About hansvalkhoff

Environmental and building research

EEHB conference Energy Efficiency in Historic Buildings

Last week my French colleagues from the CREBA consortium presented our project on the responsible retrofitting of traditional buildings during the EEHB conference on the Swedish Island of Visby.

You can find the article in the EEHB report (Energy Efficiency in Historic Buildings, p.274) : Report EEHB (2018) Energy-efficiency-in-historic-buildings

Later this month the website of the French national platform for responsible retrofitting of traditional buildings CREBA will go on-line. The CREBA conference will be held in Bordeaux on the 29th of November 2018. Click to inscribe.

Programme Colloque CREBA Centre de ressources sur la rehabilitation energetique du bati ancien

CREBA : Naar een verantwoorde verduurzaming van oudbouw

Het Franse project CREBA is in 2017 van start gegaan en wordt gefinancierd door het ministerie van Duurzame Ontwikkeling, via het programma voor energietransitie PACTE.

De website van het CREBA kenniscentrum voor ‘verantwoorde renovatie van vooroorlogse oudbouw’ gaat in september 2018 on-line. Behalve enkele tools voor de reguliere gebruikers van de website, zoals de Franse versie van de Guidance Wheel, bevat het een schat aan informatie over verduurzaming van erfgoed  en ‘traditionele’ gebouwen. Aan de hand van een selectie van voorbeeldprojecten van verantwoorde renovaties krijgen architecten, aannemers en huiseigenaren inzicht in de integrale benadering en de kwaliteitseisen die CREBA voorstaat. Sommige van deze projecten komen ook in aanmerking voor het toekomstige label voor een Verantwoorde Renovatie. De landelijke bekendmaking van kenniscentrum vindt plaats in november, tijdens eerste CREBA symposium in Bordeaux.

Net als de Britse STBA is het Franse CREBA een breed gedragen platform dat de kennis over verantwoorde renovatie ook uitdraagt in provincies en gemeenten. Waar we in het Handvest vooral op attenderen is de bijzondere kwetsbaarheid van vooroorlogse gebouwen, die in de verduurzaming een speciale aanpak behoeven. Hierbij zijn het materiaalgebruik en de vochtregulering van groot belang, iets wat de resultaten van de studie HYGROBA (2013) ook duidelijk laten zien.

De huidige partners van het consortium zijn : de regionale afdelingen van het ministerie van Duurzame Ontwikkeling, CEREMA (Bordeaux en Straatsburg), de School voor Architectuur in Toulouse, de Technische Hogeschool Paris-Tech en de erfgoed-organisaties, Sites et Cités en Maisons Paysannes. De ontwikkeling van de CREBA website is uitbesteed aan het bureau Stratis. De copyright van de Guidance Wheel blijft in handen van de STBA, die ook de programmering van de Franse versie doen en ons in de testfase begeleiden.

Back in the Netherlands

After having lived and worked abroad, I moved back to the Netherlands (Amsterdam area) last year. Currently I’m working as a consultant for the responsible retrofit of traditional buildings. Recently I’ve joined the sustainability working group Op Eigen Kracht in the old town of Edam where I now live.

Logo Op eigen kracht

I still work as an associated researcher and lecturer at the School of Architecture in Toulouse (France). I am one of the initiators of the French platform for responsible retrofit CREBA, which will launch its website this summer. At the end of this month I’ll welcome my French colleagues to the old town of Edam for the next steering committee meeting. We’re almost ready to launch the French version of the Guidance Wheel, a decision making tool for retrofit of traditional buildings. During the CREBA meeting the Dutch NGO, Groene Grachten, will present their tool: De Groene Menukaart.

 

CREBA ‘en route’

The project for the French resource centre on ‘responsible’ retrofit of traditional buildings, CREBA, has started with two consortium meetings this year in Strasbourg and Bordeaux. At the June conference of the national Building Quality Agency AQC in Paris one of the project partners will present the CREBA project and brochure to a wider audience. In the meantime, together with the STBA, the School of Architecture in Toulouse is working on the French translation and adaptation of the Guidance Wheel. Other partners have started gathering references and examples of best practice in retro-fitting to supply the future resource centre. Another presentation will be given at the annual congress of the heritage organisation Sites et Cites Remarquables de France in Calais in September.

Download the brochure: CREBA-plaquette 2017

Resource Centre

The French ministry programme PACTE has awarded the project CREBA with a two year subsidy. This will allow us to develop a national resource centre on ‘responsible’ renovation of traditional buildings, built before 1948. The future website will contain the latest publications, guide books, scientific references and reports on sustainable renovation. It will also provide case studies and ‘decision making’ tools for house owners, architects, developers and builders. It will host the French version of the Guidance Wheel developed by the British STBA.

image-logos-creba

Members of the project consortium are CEREMA in Strasbourg, the School of Architecture in Toulouse, Arts et Metiers in Paris, Maisons Paysannes, and the heritage organisation Sites et Cites remarquables.

The official announcement of the project was made at the European Biennale of Urban Heritage, the 4th of November, during the symposium on Historic Town Centres in Cahors.

logo pacte

Autumn renderings

detail-colombage-ruelle

Finally getting onto the finishing work on the front of the house on the street side and in the alleyway. All the interior timber and wattle and daub walls have been restored with a light mix of lime and flax (straw). This was followed by a last coat of lime plaster for which I used air lime (CAEB) and two types of sand (sable calcaire) from a  local lime stone quarry, giving it either a nice creamy, or ochre coloured finish, which matches the colour of the original daub. The other walls have just had a whitewash finish directly onto the lime and flax render.

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Timber frame alleyway

The last big project was the restoration of the timber frame facade in the alleyway. The top floor had already been restored in 2008, with a whole new infill of ‘fresh’ daub made from old walls to which I added some sand and straw. The old daub panels on the first floor were in bad shape and still needed repair. This time I didn’t use new daub but chose a more commonly used traditional technique, filling the bigger holes with a mix of lime mortar and bits of old terra cotta tiles. The main advantage being the shorter drying time – daub takes a few months to dry. I used a special hydraulic lime (Boehm NHL-2) which is not too strong and compatible with vernacular materials. This lime has definitely air lime qualities and the mortar doesn’t set immediately if kept overnight under a film of water, making it still usable the next day.

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Wattle and daub before restoration

The infill was followed by a first coat of lime render (corps d’enduit) to which I added some flax straw (horse bedding) to stop it from cracking. For the finishing layer I used an earth plaster made from crushed old daub, sieved at 2 mm, to which I added an ochre coloured quarry sand, also sieved at 2 mm, and a little bit of lime (about 20% of NHL-2). The render was applied with a plaster knife and then worked by trowel to get a smooth finish, which the French call a finition serré (‘tight’ finish).

Winter 2016

We took a bit of a winter break after more than a year of renovation. It’s now only a matter of painting and finishing, to get the front of the house ready. For the interior daub walls we use natural lime wash, with alum salt to stop it flaking and a bit of clay pigment for colouring. For the interior windows and doors we use linseed oil, or eco paints (Aquamarijn and Biopin) and hard oils for the staircases and pine floors. The fitted kitchen is made of solid birch panelling (not on photo yet).

Click on photos to zoom

Kitchen before decorating

Kitchen before decorating

Hall way and downstairs toilet

Hall way and downstairs toilet

Timber frame in bedroom

Timber frame in bedroom

Pine staircase to attic

Pine staircase to attic