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IS 2858:1984 is the Indian Standard (BIS) for roofing with mangalore tiles. This standard lays out the code of practice for roofing with clay roofing tiles of the Mangalore pattern over pitched roofs. It provides specific guidelines on the preparation of the timber framework, appropriate roof pitch, batten spacing, and the correct laying procedures for eaves, ridges, valleys, and hips to ensure durability and weatherproofing.
Code of practice for roofing with Mangalore tiles
Overview
Status
Current
Usage level
Specialized
Domain
Architectural — Building Construction Practices incl. Painting, Varnishing
BIM-relevant code. See the BIM Hub for ISO 19650, IFC, and LOD/LOIN frameworks used alongside it.
Practical Notes
! Always lay tiles starting from the eaves and work upwards towards the ridge.
! In areas subject to high winds or on very steep pitches, tiles must be securely tied to the battens using galvanized iron or copper wire through the provided holes.
! Special attention must be given to mortar pointing at ridges and hips to prevent water ingress without compromising ventilation.
BS 5534:2014+A2:2018BSI - British Standards Institution, UK
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AS 2050-2018Standards Australia, Australia
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TRI-016-2022Tile Roofing Industry Alliance, USA
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Fachregeln des ZVDHZVDH - Zentralverband des Deutschen Dachdeckerhandwerks, Germany
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Technical Rules for the German Roofing Trade
Comprehensive rules for all roofing aspects, with detailed sections on clay tile installation.
Key Differences
≠IS 2858 has minimal mechanical fixing requirements, suggesting nailing every fifth row and tying with wire. Modern international standards (like BS 5534) mandate extensive mechanical fixing (nails, clips, screws) for most or all tiles based on specific wind load calculations.
≠Underlay (sarking membrane) is not mandatory in IS 2858 and is considered for 'additional protection'. In BS 5534 and AS 2050, a correctly installed underlay is a mandatory and integral part of the roof system for secondary weather protection and condensation control.
≠IS 2858 provides prescriptive batten sizes based on support spacing. International codes often require batten sizes to be determined based on calculations considering tile weight, rafter spacing, and potential snow/wind loads.
≠Modern European codes often specify a counter-batten system (a second set of battens running up the slope) to create a clear ventilation and drainage path above the underlay. IS 2858 only details a single-batten system.
Key Similarities
≈All standards are built on the fundamental principle of overlapping tiles (headlap and sidelap) to ensure the roof sheds water effectively.
≈The basic laying procedure, starting from the eaves and working towards the ridge, is a common practice in IS 2858 and all international equivalents to ensure proper layering.
≈All codes recognize the critical importance of a minimum roof pitch for weather-tightness and provide guidance, acknowledging that lower pitches require more stringent waterproofing details.
≈The necessity of using special purpose-made tiles and fittings for ridges, hips, valleys, and verges is a common requirement across all standards to ensure a properly finished and weatherproof roof.
Parameter Comparison
Parameter
IS Value
International
Source
Minimum Recommended Roof Pitch
22.5 degrees (1 in 2.5). Steeper in areas of heavy rainfall.
Varies by tile profile; can be as low as 15° for some interlocking tiles with full underlay system, but generally 22.5° or more.
BS 5534
Tile Fixing (General Area)
Every fifth row of tiles nailed and alternate tiles in each row tied with 0.9 mm GI wire.
Fixing specification determined by wind load calculation. Often results in every tile being fixed with at least one nail or clip.
BS 5534
Underlay (Sarking)
Not mandatory. Can be used for 'extra protection' or on 'boarding'.
Mandatory. Must be a certified membrane (e.g., breathable) and properly installed.
AS 2050
Minimum Headlap
75 mm
75 mm (3 inches) minimum, but must be increased for lower roof pitches.
TRI-016
Batten Size (Typical)
50 x 25 mm for supports up to 750 mm; 75 x 40 mm for supports up to 1 m.
Typically 25 x 38 mm or 25 x 50 mm, but size is determined by span, tile weight, and load.
BS 5534
Batten Fixing
Nailed to common rafters with 75 mm to 100 mm long wire nails.
Must be fixed with nails (often galvanised ring shank) that penetrate at least 40 mm into the rafter.
AS 2050
⚠ Verify details from original standards before use
Key Values4
Quick Reference Values
Recommended minimum roof pitch30 degrees
Minimum overlap of tiles50 mm
Nominal spacing of battens310 mm to 340 mm (based on tile size)