Coir is a natural fibre from the outer husk of coconut, it serves as a highly effective and eco-friendly reinforcement fibre. It has a tensile strength similar to steel and forms a good structure thanks to its wiry nature.
Coir vs. Goat Hair
For lime plaster with lath and plaster walls, coir is an excellent substitute to natural goat hair. It has the strength and chemical composition to survive the extreme alkalinity of a lime plaster as it cures. It also offers several practical and economic advantages:
Coir is much cleaner and more pleasant to handle than natural animal hair.
Coir is much easier to handle and separate than goat hair which tends to clump and requires more effort to tease apart.
Coir can be mixed into lime plaster with a drill and paddle without becoming knotted around the tools as will a goat hair.
Coir will tend to distribute fairly evenly throughout the lime plaster when mixing with a drill and paddle whereas goat hair is added in layers to achieve an even distribution.
Coir has a higher tensile strength so much less is required, usage is typically half that of goat hair.
Adding to Lime Plaster
Coir is added to lime plaster base coat only, it is not added to the final finish coat. It is added after the plaster is mixed and just before it is applied to the wall.
Ratio of Coir / Lime Plaster
Approximately 1 gram of hair is required for each kilogram of lime plaster base coat.
- 250g (approx.)
- Will cover 250kg of material (approx.)