Conflicting Wall Elevations During Construction
During construction of a hillside neighborhood park, a field observation reveals a conflict in the construction documents. The retaining wall detail shows the top of wall at elevation 108.5, while the grading plan spot elevation at the same location is 108.2. The wall retains an accessible walkway with a 2% cross slope and a 4-foot-high guardrail. The contractor has already poured the footing for a 90-foot section and has submitted an RFI asking to 'field-fit' the wall down 3 inches. The landscape architect's last site visit was 10 days ago, and the contractor is requesting approval of a pay application that includes 100% of the wall footing. The owner's representative wants to avoid a change order and asks whether the 3-inch difference matters.
1. What is the significance of the 3-inch discrepancy, and what should the landscape architect do first?
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A 3-in conflict is not automatically trivial; evaluate what it controls.
- Determine which document governs. The wall detail and grading plan serve different purposes: the detail sets wall geometry and guardrail height; the grading plan sets walkway elevation and drainage.
- A 3-in lowering can affect the walkway cross slope, the guardrail height above the walking surface, the wall footing embedment, and the drainage swale at the wall base.
- Do not approve a field-fit by RFI. Request the contractor's survey of the footing as built, the structural engineer's review, and a revised section showing the walkway, guardrail, and drainage.
- If the footing is already placed, the designer must confirm whether the wall can be lowered without reducing embedment or changing the guardrail. A field-fit may be acceptable only with a written ASI and revised detail.
2. How should the pay application be handled?
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Certify only work that is in place and not in dispute.
- The footing may be physically in place, but if its elevation is tied to the unresolved wall conflict, the landscape architect should not certify 100% of that item.
- Review the pay application against the schedule of values; withhold the portion affected by the RFI until the ASI is issued.
- Do not use payment as a threat, but do not certify work that may require removal. Document the reason for the partial certification.
- If the footing is unaffected by the 3-in wall adjustment, certify it and withhold only the wall stem or related work. The key is a written record of what was accepted and why.
3. What documentation should be issued, and who bears the cost?
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Issue a written clarification and allocate cost based on the contract documents.
- If the contractor built the footing at the elevation shown on the approved drawings, and the drawings conflict, the owner bears the cost of the clarification through a change order.
- If the contractor deviated from the drawings or failed to request clarification before placing concrete, the contractor bears the cost.
- Issue an ASI with a revised wall section, walkway elevation, guardrail height, and drainage detail. Require the contractor to submit a cost proposal before proceeding.
- Record the as-built condition and include the resolution in the closeout documents. A field-fit without a written directive leaves the owner with an unallocated risk.