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IS 4920:1968 is the Indian Standard (BIS) for glossary of terms applicable to roof coverings. This standard provides a comprehensive glossary of terms related to various types of roof coverings used in building construction. It standardizes the vocabulary for pitched and flat roofing systems to ensure clarity in drawings, specifications, and contracts.
Glossary of terms applicable to roof coverings
Overview
Status
Current
Usage level
Rare
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
! Highly useful for specification writers and quantity surveyors to maintain consistent terminology in BOQs (Bill of Quantities).
! Helps prevent contractual disputes arising from ambiguous descriptions of architectural roofing components like eaves, flashing, ridge, and soffit.
! BIM managers can use this terminology for naming conventions and parameter descriptions for roof families.
roofing materialstilessheetingbitumenfelt
International Equivalents
Similar International Standards
ASTM D1079-22ASTM International, USA
HighCurrent
Standard Terminology Relating to Roofing and Waterproofing
Provides a comprehensive glossary of terms for roofing, very similar in purpose to IS 4920.
ISO 6707-1:2020International Organization for Standardization (ISO), International
MediumCurrent
Buildings and civil engineering works — Vocabulary — Part 1: General terms
A broad vocabulary standard for construction, containing many fundamental roofing terms but not focused solely on roofing.
BS 5534:2014+A2:2018British Standards Institution (BSI), UK
LowCurrent
Slating and tiling for pitched roofs - Code of practice
A code of practice, not a glossary, but its 'Terms and definitions' section serves as a modern vocabulary for a specific roofing type.
BS 6100-1.5:1986British Standards Institution (BSI), UK
HighWithdrawn
Glossary of building and civil engineering terms. Coverings and claddings
A direct historical equivalent, being a glossary specifically for roof coverings, though now obsolete.
Key Differences
≠IS 4920:1968 is significantly outdated and lacks definitions for modern materials like synthetic membranes (EPDM, TPO), liquid-applied roofing, green roof components, and advanced underlayments, which are extensively covered in ASTM D1079.
≠The Indian standard includes terms for materials and styles specific to the subcontinent, such as 'Allahabad tiles', 'Mangalore tiles', and 'Jalli', which have no direct equivalent in international standards.
≠Modern international standards like ASTM D1079 are structured to support a system of performance-based test methods, with definitions often referencing these tests. IS 4920 provides purely descriptive, qualitative definitions.
≠IS 4920 is a standalone glossary. In contrast, European (EN) standards typically embed definitions within specific product or execution standards (e.g., a standard for metal roofing will define terms relevant only to that system).
Key Similarities
≈Fundamental geometrical and component terms such as 'Ridge', 'Hip', 'Valley', 'Eaves', and 'Gable' are defined with very similar meanings across both IS 4920 and all international equivalents, reflecting universal roofing principles.
≈The primary purpose of all standards is to establish a common, unambiguous vocabulary for stakeholders (designers, contractors, manufacturers) to avoid miscommunication.
≈Definitions for traditional materials like slate, clay tiles, and bitumen (asphalt) are present in both the Indian and international standards, acknowledging their long history in roofing.
≈All standards define the concept of 'Flashing' as a material or component used to weatherproof junctions and joints, recognizing its critical role in roof integrity.
Parameter Comparison
Parameter
IS Value
International
Source
Pitch
The angle of inclination of a roof to the horizontal.
The angle of a roof to the horizontal, expressed as a ratio of the vertical rise to the horizontal run (in./ft) or as the tangent of the angle.
ASTM D1079-22
Flashing
A strip of impervious material, usually metal, used to cover a joint exposed to the weather.
A component used to waterproof or weatherproof the junctions, and joints, at perimeters, penetrations, walls, expansion joints, valleys, drains...
ASTM D1079-22
Sarking Felt
A felt used underneath roof covering.
(Referred as Underlayment) A material that is applied to the roof deck before the installation of the primary roof covering.
ASTM D1079-22
Ridge
The apex of the angle formed by two inclined roof surfaces.
Highest horizontal or inclined intersection of two sloping roof surfaces.
ISO 6707-1:2020
Eaves
The lower edge of a sloping roof projecting beyond the face of the wall below.
Lower edge of a roof, which usually projects beyond the line of the outside wall.
ISO 6707-1:2020
Battens
Pieces of timber of small section to which tiles or slates are fixed.
A member fixed to the rafters, to which slates or tiles are attached.
BS 5534:2014+A2:2018
Valley
The re-entrant angle formed by the intersection of two inclined roof surfaces.
Internal angle formed by the intersection of two sloping roof surfaces, down which water flows.
ISO 6707-1:2020
⚠ Verify details from original standards before use
Key Values0
No quick reference values available for this code yet.
Tables & Referenced Sections
Key Tables
No tables data
Key Clauses
No clauses data
Frequently Asked Questions3
Does IS 4920 provide specifications or tests for roofing materials?+
No, it is strictly a glossary of terms and definitions. Specifications are covered in material-specific codes.
Are both flat and pitched roofs included?+
Yes, the standard covers terminology applicable to both pitched roof and flat roof coverings.
Who benefits most from this code?+
Architects, specification writers, and quantity surveyors who draft technical and contract documents.