Brick Anatomy – Usual Location of the Frog on a Standard Brick Considering how bricks are moulded and the purpose of the mortar key, on which face of a standard brick is the frog (the rectangular depression) normally provided?

Introduction:
Knowing where the frog is provided helps masons orient bricks correctly, ensuring adequate mortar reception and bed thickness. Orientation of frogs affects bond, uniformity, and finish in brick masonry courses.

Given Data / Assumptions:

• A frog is a rectangular depression moulded into a brick.
• It is typically formed on one of the large faces during moulding.
• Purpose: to receive mortar and improve mechanical keying in the bed joint.

Concept / Approach:

Since mortar is spread on bed faces, forming the frog on a large (top) face provides a recess for mortar. This increases contact area and bond, reduces slippage, and helps control the effective thickness of the bed joint for structural and aesthetic quality.

Step-by-Step Solution:

Verification / Alternative check:

Construction handbooks illustrate the frog on the large bed face, with guidance on its orientation while laying courses depending on detailing.

Why Other Options Are Wrong:

Bottom face only is not the normal provision; stretcher/header sides are narrow faces and not used for frog formation; it is not provided on all faces.

Common Pitfalls:

Assuming location is arbitrary; confusing placement guidance during laying with manufacturing location.

Final Answer:

Top face (one of the large bed faces)