Timber sections – naming by size for carpentry and building works A sawn piece of timber having thickness 5 cm (50 mm) and width 10 cm (100 mm) is called what?

Introduction:
Timber used in building construction is classified by its cross-sectional dimensions because different sizes imply different structural capacity and typical uses. The question checks your knowledge of standard carpentry terminology for sawn sections, especially the borderline case around 50 mm thickness and moderate width pieces.

Given Data / Assumptions:

• Thickness = 5 cm = 50 mm.
• Width = 10 cm = 100 mm.
• Terminology follows common building practice in Indian civil engineering and carpentry.

Concept / Approach:

Conventional terms are broadly: strip/batten for relatively narrow or thin pieces, board for thin but comparatively wide pieces, and plank for thicker, wider members. Many handbooks consider pieces at or above about 50 mm thickness and of moderate width to fall under “plank.”

Step-by-Step Solution:

Verification / Alternative check:

Many standard references group pieces thinner than about 50 mm and narrow in width as strips/battens; boards are usually thinner than 50 mm but relatively wide. The 50 mm thickness pushes this piece into the plank category rather than a board.

Why Other Options Are Wrong:

Slate: Slate is a stone product, not timber, so the term is irrelevant.
Board: Typically thinner (< 50 mm) and often wider than 100 mm; thickness here is on the plank side.
Strip: Used for narrow/thin pieces, generally smaller than this section in both thickness and width.

Common Pitfalls:

Memorizing only one dimension. Names depend on both thickness and width; the 50 mm thickness is decisive here.

Final Answer:

Plank