Path way to Lime Kilns

Indian Lime Revival – series 1

“Namma Lime Kilns” Lime stone cycle by Dheeraj Reddy – Namma means ‘Ours’

It’s a temple, right? The smoke must be from the ‘Aarti’ sessions, but wait why is it continuous? Nonstop ‘Aarti’ sessions? Kaunsa bagawan hai andhar ?(whose temple is it ?)
It’s a small ancient house, right? The smoke must be from the ‘choola’, but wait why is it continuous? They are probably cooking for many people, but how will so many fit in such a small house? Kitne compartments honge ismein..?(How many compartments it might have..?)
The above could be some of the perceptions of many among us at the first glance of the incredible ‘Lime kilns’, they are the Lime kilns that have been tirelessly supplying us the best lime through generations. But the role of lime has changed, (from being the crucial material in the construction as mortar to just being an external pre-coating), we no more see it in its true form, its strength (the very Lime kilns give us an account of it, standing firm, despite of being exposed to harsh climatic conditions). Not saying it’s lost, but it was our way of life with Lime kilns, there was a time where it was accessible to everyone, it wasn’t a “ mass production” but the lime kilns were everywhere and sometimes also in the backyards of individual homes. The glory isn’t lost, we can reintroduce them back into our lives into our homes, in this age of global warming they could be the saviours. It’s time we look back for a better future.
The production of lime is totally sustainable, it’s a cycle of life in a way, where the nature is not abused but embraced. The production involves the following steps,
i ) Lime stone Excavation (done from the nearby quarries in small quantities without the use of ‘explosives’)
ii ) Burning Limestone in the Lime kiln(yes the burning or calcining results in CO2 emissions but are negligible when compared to that of a cement production unit, also lime plaster during the setting period absorbs back the atmospheric CO2 )
iii) Hydration of Lime (Involves very less input of water and is the last step before the resultant powdered lime is packed and sent)
Thus lime production though a little laborious (because there are less “’machines” involved), the result is something the Lime maker is proud of, fine quality lime. The design of the Lime kilns doesn’t just abide by the factor of fuel efficiency, but also as per the comfort of the people involved and aesthetics that reflect the local culture, the following Lime kilns will relish you with their vernacularity ( in both material and design, adobe bricks, mud plaster and stone are most commonly used materials)

Below are the photos taken by Biju anna in his travels and researches in Indian villages talking to older people who worked with lime.

Dheeraj Annapureddy

This article is by Dheeraj Annapureddy, One of the founders of Natural Builders of India. This post is part of our Ageless Village series written by different people sharing their experience of a village, street or a single home. If you have an interesting story to tell and would like to share your experience with Thannal on our blog, please contact us!

Dheeraj AnnapureddyArchitect

Why use Lime by Stafford Holmes

1.The Use Of Lime Has Ecological Benefits

• Lime has less embodied energy than cement.
• Free lime absorbs carbon dioxide in the setting process of carbonation.
• It is possible to produce lime on a small scale.
• The gentle binding properties of lime enable full re-use of other materials.
• A very low proportion of quicklime will stabilize clay soils.
• Small quantities of lime can protect otherwise vulnerable, very low energy materials such as earth construction and straw bales.

2. Lime Provides A Comfortable Environment

Porous and open textured materials such as lime plasters, help to stabilize the internal humidity of a building by absorbing and releasing moisture. This makes for a more comfortable environment and reduces surface condensation and mould growth.
3. Lime Allows Buildings To Breathe
In the search by architects and conservators for building materials sympathetic to traditional construction, lime was found to be one of the most important. One of the reasons lime binders are promoted by the Society for the Protection of Ancient Buildings for repairs is because they are vapour permeable and allow buildings to breathe. This reduces the risk of trapped moisture and consequent damage to the building fabric.

4. Lime Binds Gently With Early Adhesion

The fine particle size of lime, far smaller than cement, is linked to the root meaning of the word lime, which is ‘sticky material’. Due to the fine particle size, lime mixes penetrate minute voids in the background more deeply than other materials. They bind gently and the stickiness gives good adhesion to other surfaces.
5. Lime Mortar Can Protect Adjacent Materials
Lime mortars with a high free lime content are porous and permeable. These characteristics allow lime mortars to protect adjacent materials by handling moisture movements through the building fabric and protecting them from harmful salts. Adjacent materials frequently affected this way include timber and iron as well as stone and brick masonry.

