When installing wide reinforcing mesh fabrics on walls, how should seams be handled?

• A. Butt the edges with no overlap.
• B. Overlap by at least 100 mm.
• C. Overlap the edges by at least 50 mm (2 inches) to ensure continuous structural reinforcement.
• D. Overlap by at least 10 mm.

Answer: (C)

Continuity of reinforcement across seams is essential. When wide mesh fabrics are applied, the seam is a potential weak point where cracks can start if the mesh doesn’t carry stresses smoothly from one side to the other. Overlapping the edges allows fibers from both pieces to be embedded in the plaster or render, creating a continuous reinforcement path and enabling the coating to bond through the overlap. A 50 mm (2 inches) overlap provides enough material to grip and transfer tensile stresses without wasting material or causing finishing issues. Not overlapping would leave a weak seam, while too large an overlap (like 100 mm) is unnecessary and can complicate finishing, and too small an overlap (10 mm) may not be reliably captured by the plaster. So, overlap by at least 50 mm to ensure continuous structural reinforcement.