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330 INSTALLATION OF WALL TIES GENERALLY
• Masonry:
- Stable at all times during wall tie installation.
- Formation of holes: Minimize.
- Cavities: Clear and free from debris.
- Fixing holes: Clean.
• Wall ties:
- Installation: Accurately and securely.
- Drips: Centred on cavity.
- Expansion anchor fixings: Set to the correct torque.
- Bonded fixings: Thoroughly grouted.
• Facework: Keep clean.
340 POSITIONING OF WALL TIES
• Spacing of wall ties: site specific .
• Additional ties:
- Reveals of unbonded openings and edges (including gables and movement
joints): Fix additional ties within 225 mm at 300 mm maximum vertical centres .
- Cavities with insulation batts: Beneath the lowest row of insulation batts .
350 REMOVING MASONRY UNITS FOR REUSE
• Removal of units: In one piece. Clean and set aside for reuse.
• Units unsuitable for reuse: Obtain instructions.
• Adjacent masonry:
- Joints: Do not damage or widen.
- Old mortar: Remove.
- Cavities: Keep clean.
355 REMOVING MASONRY UNITS
• Adjacent masonry:
- Joints: Do not damage or widen.
- Old mortar: Remove.
- Cavities: Keep clean.
360 CORE DRILLING MASONRY WITH RENDERED FINISH
• Drilling: Carefully and accurately to provide access to existing ties.
365 REMOVAL OF EXISTING WALL TIES FROM INTERNAL LEAF
• Wall ties: Remove carefully and completely.
• Internal leaf/ finishes: Minimize disturbance.
368 REMOVAL OF EXISTING WALL TIES FROM EXTERNAL LEAF
• Wall ties:
- Flexible wire ties: Crop or bend down against face of internal leaf.
- Rigid ties: Crop against face of internal leaf.
• Internal leaf/ finishes: Do not disturb.
370 MAKING GOOD OF CAVITY WALL INSULATION 6118-AEW-XX-XX-NBS-A-01
• Cavities: Clear of dirt and debris.
• New insulation: Agrément certified .
- Thickness: To match existing.
- Installation: Secure. No gaps.
RotF generic (intermediate) NBS 2014