IS 12093:1987 is the Indian Standard (BIS) for laying and fixing sloped roof coverings using plain and corrugated galvanized steel sheets. This standard outlines the code of practice for laying and fixing sloped roof coverings using plain and corrugated galvanized steel sheets. It provides guidance on materials, supporting framework, laying procedures, fixing methods, and weatherproofing details like ridges and gutters. The primary objective is to ensure the roof is structurally sound, weather-resistant, and durable.
Code of practice for laying and fixing sloped roof coverings using plain and corrugated galvanized steel sheets
BIM-relevant code. See the BIM Hub for ISO 19650, IFC, and LOD/LOIN frameworks used alongside it.
| Parameter | IS Value | International | Source |
|---|---|---|---|
| Minimum End Lap | 150 mm | 150 mm for slopes >15°; increases for lower slopes | AS/NZS 1562.1:2018 |
| Minimum Side Lap | One and a half corrugations | One corrugation (standard); Two corrugations for low slopes or severe exposure | BS 5427:2016 |
| Primary Fastener Type | 8 mm galvanized J-bolts or L-hooks | Hex-head, self-drilling screws with bonded EPDM washers | The NRCA Roofing Manual |
| Purlin Spacing | Prescriptive, e.g., 1.6 m for 0.63 mm sheet | Performance-based; calculated based on design loads, sheet profile, and material strength. | AS/NZS 1562.1:2018 |
| Fastener Location on Profile | Through the crown of the corrugation | Always through the crest (crown) for roof applications | The NRCA Roofing Manual |
| Lap Fastening | 6 mm hot-dip galvanized rivets | Stitching screws (typically smaller gauge self-drilling screws) | MBMA Metal Roofing Systems Design Manual |
| Minimum Recommended Roof Slope | Not explicitly stated, but practice implies >10 degrees | ~5 degrees (1:12) for exposed fastener panels, often with sealant in laps | MBMA Metal Roofing Systems Design Manual |