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).

IS 6042

: 1969

Code of practice for construction of lightweight concrete block masonry

CurrentFrequently UsedCode of PracticeBIMStructural Engineering · Cement Matrix Products

Download PDF BIS Portal Google

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

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

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.