The covering of the furnace consists of loam. Loam is an ideal material for this purpose. It is easy to work with and has very good heat containment properties. I got my loam from a friend's basement excavation.You will need approx. 1 to 1.5 cu meter (1.3 to 2.0 cu.yards).
What is loam?
Loam is a mixture of sand, silt and clay. It is formed the decomposition of these components by rocks or is formed by being deposited. Loam is among the oldest building materials known to mankind. Loam construction techniques have been known for over 9000 years and up to a third of the world's population lives in loam houses today.
Characteristics of the loam:
- Loam is good at both retaining heat and insulating (hot inside the oven, not too hot on the outside).
- Loam is not flammable, a loam wall 25 cm (10 inches) thick is considered fire-resistant.
- Loam is inexpensive, non-polluting, and a completely natural material
- Unlike lime and cement loam is not abrasive or irritating to skin.
- Loam must be protected continuously from penetrating humidity!
- Loam becomes firm when dried but will become pliant again when it becomes moist
- Loam is sensitive to frost when damp (construction planning should take this into account).
Where do I find loam?
Loam is a natural material and can be found in most parts of the world. It can even be obtained free if you know what to look for and can find an excavation where it is being removed.
Common sources are old loam pits, brickyards (raw bricks), from builders who specialize in natural materials. Sometimes bricklayers and furnace setters know where loam can be obtained. Landscaping suppliers frequently have loam as one of their soil choices.
