The maximum gap for mortar in pointing should ideally be around 10 mm (approximately 0.4 inches).
While larger gaps might exist in older structures requiring repair, filling a gap significantly larger than 10 mm with mortar alone can lead to structural issues and cracking.
Here's a breakdown of considerations regarding mortar gap size:
- Ideal Range: 5mm - 10mm (approximately 0.2 - 0.4 inches) is the recommended range for mortar joints.
- Larger Gaps: Gaps significantly exceeding 10mm (0.4 inches) should be addressed differently, possibly requiring structural repair or a combination of techniques beyond simply filling with mortar. Using mortar to fill excessively large gaps can lead to:
- Cracking: The mortar may shrink and crack as it cures, especially in deep fills.
- Weakness: A large mass of mortar is more susceptible to movement and stress, potentially weakening the overall structure.
- Water Penetration: Cracks in large mortar fills provide pathways for water ingress, leading to further damage.
In summary, while gaps may vary depending on the structure and its age, a maximum mortar gap for pointing is ideally around 10mm (0.4 inches) to ensure structural integrity and prevent future problems. Larger gaps need to be addressed with more comprehensive solutions.
