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IS 6042 : 1969Code of practice for construction of lightweight concrete block masonry

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BS EN 1996-2 · TMS 602-16 / ACI 530.1-16 / ASCE 6 · AS 3700
CurrentFrequently UsedCode of PracticeBIMStructural Engineering · Cement Matrix Products
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OverviewValues5InternationalTablesFAQ4Related

IS 6042:1969 is the Indian Standard (BIS) for construction of lightweight concrete block masonry. This code of practice details the requirements for the construction of masonry using lightweight concrete blocks. It covers the specifications for materials like blocks and mortar, workmanship for laying and jointing, and procedures for curing to ensure structural integrity and durability.

Code of practice for construction of lightweight concrete block masonry

Overview

Status
Current
Usage level
Frequently Used
Domain
Structural Engineering — Cement Matrix Products
Type
Code of Practice
International equivalents
BS EN 1996-2:2006 · British Standards Institution (BSI), UK / European Committee for Standardization (CEN), EuropeTMS 602-16 / ACI 530.1-16 / ASCE 6-16 · The Masonry Society (TMS) / American Concrete Institute (ACI) / American Society of Civil Engineers (ASCE), USAAS 3700:2018 · Standards Australia, AustraliaBS 8000-3:2020 · British Standards Institution (BSI), UK
Typically used with
IS 269IS 2116IS 1905
Also on InfraLens for IS 6042
5Key values1Tables4FAQs

BIM-relevant code. See the BIM Hub for ISO 19650, IFC, and LOD/LOIN frameworks used alongside it.

Practical Notes
! Ensure blocks are wetted before use but are surface-dry when laid to prevent rapid suction of water from mortar, which leads to poor bond strength.
! This is an older code; it is crucial to use it in conjunction with the latest versions of IS 2185 (for block specifications) and IS 1905 (for structural design).
! Maintaining a consistent mortar joint thickness, not exceeding 10 mm, is critical for uniform load distribution and achieving a good finish.
Frequently referenced clauses
Cl. 4MaterialsCl. 5.2MortarCl. 5.3Laying BlocksCl. 5.4JointingCl. 5.6Curing
Pulled from IS 6042:1969. Browse the full clause & table index below in Tables & Referenced Sections.
lightweight concreteconcrete blockmasonrymortarlightweight aggregates

