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IS 3036:1992 is the Indian Standard (BIS) for laying lime concrete for a waterproofed roof finish. This code provides guidelines for the preparation, laying, beating, and curing of lime concrete to create a waterproof finish on flat roofs. It details traditional terrace waterproofing methods frequently used in regional construction and heritage building restoration.
Code of practice for laying lime concrete for a waterproofed roof finish
BS 7913:2013BSI - British Standards Institution, UK
LowCurrent
Guide to the conservation of historic buildings
Provides principles for using traditional materials like lime, but is not a prescriptive code for this specific roofing application.
EN 459-1:2015CEN - European Committee for Standardization, Europe
LowCurrent
Building lime - Part 1: Definitions, specifications and conformity criteria
Specifies the properties of the lime binder itself, not the code of practice for its application as a roofing material.
ASTM C270-19aASTM International, USA
LowCurrent
Standard Specification for Mortar for Unit Masonry
Specifies properties for lime-based mortars (Type O, K, N, L), sharing material principles but not the roofing application.
Key Differences
≠IS 3036 describes a monolithic waterproofing system where the lime concrete itself provides the water barrier. Modern international standards mandate a separate, dedicated waterproofing layer (e.g., bituminous, synthetic membrane).
≠The Indian standard is a prescriptive 'code of practice' detailing the 'how-to' of laying and finishing. Most equivalent international standards are either material specifications (like EN 459-1) or performance-based guides, leaving the method to the designer.
≠IS 3036 specifies a unique final finishing process of 'beating' and 'polishing' with a lime mortar grout to create a dense, water-repellent skin. This technique is not found in modern international roofing standards.
≠The Indian standard relies on traditional, often locally sourced aggregates like brick 'jhama' ballast. International standards for concrete or screeds specify aggregates with rigorously defined properties (grading, strength, cleanliness) as per standards like EN 12620 or ASTM C33.
Key Similarities
≈Both IS 3036 and modern roofing codes universally require the substrate to be laid to a sufficient slope to ensure positive drainage of rainwater.
≈The principle of proper and extended curing is critical in both. IS 3036 mandates at least 10 days of wet curing, which aligns with the universal need for curing any cementitious or lime-based material to achieve desired durability and minimize cracking.
≈Emphasis is placed on the quality of constituent materials. While methods differ (field tests in IS vs. lab certification in EN/ASTM), both systems acknowledge that binder, aggregate, and water quality are fundamental to performance.
≈Substrate preparation is a key step in both. IS 3036 requires a clean base course, similar to how modern standards require a clean, dry, and stable deck or screed before applying subsequent layers.
Parameter Comparison
Parameter
IS Value
International
Source
Primary Binder Type
Class B (semi-hydraulic) or Class C (fat lime) as per IS 712
Natural Hydraulic Lime (NHL 2, NHL 3.5, NHL 5) or Calcium Lime (CL)
EN 459-1:2015
Minimum Roof Gradient
Laid to required slope (typically 1 in 60 to 1 in 40 in practice)
Minimum designed fall of 1:40 for flat roofs to achieve a finished fall of 1:80
BS 6229:2018
Minimum Finished Thickness
100 mm average; 75 mm at any point
Not comparable. Modern waterproofing is a thin membrane (1-5mm); screed thickness is designed separately.
N/A (fundamentally different system)
Curing Requirement
Kept continuously wet for a minimum of 10 days after laying.
No single value. For hydraulic lime, protection from rapid drying is critical for weeks; not prescriptive on water application.
Guidance based on BS 7913:2013
Coarse Aggregate Type
Over-burnt brick ballast (20 mm nominal size) or broken stone.
Not specified for this application. General concrete standards require well-graded stone/gravel meeting specific criteria (e.g., EN 12620).
N/A
Final Surface Finish
Beating and polishing with lime mortar grout.
Not applicable. The finish is the waterproofing membrane itself or a protective overlay like gravel or paving.
N/A (fundamentally different system)
⚠ Verify details from original standards before use