When are mechanical cramps required for wall coverings?

They are required for heavy cladding materials like stone or marble, especially on exterior facades or at heights, to safely transfer the load to the backing wall.

What is the recommended mortar mix for fixing stone wall coverings?

Typically a cement-sand mortar ratio of 1:3 or 1:4 is used, depending on the weight and type of the covering material.

What material should be used for cramps and dowels?

Non-corrosive materials such as copper, gunmetal, or stainless steel to prevent rusting and subsequent spalling of the cladding.

IS 1414

: 1989

Code of practice for fixing wall coverings

CurrentSpecializedCode of PracticeArchitectural · Building Construction Practices incl. Painting, Varnishing

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This code covers the methods and practices for fixing various types of wall coverings (like stone, marble, and tiles) to interior and exterior building walls. It details surface preparation, mortar mix proportions, and the essential use of mechanical fasteners such as cramps and dowels to ensure safety and durability.

Code of practice for fixing wall coverings

Quick Reference Values

thickness of mortar bed12 mm to 15 mm typically

depth of raking joints in background13 mm

typical mortar proportion1:3 or 1:4 (Cement:Sand)

Practical Notes

Heavy stone or marble cladding must never rely entirely on mortar adhesion; mechanical fixings (cramps/dowels) are mandatory to prevent delamination and falling.

Always use non-corrosive metals (like copper, gunmetal, or stainless steel) for cramps and dowels to prevent rust, which expands and causes stone spalling and staining.

The background masonry or concrete must be properly roughened, cleaned, and wetted before applying the mortar bed to ensure a strong bond.