What is the standard pitch and depth for corrugated AC sheets?

The standard pitch is 146 mm and the depth of corrugation is 48 mm.

What is the typical thickness of AC roofing sheets specified in this code?

The standard nominal thickness for general roofing applications is 6 mm.

How is the water-tightness of the sheet tested?

By conducting an impermeability test where a tube is sealed to the sheet surface, filled with water to a specified height, and checked for wetness at the bottom after 24 hours.

IS 459

: 1992

Corrugated and semi-corrugated asbestos cement sheets

CurrentSpecializedSpecificationMaterials Science · Roofing Materials

Download PDF BIS Portal Google

This standard lays down the requirements regarding composition, dimensions, and physical properties (like load-bearing capacity and impermeability) for corrugated and semi-corrugated asbestos cement sheets used primarily for roofing and cladding.

Specifies requirements for corrugated and semi-corrugated asbestos cement sheets for roofing and cladding.

Quick Reference Values

Standard overall width (Corrugated)1050 mm

Pitch of corrugation146 mm

Depth of corrugation48 mm

Standard nominal thickness6 mm

Tolerance on length± 10 mm

Tolerance on thickness± 0.5 mm

Practical Notes

Always use cat ladders or roof crawl boards when working on AC sheet roofs; never walk directly on them as they are brittle and cannot sustain concentrated point loads.

Appropriate health and safety precautions (such as P3 masks) must be taken during cutting, drilling, and handling to avoid asbestos dust inhalation.

Ensure proper end and side laps as specified in IS 3007 during installation to prevent water leakage and uplift during high winds.