6. Lime Renders Can Assist Drying Out By Evaporation

Dense and impermeable renders can trap moisture within the building fabric. Trapped moisture is often the agent for various decay mechanisms. Dense renders used in conjunction with softer materials or on weaker backgrounds can cause serious problems by creating local stresses. High calcium lime renders allow evaporation and reduce the risk of trapped moisture and decay. In simple terms, the greater the extent of pure lime and permeability the better this is for the building. This needs to be balanced with durability, however, and some reduction in permeability may be necessary to obtain adequate weathering qualities, hence the advantage of feebly hydraulic limes for external use.
7. Lime Mixes Have Good Workability
The ability of a mortar or plaster to remain smooth and mouldable, even against the suction it may experience from porous building materials, is termed workability. Good workability greatly assists good workmanship, helping to achieve full joints with good bonding to the other materials. This is what makes lime based mixes such a pleasure to use. The workability provided by the lime allows the inclusion of widely graded and sharp aggregates in the mix. These enhance both the performance and the aesthetic of the finished work.

8. Lime Binders Can Be Durable And Have Stood The Test Of Time

When used carefully, lime is exceptionally durable. Caesar’s Tower at Warwick Castle has stood the test of time for over 600 years, and many cathedrals have stood longer. An outstanding example is the Pantheon Temple in Rome which has a lime concrete dome spanning over 43 metres (142 feet). This has survived for nearly 2000 years.
9. Lime Finishes Are Beautiful
The double refraction of light through calcite crystals give a unique aesthetic combining a soft texture with a lustre that has a liveliness and delight of its own. The graceful softness apparent in lime based materials is a visual indication of their intrinsic permeability, workability and soft binding properties. They can rapidly develop a rich patina which has a glowing translucent quality.

10. Lime Contributes To A Healthy Environment

Lime is caustic and has been extensively used, often in the form of limewash, for its disinfectant qualities. Lime is also used for water purification. Lime mortars, plasters, renders and limewash have been used to create hygienic surfaces and improve comfort conditions within buildings for thousands of years.
11. Self Healing
The nature of ground conditions and the elements are such that all buildings are subject to varying degrees of movement over time. When buildings made with lime are subject to small movements they are more likely to develop many fine cracks than the individual large cracks which occur in stiffer cement-bound buildings. Water penetration can dissolve the ‘free’ lime and transport it. As the water evaporates this lime is deposited and begins to heal the cracks. This process is called autogenous, or self healing.

12. Free Lime Encourages the Growth of Calcite Crystals

Calcite crystals are a different shape to those formed by the more complex compounds in hydraulic limes and cements. The crystals form in voids in lime rich environments. The growth of calcite crystals adds strength over time and generally provides a more open and permeable material than the denser eminently hydraulic and OPC mixes with little or no free lime.
13. Local Limes Enhance Regional Identity And Diversity
The diversity of limestone types provides variety and local distinctiveness. Different limes will vary in colour, texture and setting properties. Local limes have a regional identity, they give a sense of place and provide a continuous link with the local aesthetic. Local colour is the obvious example in respect of limewashes.

14. Disfiguring By Cement Can Be Avoided By The Use Of Lime

On site the temptation to use quick and easy solutions for short term gain can lead to long term problems. The attraction of using excess cement to be ‘safe’ is understandable if not desirable. The fact that it is plentiful, inexpensive and readily available adds to the problem. There is a high probability that over-strong and dense mixes that are not fit for purpose will be used in excess. The physical damage and unsightly aesthetic that results from this can be avoided by the use of lime.
15. Indefinite Shelf Life
Non-hydraulic limes have an indefinite shelf life when stored without access to air, usually as a putty under water or in sealed containers. In fact the quality of the putty improves the longer it is stored.
(This is an extract from An Introduction to Building Limes by Stafford Holmes, presented to the Foresight Lime research Conference at Manchester University on 19 November 2002 and revised March 2004.)

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