Roof framing components: the horizontal member provided to support common rafters in a sloping roof is known as which element?

Introduction / Context:
In timber or steel roof construction, rafters require intermediate horizontal supports to reduce span and provide fixing for roofing sheets or tiles. Correctly naming these members is important for drawings and BOQs.

Given Data / Assumptions:

• Member is horizontal and supports common rafters.
• Sloping roof system with rafters, purlins, battens/laths, cleats, and struts.

Concept / Approach:
A purlin is a horizontal beam spanning between trusses or walls, supporting the rafters. Battens (or laths) are smaller members fixed on rafters to carry tiles/slates. Cleats are small blocks/angles used for connections or to prevent slipping. Struts are compression members providing bracing, not primary horizontal supports for rafters.

Step-by-Step Solution:
Match function 'supports rafters' → purlin.Exclude battens (they sit on rafters), cleats (minor connectors), and struts (bracing).

Verification / Alternative check:
Standard roof framing diagrams label purlins directly beneath rafters, with battens above rafters carrying the roof covering.

Why Other Options Are Wrong:

• Batten: lighter, placed on rafters to fix tiles, not to support rafters.
• Cleat: a connector/support block, not a spanning member.
• Strut: compression brace, not a horizontal support to rafters.

Common Pitfalls:

• Confusing purlins and battens because both are horizontal; their size and position differ.

Final Answer:
purlin