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IS 1127:1970 is the Indian Standard (BIS) for recommendations for dimensions and workmanship of natural building stones for masonry work. This code provides guidelines on standard dimensions and workmanship (dressing, squaring) for natural building stones used in masonry work. It helps ensure uniformity, proper bonding, and structural stability in stone masonry construction such as ashlar and rubble walls.
Recommendations for dimensions and workmanship of natural building stones for masonry work
! Always ensure the breadth of the stone is greater than or equal to its height to prevent instability and overturning within the masonry wall.
! Stones must be properly wetted before use in masonry to prevent them from absorbing moisture from the mortar.
! For actual construction practices and masonry bond details, refer to IS 1597 rather than this code, which is focused purely on the stone block sizing and dressing.
EN 1996-2:2006CEN (European Committee for Standardization), Europe
HighCurrent
Eurocode 6: Design of masonry structures - Part 2: Design considerations, selection of materials and execution of masonry
Covers workmanship, material selection, and execution for all masonry types, including natural stone.
TMS 602-16The Masonry Society, USA
HighCurrent
Specification for Masonry Structures
Provides specifications for materials and construction of masonry, including tolerances and workmanship for stone.
EN 771-6:2011+A1:2015CEN (European Committee for Standardization), Europe
MediumCurrent
Specification for masonry units - Part 6: Natural stone masonry units
Focuses on the properties and dimensional tolerances of the stone units themselves, a key component of IS 1127.
BS 5390:1976BSI (British Standards Institution), UK
HighWithdrawn
Code of practice for stone masonry
A direct historical equivalent covering workmanship and dimensional recommendations for stone masonry in the UK.
Key Differences
≠IS 1127 is highly prescriptive, providing fixed dimensions (e.g., minimum course height of 20 cm for ashlar). Modern codes like EN 1996-2 and TMS 602 are more performance-oriented, where dimensions are driven by architectural design and structural requirements.
≠IS 1127 defines specific traditional masonry types like 'Uncoursed Random Rubble' and 'Square Rubble Masonry'. International standards use a more generalized classification based on the degree of dressing and coursing.
≠IS 1127 is a standalone document for workmanship. In contrast, EN 1996-2 and TMS 602 are integrated parts of a comprehensive structural design framework, where workmanship tolerances are directly linked to design assumptions.
≠The Indian standard provides recommendations for hand-dressing of stones on-site (e.g., 'Beds shall be dressed...for a depth of at least 8 cm'), reflecting traditional practices. International standards focus more on tolerances for factory-produced units (per EN 771-6) and the final erected position.
Key Similarities
≈All standards emphasize the fundamental importance of full mortar joints for structural integrity and durability, requiring that bed and perpend joints be solidly filled.
≈The concept of using bond stones (or headers) to tie the withes of a thick wall together is a common requirement in IS 1127 and international standards for rubble or multi-wythe masonry.
≈Both IS 1127 and international standards recognize and specify requirements for different types of stone face finishes, such as fine-tooled, rough-tooled, and rock-faced.
≈All referenced standards specify permissible tolerances for the dimensions of the stone units and the finished masonry work, covering aspects like joint thickness, alignment, and plumb.
Parameter Comparison
Parameter
IS Value
International
Source
Bed Joint Thickness (Fine Ashlar)
Not exceeding 3 mm
1 mm to 3 mm (thin layer mortar joint)
EN 1996-2
Bed Joint Thickness (Rubble Masonry)
Not exceeding 20 mm
Typically 10-15 mm, but not explicitly capped at 20 mm; depends on unit regularity.
EN 1996-2
Minimum Course Height (Ashlar)
Not less than 20 cm
Not specified; determined by architectural design and the properties of the selected stone unit.
TMS 602 / EN 1996-2
Provision of Bond Stones (Rubble)
At least one bond stone per 0.5 m² of wall face area.
For multi-wythe stone masonry, at least one header for each 4.5 ft² (approx. 0.42 m²) of wall face.
TMS 602-16
Dimensional Tolerance (Height of Ashlar Unit)
± 1.5 mm
± 2 mm (Tolerance Class T2) or ± 1 mm (Tolerance Class T1)
EN 771-6
Projections on Rock-Faced Masonry
Projections beyond the nominal face shall not exceed 2.5 cm.
No specific value; governed by aesthetic requirements and specifications for the 'pitch line' or nominal face.
General practice in codes like TMS 602
⚠ Verify details from original standards before use
Key Values4
Quick Reference Values
Minimum breadth of stone blockNot less than the height of the stone
Maximum length of stone block3 times the height of the stone
Minimum height for ashlar masonry stones150 mm
Standard lengths of cut stone300, 450, 600, 750 mm
What is the recommended relationship between the length and height of a building stone?+
The length of the stone block should typically not exceed 3 times its height to ensure structural integrity and proper bonding.
What is the minimum breadth permitted for a building stone?+
The breadth at the bed of the stone should never be less than the height of the stone.
What is the difference between IS 1127 and IS 1129?+
IS 1127 provides recommendations for the dimensions and basic workmanship of stones for masonry, whereas IS 1129 specifically details the methods of dressing natural building stones.