journal
LIME PLASTER
Materials:
Slaked Lime , a mixture of lime and water, made to a paste like consistency
Sand
Aggregate
Surkhi*, burnt brick/mangalore tile powder
Guggul water*, Guggul is a plant, also known as Indian Bdellium. Guggul water is made by boiling 1kg of Guggul in dried form in 15litres of water.
Marble Powder*
Pigments* , oxide colours
* optional materials
Summary
There are different forms of Lime used in construction. We worked with Slaked Lime, which is obtained by combining quick lime (pure lime) with water. This quick lime is available as a powder form, in our experience we have found two sources of the quick lime in India. One is made by powdering Limestone, and the other by powdering seashells (available in coastal areas). The quick lime combines vigorously with water giving out heat, and is kept in this solution for at least a week, forming Slaked Lime.
We used lime plaster over the Laterite walls, a very traditional plastering material in Goa. The plaster is applied, in three layers- the Base coat, second layer and third/final layer.
The Base Layer is applied directly onto the masonry wall (brick, laterite, etc). Once the layer is dry, water is applied by splashing it over the wall. This is known as curing. The curing process is continued for over a week, every time the wall is dry, water is splashed onto the surface to keep it gently moist.
The frequency at which one applies the water, varies with the heat, and amount of moisture in the air. Thus, there is no standardised method for curing, and it varies from place to place and season to season.
After the curing is complete, the second and third layer are applied over two consecutive days.
base plaster
second layer
tools for applying
base plaster
tools needed for
second and final layers
base plaster
completed
final layer
Composition
Base Plaster Layer:
Lime, Sand, Aggregate and Surkhi (2:6:1:1).
With half a litre of the Guggul Solution.
The consistency of this mix should be like a smooth paste, when held with a trowel it shouldn’t drop very easily. Similar to the consistency of Slaked Lime.
Usual thickness of this layer is 12mm-15mm. (Also depend on the surface of the masonry wall)
The base coat is cured for roughly 1 week.
Once the cured surface is ready, we can apply the second coat. The wall surface is brushed with a thin mix of lime and water to prepare the surface for the second coat.
Second Layer:
Lime and Sand (1:3) and half litre of Guggul solution, colour oxide (if needed).
If one wants to add colour in the lime, this is the stage at which it is done. A drill can be used to mix it evenly.
The consistency of this layer is similar to that of yogurt, and it is applied 2-3mm thick.
The third layer/final layer is applied the next day after the second layer has dried.
Final coat: Lime and water, with 12% marble powder and colour oxide as required.
The consistency of this layer is thinner, much like milk and is applied 2-3mm thick.
* Note- before applying any layer, slightly wet the wall surface with either water or a thin mix of lime and water for better bonding.
related work:
