Each Beosite product has to be individually developed, and its development typically requires about six months of research. Some important aspects are:
The two basic types of interest are:
Anhydrite : CaSO4 + 1/2 H2O. Has a lower water content, hardens in 1 1/2 hours. For your guidance, this costs between 2 1/2 - 3 US cents per kg in Europe.
"Cheap" gypsum : CaSO4 + H2O. Has higher water content, hardens in less than 30 minutes. This is what is discarded during gypsum production. It costs between 4 and 5 1/2 US cents per kg in Europe. (The price of top quality gypsum is between 9-10 US cents in Europe)
Conserve three sets of the carefully coded dated and labeled samples in sealed plastic bags. Keep the bags in darkness at about 18 degrees C.
b) Collect two samples each of about 300 grams taken from the walls of existing houses, at least 5 houses from each of 5 areas. The samples must be carefully coded dated and labeled with location, age, type of mixture used (eg % straw, % clay, %dung) plus a careful description with percentages of any other extra materials (additives etc) included in the mixture, description of the building method used.
c) Send one set of the samples under b) to the Consultant.
d) Test one set of the samples under a) for their hardening time. Record the date and hardening time on the labels OF THE HARDENED SAMPLES ONLY.
e) Collect samples of fine milled sand and/or desert sand (the sand on the leeward side of hills is finer than that on the windward side). You may use several types of sand, in which case the procedure under phase two is to be conducted with each type of sand.
a) For each raw anhydrite or cheap gypsum collected under a) above make sample blends each blend containing 50% of sand and 50% of the raw material concerned. Each such blend must be carefully coded, dated and labeled. Use EXACTLY the same quantity for every such mixture.
b) The following must be conducted exactly. Hold in reserve before proceding with point a) a reserve container with EXACTLY one third of the amount of water used in a), and a second reserve container with EXACTLY one third of the amount of anhydrite or cheap gypsum used in a)
The blend in a) must be just pourable, so that the mixture is just able to flow. If it is too liquid add some more anhydrite/gypsum, if it is too thick add some more water.
c) Carefully record hardening time, the EXACT percentage of extra water or raw material added, and code, label, and store the new composite products.
d) Copy to us all a full documentation on everything done on raw materials, sand and material mixtures, wall samples to date.
b) You then prepare two sets of each mixture according to the recipes given, and carefully code and label them. One set is tested for ageing. The second set is to be kept in a labeled plastic bag in a dark place at a temperature of around 18 degrees Centigrade, preferably without air.
c) From your own recorded observations and from your paper-work, we can then assume which material(s) are likely to give the best results.
d) The UNTESTED examples of the best material(s) are then sent to us so that we can conduct mirror tests for counterchecking purposes.
b) A simulation project is then set up with, say, 5 houses in each of say 5 regions, each house with 5-10 check points. Ideally the houses should be the ones the samples under 1 b) come from. If other houses are involved, then collect samples for them as set out in 1 b) above, code them, label them and pack them well.
c) Apply the recommended mixtures to the walls of the chosen houses, carefully recording:
-code of mixture and code of wall sample
-date and time of day
-weather conditions
-humidity at the moment of application
-details of mixing
-size of mix
-number of people working
-ease (feel) of application
-comments of workers (seems too thick, seems too thin)
-hardening time
-ALWAYS with exact measurements of quantities etc
c)Every week thereafter at exactly the same time, check the control points:
- is the material still strong
- description of climatic events over the week
- tears or signs of tears with description of length and width of tears indicating whether they are on the North, South, East or West side of the house
- if the moisture feels uniform to the touch at the top and at the bottom of the walls and around the doors
- check uniformity of colour
- check if little black spots appear, especially towards the bottom of the wall
- check carefully what happens at the bottom of the wall in contact with the soil, by tapping the wall with a stick and listening for "empty" sounds.