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IS 2394:1984 is the Indian Standard (BIS) for the application of lime plaster finish. This code establishes the guidelines and procedures for the application of lime plaster finishes to internal and external building surfaces. It details background preparation, material selection, mix proportioning, and techniques for single and multi-coat plaster applications.
Code of practice for the application of lime plaster finish
Overview
Status
Current
Usage level
Specialized
Domain
Architectural — Flooring, Wall Finishing and Roofing
! Proper slaking of quicklime (as per IS 1635) and adequate aging of lime putty is crucial to prevent popping, pitting, and blistering in the finished plaster.
! Adequate drying and partial carbonation time must be allowed between successive coats.
! Background surfaces must be properly roughened (raking of masonry joints) and thoroughly wetted to ensure mechanical key and proper bond without sucking moisture from the fresh plaster.
BS EN 13914-2:2016BSI / CEN (British Standards Institution / European Committee for Standardization), UK / EU
HighCurrent
Design, preparation and application of external rendering and internal plastering. Internal plastering
Covers the application of internal plasters, including lime-based systems, on various backgrounds.
ASTM C926 - 19ASTM International, USA
MediumCurrent
Standard Specification for Application of Portland Cement-Based Plaster
While focused on cement plaster, it details the three-coat application process and allows lime addition, making the methodology comparable.
BS 5262:1991BSI (British Standards Institution), UK
HighWithdrawn
Code of practice for external renderings and internal plastering
A comprehensive code of practice very similar in structure and intent to IS 2394, covering traditional plaster mixes and application.
DIN 18550-2:2019-07DIN (Deutsches Institut für Normung), Germany
MediumCurrent
Plaster and plastering systems - Part 2: Plaster made from premixed plaster masonry mortars
Covers execution of plastering, including systems that can be lime-based, but is heavily focused on modern pre-mixed mortars.
Key Differences
≠IS 2394 is exclusively for lime plaster, whereas modern standards like BS EN 13914 cover a broader range of binders including gypsum, cement, and polymer-modified systems.
≠IS 2394 provides prescriptive mix proportions (e.g., 1 lime: 2 sand). In contrast, EN standards are largely performance-based, specifying the required properties of the hardened plaster rather than the mix recipe, especially for proprietary products.
≠The Indian standard focuses on traditional materials (lime, sand, surkhi). International counterparts like ASTM C926 and EN 13914 incorporate guidance for modern chemical admixtures (e.g., air-entrainers, plasticizers) and mesh reinforcements.
≠IS 2394 specifies a rigid curing regimen of keeping the surface damp for at least 7 days. BS EN 13914 is more flexible, advising protection from rapid drying with methods and duration dependent on the type of lime (hydraulic vs. non-hydraulic) and site conditions.
Key Similarities
≈The fundamental principle of a multi-coat system (e.g., scratch coat, floating/brown coat, and finishing coat) is a common methodology described in IS 2394, ASTM C926, and BS EN 13914.
≈All standards place strong emphasis on the proper preparation of the background surface, requiring it to be clean, free of loose material, and having adequate key or suction for adhesion.
≈The recommended total thickness of the plaster system is broadly similar across the standards, typically falling within the 15-25 mm range for a traditional two or three-coat application on masonry.
≈All codes of practice mandate a waiting period between the application of successive coats to allow for initial set, partial drying, and shrinkage control, preventing cracking of the subsequent layer.
Parameter Comparison
Parameter
IS Value
International
Source
Total Plaster Thickness (Typical)
15-20 mm for two-coat work on masonry.
Nominal 13-20 mm for internal two-coat work (undercoat + finish).
BS EN 13914-2:2016
Undercoat Thickness (Single Layer)
10 to 12 mm.
First (scratch) coat nominal 10 mm (3/8 in); second (brown) coat nominal 10 mm (3/8 in).
ASTM C926 - 19
Finish Coat Thickness
3 to 8 mm depending on the number of undercoats.
2 to 5 mm for a smooth finish.
BS EN 13914-2:2016
Curing Period
Keep surface damp for at least 7 days.
Protect from premature drying; light spraying may be required for several days. Duration depends on lime type and exposure.
BS EN 13914-1:2016
Undercoat Mix Proportion (Lime:Sand)
1 : 2 to 1 : 3 (by volume).
Not prescribed; performance-based. A traditional equivalent mix for hydraulic lime (NHL 3.5) is typically 1 : 2.5.
BS EN 13914-2:2016 / General Practice
Time Between Coats
2 to 3 days for undercoats to dry.
Not specified in days; preceding coat must be sufficiently firm and hard to receive the next coat without damage.
ASTM C926 - 19
Background Preparation (Masonry Joints)
Joints shall be raked out to a depth of at least 10 mm.
Joints should be raked out to provide a key; a depth of 10-15 mm is recommended.
BS EN 13914-1:2016
⚠ Verify details from original standards before use