Hans Valkhoff

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 Mirepoix (09) main square

 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

Scores for 6 parameters :  Embodied energy (kWh)  Embodied carbon (kg CO 2 eq)  Resource depletion (kg Sb eq)  Thermal resistance (m 2 K/W)  Decrement delay (h)  Thermal inertia (kJ/m 2 K)

ConventionalEcologicalPlant fibreExt. 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

mono mur wood chip mono mur woodchip earth & straw

 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

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: moyen.pdf moyen.pdf