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165 EXPLORATORY HOLES
• Requirement: Excavate holes to determine: site specific.
- Timing: Before commencing excavation for underpinning.
• Findings: Submit details.
• Backfill:
- Below foundation level: Concrete.
- Above foundation level but below ground supported slabs: Compacted hard
core.
- Elsewhere: Lean mix concrete.

170 DISCONNECTION OF SERVICES IN WORKING AREAS
• Disconnections required: site specific.
- Timing: Before commencing underpinning works within the building.
• Reconnection: Ensure that services cannot be reinstated by site operatives without
consent.

TYPES OF UNDERPINNING

210 CONTINUOUS MASS CONCRETE UNDERPINNING
• Underpinning blocks:
- Depth: site specific.
- Length (maximum): site specific.
- Width on either side of wall centre line (minimum): site specific.
- Depth of hard pack: Contractor's choice.
• Materials:
- Concrete: site specific.
- Hard packing: site specific.
Water content: Sufficient only to ensure that packing binds together.
• Sequence: To approval.
• Curing periods (minimum):
- Between casting underpinning block and pinning up: site specific.
- Between completion of pinning up and commencement of excavation for the
next sequence of underpinning: site specific.
Extend curing periods to allow for inclement weather.
• Shear connection between underpinning blocks: site specific.
• Features: site specific.

RotF generic (intermediate) NBS 2014 6118-AEW-XX-XX-NBS-A-01