The conference was held in Berlin, between the 18th and 20th of November.  The main emphasis was on innovation and new materials and the future of earth building, but with reference also to the advantages of building in earth, in particular, healthy living.  About 170 delegates and speakers attended from 24 countries.

Berlin,

The venues for both The Conference and the Earth Exhibition were in the former East Berlin.  The conference itself was held in a 19th-century church, which had been extended and very skilfully converted into a superb conference centre.  The exhibition was also held in a church which, by comparison, was rather cramped for both exhibitors and visitors.

Schoenefeld airport is also situated in the former East Germany.  The 13 Mile Drive from the airport into the city gave us a brief taste of East Germany.  Neglected and derelict buildings peppered the route and one had the impression of being in a very rundown and unfashionable part of the UK, though I doubt if there are still parts of the UK that could match the dereliction in this part of East Germany.

East Berlin is still dominated by endless grim imposing blocks of apartments and shops that are the legacy of the Soviet period.  In the centre of Berlin, extensive redevelopment is underway.  One of the main thoroughfares through the city, previously known as Stalin Allee and now renamed Karl Marx Allee and Frankfurter Allee, is dominated by 8 and 9 story blocks of apartments built mainly in the early 50s as the Soviet's response to the largely American sponsored redevelopment in the West.   Some claim these apartments, which must have been regarded as pure luxury in an otherwise devastated city, were given exclusively to party members.  But one German we met said that her father, not a party member, had been allocated one, as had many ordinary Germans.  With the re-unification of Germany, these apartments have been ‘listed’ and have become fashionable with West Berliners.  A German version of gentrification.

Graffiti. One cannot visit Berlin without commenting on its graffiti.  Our first thought was that we had chosen a hotel in a very unsavory and probably unsafe part of the city.  However, as we walked into the city centre from our hotel, it became evident that Berliners can only sleep peacefully when they have successfully covered all accessible parts of their buildings with graffiti.  Indeed graffiti can sometimes be seen on the roof tiles of buildings, seven storeys high, where access must have been gained through a skylight at some considerable risk to the artist.  Nor is much attempt made at cleaning it off.  Some prestige buildings have the lower walls painted, presumably in an attempt to cover and re-cover the artist’s work, but most seem to accept it as we might accept commercial advertising, intrusive, but ultimately harmless.  Is this a response to the grim repetitive Soviet architecture?  Perhaps, but I was assured this phenomenon is not confined to the East, and can be seen right across Berlin.  Some of it is truly artistic, some racist, but most incomprehensible to a non German speaker.

The Conference.

As with all such events, the quality of Speaker and the degree of interest in the subject matter varied considerably.  I shall comment here only on those papers that appeared to add new knowledge or insight to the subject.  The two conference languages were German and English with simultaneous translation.  However, written German papers were not translated into English, nor English papers into German.

Healthy living

Vaastu Architecture.

This theory or belief originated in India.  If you are comfortable with notions of lay lines, force fields and cosmic energy, you may find Vaastu architecture has something to offer.  The belief seems to centre on the number nine, on the arrangement of rooms, the dimensions of rooms and walls (which must be multiples of nine) and the aspect of the room according to its use.  Get it right and your ‘soul’ will be at peace.  Needless to say, opinion was sharply divided.

Health advantages of earth

This was a more practical talk by a German medical practitioner.  There is a German Institute of Building Biology which investigates the effects of modern building materials.  He emphasised the ability of earth to regulate humidity and pointed out the importance of maintaining humidity at around 45% with an internal temperature of 21° C.  When humidity levels drop below the recommended range, VOCs and other harmful substances can be released from the building fabric, as well as from furniture and fittings.  He recalled an instance of a German school closing because of formaldehyde contamination.  He suggested 40% was the minimum safe humidity level and that bedrooms were the most important rooms to consider.  He recommended the use of massive earth walls in wet rooms to regulate humidity.  He pointed out however, that excessive air changes resulting from open windows or from a lack of air tightness in the building envelope will neutralise the effect and the advantages of earth.

Earth in Non-Domestic Buildings

Some speakers gave details of recent projects, where rammed earth walls had been used in public and commercial buildings in Germany.  These walls were non load-bearing and had been incorporated, because of their visual effect, as well as to add thermal mass to assist summer cooling.

The Use of Sisal Vegetable Fibre as Reinforcement in Compressed Earth Blocks.

This was a well researched project carried out in Kenya. It involved a series of experiments using various amounts of sisal and cement, added to compressed earth blocks to improve compressive and tensile strength.  It was no surprise to learn that the addition of cement increased the strength of the blocks.  What was more surprising was that sisal, without cement, had an even greater effect.  Cutting and mixing the sisal is labour-intensive but this does not present difficulties in a country with an abundance of cheap labour.  The optimum amount of sisal was found to be 0.75% by weight.  Above this, and the strength began to reduce.  Blocks made from the raw earth, achieved strengths of about 4.7N/mm².  This increased to 9.14 with the optimum amount of sisal.  The cement stabilised blocks achieved a strength of 8.24N/mm² with 12% cement content by weight.  Interestingly, small amounts of cement, e.g. 5% had the effect of reducing block strength.  Combining both sisal fibre and cement was even less successful.  With 12% cement and 1% sisal, a compressive strength of just 5.99N/mm², was achieved.  The tests also demonstrated that flexural strength increases more or less proportionately to compressive strength.