International Equivalents

Similar International Standards
BS EN 1996-2:2006British Standards Institution (BSI), UK / European Committee for Standardization (CEN), Europe
HighCurrent
Eurocode 6: Design of masonry structures - Part 2: Design considerations, selection of materials and execution of masonry
Covers the execution (workmanship) and material selection for masonry, aligning with the practical focus of IS 6042.
TMS 602-16 / ACI 530.1-16 / ASCE 6-16The Masonry Society (TMS) / American Concrete Institute (ACI) / American Society of Civil Engineers (ASCE), USA
HighCurrent
Specification for Masonry Structures
Serves as the primary US specification for materials and construction of masonry, analogous to a code of practice.
AS 3700:2018Standards Australia, Australia
MediumCurrent
Masonry structures
Comprehensive standard covering both design and construction, with specific clauses on workmanship comparable to IS 6042.
BS 8000-3:2020British Standards Institution (BSI), UK
HighCurrent
Workmanship on construction sites. Masonry. Code of practice
Specifically a code of practice for masonry workmanship, making it a very direct functional equivalent to IS 6042.
Key Differences
≠IS 6042 is highly prescriptive, specifying exact mortar mix proportions (e.g., 1:1:6 cement:lime:sand). Modern international standards like TMS 602 and Eurocode 6 are performance-based, specifying mortar by strength class (e.g., M5) or type (e.g., Type N), allowing flexibility in achieving the required performance.
≠IS 6042 provides simple, fixed slenderness ratio limits (e.g., 12 for load-bearing walls). In contrast, Eurocode 6 and TMS 402/602 use more complex calculations for wall stability based on effective height, effective thickness, support conditions, and load eccentricity.
≠The Indian standard mandates a specific curing regime: keeping the masonry continuously moist for at least 7 days. International codes like TMS 602 focus on protecting masonry from weather extremes (freezing, rapid drying) but do not typically mandate a continuous multi-day wet cure.
≠IS 6042 is a standalone document with limited cross-referencing. Modern codes are part of a larger suite of standards (e.g., Eurocodes, ACI/ASCE/TMS series) that provide much more detailed, interlinked requirements for materials, testing, and design.
Key Similarities
≈All standards emphasize fundamental workmanship principles, including the need for full bed and head joints (unless otherwise specified), maintaining a consistent bond pattern, and keeping masonry units clean during laying.
≈The specified nominal mortar joint thickness is very similar across codes. IS 6042 specifies a maximum of 10 mm, while TMS 602 and BS EN 1996-2 specify a nominal 10 mm (or 3/8 inch), with defined tolerances.
≈The principle of bonding is consistent. IS 6042 requires a minimum lap of one-quarter of the block length, a rule that is closely mirrored in international standards to ensure load distribution and wall integrity.
≈All codes provide rules for cutting chases and holes for services. They place similar restrictions on the depth (typically 1/6 to 1/3 of the wall thickness) and spacing of chases to prevent compromising the wall's structural capacity.
Parameter Comparison
ParameterIS ValueInternationalSource
Nominal Mortar Joint ThicknessShall not exceed 10 mm10 mm (nominal); 3/8 in. (9.5 mm) (nominal)BS EN 1996-2 / TMS 602-16
Mortar Specification ApproachPrescriptive by proportion (e.g., 1:2:9 Cement:Lime:Sand)Performance-based by Type (M, S, N, O) or Strength Class (M12, M6, etc.)ASTM C270 (for TMS 602) / EN 998-2 (for EN 1996-2)
Curing RequirementKeep continuously moist for a period of not less than 7 days.Protect from freezing and rapid evaporation; maintain temperature above 4°C for 24-48 hours. No prescribed wet curing.TMS 602-16
Minimum Lap in Running BondAt least 1/4 of the block length.The greater of 0.4 x block height or 40 mm.BS EN 1996-2:2006
Slenderness Ratio Limit (Single Leaf Load-Bearing Wall)12 (Prescriptive limit)Calculated based on support conditions and eccentricity (e.g., can be up to 27), not a single prescriptive value.BS EN 1996-1-1
Vertical Chase Depth LimitMax 1/3 of wall thickness.Max 1/3 of wall thickness (unreinforced masonry).BS EN 1996-2:2006
⚠ Verify details from original standards before use

Key Values5

Quick Reference Values
Maximum mortar joint thickness10 mm
Minimum curing period for masonry7 days
Recommended mortar mix for general work (Cement:Sand)1:6 by volume
Minimum depth for raking joints for pointing15 mm
Maximum height of masonry to be built in a day1.5 m

Tables & Referenced Sections

Key Tables
Table 1 - Mortar Mixes
Key Clauses
Clause 4 - Materials
Clause 5.2 - Mortar
Clause 5.3 - Laying Blocks
Clause 5.4 - Jointing
Clause 5.6 - Curing

Related Resources on InfraLens

Cross-Referenced Codes
IS 269:2015Ordinary Portland Cement - Specification
→
IS 2116:1980Sand for masonry mortars - Specification
→
IS 1905:1987Code of Practice for Structural Safety of Bui...
→

Frequently Asked Questions4

What type of mortar is specified for lightweight blockwork?+
A cement-sand mortar. For general use, a mix of 1 part cement to 6 parts sand by volume is recommended (Table 1).
Do lightweight blocks need to be soaked before laying?+
The code requires blocks to be 'wetted thoroughly' but should be 'surface dry' when laid. This prevents them from absorbing too much water from the mortar (Clause 5.3.1).
What is the minimum curing period for lightweight block masonry?+
The masonry wall must be kept moist on all faces for at least 7 days after construction (Clause 5.6).
What is the maximum thickness for mortar joints?+
The thickness of both bed (horizontal) and butt (vertical) joints should be uniform and must not exceed 10 mm (Clause 5.4.1).

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