Ashlar Masonry – Joint thickness limit for finely dressed work In which type of ashlar masonry are stones finely chisel-dressed so that the thickness of joints does not exceed about 3 mm?

Introduction / Context:
Ashlar masonry involves precision-dressed stones laid with very thin joints for strength and appearance. Recognizing types helps in specifying quality, cost, and craftsmanship for façade and structural masonry work.

Given Data / Assumptions:

• Stones are finely chisel-dressed on beds and joints.
• Joint thickness is very small, about 3 mm.
• Regular, horizontal courses are intended.

Concept / Approach:
In coursed ashlar masonry, stones are cut to uniform height and laid in regular courses with very fine joints, typically limited to a few millimetres (about 3 mm). Other types either allow irregular coursing, thicker joints, or textured faces.

Step-by-Step Solution:
Match the requirement of very thin joints with finest dressing.Identify the form with regular, even courses: coursed ashlar.Exclude types that imply irregularity or special face treatments.

Verification / Alternative check:
Standard specifications list joint thickness limits and dressing levels; coursed ashlar consistently targets the thinnest, most accurate joints for premium work.

Why Other Options Are Wrong:

• Random coursed ashlar: irregular course heights and generally thicker joints.
• Ashlar facing: a veneer over rubble backing; joint control depends on backing and is not necessarily 3 mm.
• Chamfered/pitched faced: face treatments that do not define the thinnest joint specification.

Common Pitfalls:
Assuming any ashlar implies the same joint thickness; actual limits vary by type and specification.

Final Answer:
Coursed ashlar masonry