Prior to the invention of cement all buildings were built either in lime or mud mortar. Lime stone is the main source of the building lime. Lime has been used as the principal binder for mortars and plasters for the past 10,000 years. To undo the damage caused to historic buildings due to use of modern materials like cement, lime has been used in the conservation of all the monuments in the Qutb Shahi Heritage Park. Stucco Plaster is a key architectural element defining the architectural style of the Qutb Shahi’s. Over the years, the lime plaster has been replaced with cement in parts. Lime mortar is also required to carry out all masonry repairs.
- Samples of the existing lime mortar was collected from the monuments and sent for testing.
- Based on the test reports, samples of lime-stones were collected from various sources and tested to check the similarity.
- Similarly, river sand samples from sources up to a distance of 300 kms were collected and tested for similarity of fineness modulus, silt content and bulking.
- A mechanised lime grinding mill has been set up which can produce over 500 cubic feet of lime mortar in a day. Preparation of all lime mortar will be carried out under strict supervision at a single location as the preparation process is both specific and complex as compared to cement mortar which craftsmen are now used to working with.
- For adequate soaking of lime, six tanks were made to contain over 3000 cubic feet of lime.
- A centralised monitoring of lime mortar production has assured the quality of mortar in the restoration works. All necessary tests required for the final finish also have been carried out here.