Lunch with the Mayor of Berlin

The last week has seen a bit of a departure from our project on efficient wood-burning stoves as we've been supporting Seb Kaminski, an engineer from Arup in London, who's visiting for two weeks to lay the groundwork for a structural analysis of REDES' earthquake resistant bahareque houses. Bahareque is a traditional construction method, a type of wattle and daub that uses barra de castilla (a thin bamboo that grows to heights of 5 or 6m) for the woven frame of the walls. REDES' design incorporates a galvanised steel portal frame which is cheaper than using imported timber or bamboo and diagonal bracing with tensile wire. The barra de castilla is then attached the framework and left for a week or so to dry out - the projects are done in a participatory way with each beneficiary family providing someone to work as unskilled labour. Groups of 4 or 5 families work together on all the houses in their group which helps to provide the time needed between phases of construction (eg. for the barra de castilla to dry or the mud walls drying before plastering etc.) The finished houses are whitewashed and then painted by the families, resulting in a "modern" looking house far more desirable than their old adobe houses.

REDES are particularly keen to develop this bahareque design as it is 15% cheaper than the equivalent made from blocks, and more importantly the investment in materials goes to incredibly poor rural areas rather than the rich elite who hold monopolies on the block factories. Additionally it uses a much smaller amount of cement, which is both expensive and environmentally damaging (its production is energy intensive and a major source of industrial carbon dioxide emissions) and barra de castilla is a fast-growing, sustainable and carbon-neutral resource. A structural analysis has already been carried out by an independent local company, but in order to secure international donor funding and governmental support for rolling out a larger bahareque project REDES would like certification from an internationally renowned company, which is where Seb and Arup come in.

As well as a number of technical meetings with the REDES engineers who designed the houses Seb has a questionnaire for families who have participated in the project, so over the course of the fortnight that he's here we will visit three different communities to do a visual assessment of the houses and hear the families' views. As a result we spent last Friday visiting Loma Fria where REDES are currently building rainwater collection tanks for the bahareque houses. It was very interesting talking to the families, the vast majority of whom were delighted with their houses and no longer worried about the threat of earthquakes. For those who don't know, El Salvador suffered two major earthquakes (6-7 on the Richter scale) in 2001 which killed hundreds of people. Everyone we talked to in Loma Fria had their old adobe houses severely damage during the earthquakes, although none of their relatives had died. One of the supposed advantages of bahareque is that it is extremely light and flexible - certainly when compared to the traditional adobe walls with loose blocks and tiled roofs it is easy to see the improvement in the design.

Another advantage of the new houses is their resistance to insects, in particular assasin beetles (los chinches) which tend to live in the nooks and crannies of old adobe houses and emerge at night to bite the sleeping residents. These seemingly harmless bites can transmit Chagas disease - it often goes unnoticed for tens of years, but eventually damages the nervous and digestive systems and can also cause heart failure - something that we are particularly aware of after there was a worry that one of the group from Imperial was showing symptoms, luckily it turned out to be a false alarm.

Nevertheless there are also some problems with these houses - the quality of the welded joints is dubious, most are only spot welded together and their resistance to earthquake loading will be minimal at best. The houses are also prone to surface cracking as the plaster dries so quickly in the roasting heat, and the thin, light walls desirable for earthquakes heat up much more quickly making it uncomfortable to sleep inside during the day. On top of that there's a problem of social acceptance that is harder to overcome than all the technical challenges - some people simply do not want a house made out of mud, whether its been nicely painted or not, and would be much happier with blockwork walls.


Jumping back to Wednesday and the title of the post, we attended the inauguration ceremony of the second phase of a batch of 70 REDES houses in Berlin (where Steph and I will be returning in a couple of weeks time to interview families from the first phase about the stove that came with the house) where the funding has come from Castilla La Mancha with support from a Spanish NGO - Terra Pacifica. It turned out to be a very interesting day listening to the various speeches from all the players - the Mayor and Town Council, comunity leaders, Terra Pacifica and finally REDES.


I also picked up a few pointers on how to get the comunity involved in this type of event - for example reading out the contract for the next phase seemed like a good idea, but perhaps some of the finer legal details could have been omitted! The ceremony was followed by lunch at a little restaurant perched at the top of the hill overlooking the whole valley and Embalse 15 de Septiembre - one of the main hydropower sources for El Salvador. Douglas even managed to rustle up a group of Mariachis to serenade us and celebrate Jose's (one of the Spanish delegation from Terra Pacifica) birthday.