ‘infill’ is a good alternative if
exterior insulation is not possible Hempcrete wall gets low overall score
Results
0
50
100
150
200
250
300
350
400
M1 M2 M3 M4 M5 M6 M7 M8 M9 M10 M11 M12 M13 M14 M15 M16 M17 M18 M19 M20
EE
(kW
h/m
2)
Wall type number
Embodied Energy (kWh/m2)
-100
-50
0
50
100
150
M1 M2 M3 M4 M5 M6 M7 M8 M9 M10 M11 M12 M13 M14 M15 M16 M17 M18 M19 M20
EC
(kg
CO
2eq
/m2)
Wall type number
Embodied Carbon (kgCO2eq/m2)
mono m
ur
wood chip
mono m
ur
woodch
ip
eart
h &
stra
w
Not one optimum solution Earth&straw is very compatible with daub
walls and local economy, but labour intensive Lack of data for ecological building materials Need to take hygrothermal properties into
account Consensus that hygroscopic and breathable
insulation materials are better for buildings
Conclusions
HYGROBA research project : • Insulation solutions for old buildings that
don’t disturb their hygrothermal equilibrium • 5 wall types from existing buildings• Hygroscopic versus non-hygroscopic• ‘Breathable’ versus ‘non-breathable’ • Hygrothermal simulations WUFI 2D
The paper is based on the research for an MSc in Architecture at the University of East London and the Centre for Alternative Technology (UEL/CAT, 2010)
Hans Valkhoff, freelance researcher at LRA-ENSA Laboratoire de Recherche en Architecture
(Toulouse, France)
Link to PDF thesis: http://www.areso.asso.fr/IMG/pdf/ThesisHansValkhoff-r-moyen.pdf
Thanks for your attention