Earth Plasters

This is an area where the Europeans generally and the Germans and Dutch in particular, seem to have left us way behind.  In Germany, the most common use of earth in modern buildings today is the use of earth plaster, even where no other sustainable materials have been used.  Ready to use, off-the-shelf bags of earth plaster, are as convenient as any gypsum plaster.  Coloured plasters seem to be very popular, and a wide range was available.  Earth plasters are applied in two or three coats with the base coats containing the coarsest fibre.  Many of these products are available in the UK through various UK importers (e.g. Construction Resources).  It can be argued that transporting bags of earth, up to 800 miles from central Europe to the UK is not particularly sustainable. However, demand has to develop before a UK producer will make the necessary investment.  These plasters contain no artificial additives.  They are a blend of earth, sand and (usually) straw that will not crack, if correctly applied.  They can be repaired at any time by rewetting the surface.  Some speakers used videos and photographs to show impressive examples of the use of coloured and textured plasters, almost developing it into an art form.

Rammed earth in the UK

Dr Peter Walker, of Bath University, described recent developments in rammed earth in the UK.  He is well placed to do this having recently published a 'code of practice.' based on research work at Bath, funded by the Department of Trade and Industry (DTI).  The book is entitled Rammed Earth and has Rowland Keable, Joe Martin and Vasilios Maniatidis as co-authors.  This is the first authoritative guide on rammed earth in the UK.  It is published by the BRE. Bookshop and is a must for anyone contemplating rammed earth construction.

Earth building in East Germany

There are said to be between 50,000 and one million earth buildings in East Germany; dating back to the 17th-century.  There is a slow but steady increase in the number of new earth buildings each year.  One speaker, a small builder in East Germany, reported that he constructed about three new earth houses each year.  Rammed earth seems to be the most popular form with combinations of light earth and timber also quite common. He highlighted the difficulty of maintaining a good airtight structure with timber framed buildings and earth infill panels.  He pointed out that the two materials will inevitably shrink from each other, resulting in cracks.  He was against using modern sealants, preferring a high maintenance regime using earth as the filler. The main deterrent to greater use of earth in Germany seems to be cost.  Demand for earth comes mainly from environmentalists and those concerned with creating a healthy internal environment.

Earth as an industrialised building material

A number of speakers touched on this area, and at the end of each day’s lectures, the subject cropped up again in open forum.  Some countries, the UK and Spain for example, have no specific earth code or standard.  A speaker from Spain identified this as the main impediment to increased earth building in that country.  The general view from most German delegates favoured regulation, standardisation and certification of earth products.  They pointed out that designers would not specify earth products unless they were manufactured to a Eurocode and certified by an independent assessment body.  A Dutch delegate, who manufactures earth plasters, took the opposite view. He argued that at present, earth was a material available to everyone, from self builder to major developer.  Insisting on a range of expensive tests before any product could be specified or used, would disenfranchise most small earth builders and manufacturers, giving monopoly control to a few large and well financed companies.  It occurred to me that the earth industry may divide, as has the conventional building industry to a large extent, between an urban, industrialised, large-scale, investment driven industry in the cities, contrasting with a small-scale, craft based, almost cottage industry in rural areas. 

Excursions

The ACUD cinema

With the conference finishing on Saturday, Sunday morning was given over to a choice of four excursions.  We opted for a visit to a small arts cinema recently completed, where earth plaster had been used in the auditorium.  The cinema is run as a co-operative and it was the co-operative members who carried out the plastering work.  Earth plaster was chosen because of its ability to regulate humidity within the auditorium.  This is a very small cinema, with at most 150 seats. Nevertheless, the amount of moisture vapour given off by a full house would be very high, probably beyond the capacity of 12 mm of earth plaster to regulate.  The building appeared to have no other sustainable materials, being composed mainly of reinforced concrete and some of us came to the conclusion that the plaster was used more by way of a palliative, helping the co-operative members to feel better about their building without really having any significant environmental impact.  But then again, why do we have to justify the use of earth products?  We are never required to justify the use of gypsum or cement.

Chapel of reconciliation

With the organised visit over, a group of six of us decided to visit the Chapel of Reconciliation, close to a preserved section of the Berlin Wall.  The original chapel had been in the direct path of the wall and had been demolished to make way for its construction.  With Germany reunited; the church has been rebuilt using rammed earth.  Rubble from the former church was still lying around when the new church was reconstructed and some of these brick fragments have been included in the new earth walls.  The walls floor and altar of the Church are of rammed earth, the walls forming an oval shape, protected by an outer shell of open timber boarding.

                 Exhibition

The exhibition contained examples of earth products, along with other sustainable building materials.  The materials exhibited included: - Hollow clay heating panels, un-fired clay blocks, (some moulded some pressed), clay plasters of every description and colour, hemp insulation, natural paints, substrates for plaster made form reed or rigid clay panels, ground sourced heat pumps and rainwater recovery systems.