| Archive for Downsizer For an ethical approach to consumption |
| Bulgarianlily |
Rammed earth wallI have just spent a week, with two volunteers, building a rammed earth wall. I thought you might like to hear about it.It is the back i.e. north facing wall of our greenhouse and will form the central wall between the greenhouse and a storage shed, so will be internal when all this is finished. I wanted to try to build a heat storage wall to see if this would help us grow crops in our cold winters. I had a problem in that the storage shed required us to dig out a slope giving me a lot of poor silty earth to put somewhere, so I thought why not put it into a wall? There is no clay on our property, and the soil is very fine textured, full of silt and mica, and turns to instant increadibly sticky mud when wet, so therefore I decided to use a cement stablished wall, aiming at 7% cement. It is four meters long and 2 high, on a slipstone cast foundation. I constructed a wooden frame first to hold up the greenhouse as we needed this working this year, and then used a cheap blue tarp to windproof the greenhouse so we could get our tomatoes in. The wooden frame was extended out to make it possible to put in wood planks for shuttering, 40 cms across. We used a cement mixer to mix the soil and cement, five buckets of soil to just under a half of cement, and short sections of 15 x 15 cms and 10 x 10 cms offcuts were nailed to handles to make tampers. The mix was damp enough to squeeze into balls in your hand but not really wet. We put it into the wall in about four inch layers and pounded it down with the tampers. It was awkward to work round the shuttering I constructed and in future I would use commercial hired shuttering. If I was building a large structure, I would also get some kind of wacker or rammer, air or electric driven, and make sure I had good scaffolding to work off. It was very hard work to make the wall, given our summer heat, but the shuttering could come off almost immediately, and the wall is on the whole smooth and very good, it also took a clay and chopped straw plaster the next day (we neeed to do a test of this as one of our volunteers was leaving and wanted to see how to do this). I am quite happy with what we have built, but need to balance in my mind the enviromental effects of using cement, compared with our problems with subsoil disposal. I need to also do a test run with no cement and see what happens. The costs are interesting, at 40cms thick we used 3/4s of a bag, i.e. 37.5 kilos of cement a sq meter. The wall cost us therefore 6 x 50 kilo bags, at 9.20 leva each, around 25 pound sterling, or three pound a square meter of wall. A 12 meter by 6 meter house would therefore cost us 270 pounds in cement for the walls, the soil being dug up from the foundations. I would welcome comments and also suggestions for what power tool would be best for compressing or vibrating down the walls, given that I hate 2 stroke engines with a passion. If anyone can also give me some idea of how much cement is used in different types of wall, that would also be very helpful, i.e. in brick, concrete block etc. Thanks. If I can figure out photos I will post them. |
| marigold |
I've got a copy of this book - it has lots of information on how to build homes using pise de terre as well as cob and chalk. The technicalities go right over my head, though I find the subject interesting. All the construction work was done manually in those days, but it may be worth a squint. |
| Bulgarianlily |
Thanks, will give that a read asap. |
| vegplot |
Earth Construction - A Comprehensive Guide (Houben and Guilaud) is good if a little technical and academic. ISBN 1-85339-193-X |