Brickwork — standard modular size used in masonry (India) What is the standard size of a modular masonry brick (without mortar joint)?

Introduction / Context:
Standardization of brick size ensures uniform bonding, predictable mortar consumption, and reliable estimates. In Indian practice, the modular brick size is widely examined in construction materials courses and is fundamental to drafting wall details and calculating quantities.

Given Data / Assumptions:

• Modular brick size excludes mortar (dry size).
• Nominal dimensions with mortar differ by approximately 10 mm in length and width.
• All dimensions are in centimetres.

Concept / Approach:
For modular bricks, the standard dry size is 19 × 9 × 9 cm. When laid with a 10 mm mortar joint, the nominal size becomes 20 × 10 × 10 cm, aiding module-based design and coursing rules.

Step-by-Step Solution:
Recall the modular dry size used in IS specifications: 19 × 9 × 9 cm.Differentiate it from nominal size with mortar: 20 × 10 × 10 cm.Choose the correct dry (standard) size from the options.

Verification / Alternative check:
Brick coursing in elevation drawings confirms that adding a 10 mm joint yields the nominal module of 20 × 10 × 10 cm, matching design grids.

Why Other Options Are Wrong:
18 × 8 × 8 and 21 × 11 × 11 are non-standard. 20 × 10 × 10 cm corresponds to nominal size with mortar, not the dry modular brick size asked.

Common Pitfalls:
Mixing up dry and nominal sizes, leading to quantity errors in procurement and estimation.

Final Answer:
19 cm × 9 cm × 9 cm