Requests for Information are often treated as a normal cost of doing business on curtain wall projects. They are not. An RFI is a symptom of a coordination failure that happened earlier in the process — in design, in documentation, or in the handoff between disciplines. By the time an RFI hits the field, the cost of resolution is already significantly higher than it would have been if the conflict had been caught at the source.
Curtain wall consistently generates more RFIs than most other building systems. This is not a coincidence. The combination of tight tolerances, multi-trade interfaces, complex geometry, and long lead times creates a concentrated set of conditions where documentation gaps surface quickly and painfully.
Understanding why these RFIs happen — and where in the process they originate — is the first step toward reducing them.
RFIs Are a Coordination Problem, Not a Field Problem
The instinct is to treat RFIs as a construction-phase issue managed by the GC and facade contractor. In practice, most curtain wall RFIs trace back to decisions — or the absence of decisions — made during schematic design, design development, or the coordination drawing phase.
A field crew asking for clarification on anchor location is not creating the problem. They are discovering a conflict that was built into the documentation weeks or months earlier. Resolving it at that point requires engineering review, potential redesign, subcontractor coordination, and sometimes remobilization. The labor cost of the RFI process itself — writing, reviewing, responding, distributing — is substantial before any physical work begins.
The path to fewer RFIs runs through better early documentation, not faster RFI response.
The Five Main Causes of Curtain Wall RFIs
1. Incomplete or Uncoordinated Documentation
Curtain wall documentation packages are extensive: anchor layouts, panel schedules, glazing schedules, spandrel details, thermal barrier details, perimeter seal conditions, and corner conditions all need to be coordinated and internally consistent. When these documents are developed in isolation — the architect producing elevations, the facade consultant producing shop drawings, the structural engineer producing embed details — gaps appear at every interface.
Common documentation gaps include: anchor locations not reconciled with slab edge geometry; panel dimensions that don't account for mullion profile depth; glazing specifications that reference discontinued product lines; and corner panel details that don't match the system logic of the field units.
These gaps are invisible in the documents individually. They only become visible when the documents are read together — which often happens on site.
2. Panel Geometry That Conflicts with the Structural Frame
The interface between the curtain wall system and the structural frame — specifically the slab edge and embed plate locations — is one of the highest-density coordination zones on any curtain wall project. The curtain wall frame must fit within the anchor zone, clear the slab soffit, allow for thermal breaks, and maintain the required exterior face dimension.
When structural slab geometry is modeled at low detail early in design and then updated later, curtain wall anchor layouts based on the earlier model become incorrect. Embed locations shift. Slab edge profiles change. These changes cascade into anchor redesign, which may require revised shop drawings and re-engineering of the anchor hardware — all of which generate RFIs when the conflicts surface during installation.
3. Facade-MEP Conflicts at the Perimeter
The curtain wall perimeter zone is also where perimeter heating units, ceiling grid terminations, soffit conditions, and mechanical penetrations compete for space. These conflicts are difficult to see in plan or section alone — they require 3D coordination to identify reliably.
When facade and MEP design are coordinated late — or not coordinated at all before construction documents are issued — the conflicts become RFIs. Perimeter heating units that don't fit within the spandrel zone. Ceiling heights that cut across the curtain wall frame. Penetrations that were not included in the curtain wall anchor layout.
These conflicts are entirely preventable with early coordination, but they require all trades to have sufficiently developed models at the same time — a coordination challenge in itself.
4. Late Design Changes That Cascade Through Coordinated Drawings
Curtain wall documentation is highly interdependent. A change to panel width affects the grid layout, which affects anchor spacing, which affects embed locations, which affects the structural engineer's drawings. A change to spandrel height affects the panel schedule, the glazing schedule, and potentially the thermal performance calculations.
When design changes occur after coordination is underway — which is common on projects where design and construction timelines overlap — the cascade effect multiplies the documentation effort. If the model is not parametric, every downstream document must be updated manually. Manual updates introduce inconsistencies. Inconsistencies generate RFIs.
Late changes are sometimes unavoidable. But the cost of a late change is directly proportional to how far downstream the coordination has progressed when the change is made. A change in schematic design costs very little. The same change during shop drawing review can cost orders of magnitude more.
5. Tolerance Mismatches Between Structure and Curtain Wall
Structural concrete is built to tolerances of approximately ±25 mm for column and slab positioning, per standard construction practice. Curtain wall systems are fabricated to tolerances of ±6 to ±12 mm. This gap is not a defect — it is an inherent condition that must be explicitly accommodated in the anchor design.
When anchor designs do not provide sufficient adjustment range, or when the allowable adjustment is consumed by other variables (concrete finish thickness, thermal break dimensions, vapor barrier), the installed structure falls outside the range the curtain wall system can accommodate. This results in RFIs, field modifications, or both.
Tolerance analysis is straightforward engineering, but it requires that the anchor design and the structural model be developed together — not independently and reconciled later.
What RFIs Actually Cost
RFI volume is often tracked as a project health metric, but the actual cost of an RFI on a curtain wall project goes well beyond the administrative time to write and respond.
A single structural conflict on a curtain wall anchor — the kind that generates a standard RFI — can require: a site survey to document the as-built condition; an engineering review of the anchor redesign; revised shop drawings; fabrication of modified hardware; and potentially a remobilization if installation was paused. The schedule delay alone can affect not just the curtain wall contractor but the interior trades waiting to work behind the facade.
RFIs that require design changes — rather than just clarifications — also require architect's supplemental instructions or change orders, which add contract administration time and often result in claims for additional compensation.
The cumulative cost of a high-RFI curtain wall project is not a line item — it is distributed across time extensions, labor inefficiencies, remobilization costs, and contract disputes that affect everyone on the project.
How to Reduce RFIs at the Source
The most effective RFI reduction strategy is earlier, more complete documentation — not faster RFI processing. Specific practices that reduce curtain wall RFI volume include:
- Develop anchor layouts in coordination with structural slab geometry early. Do not treat anchor design as a shop drawing exercise. The anchor zone must be defined and coordinated during design development, before structural drawings are issued for construction.
- Complete facade-MEP coordination before issuing construction documents. Perimeter heating, ceiling heights, and mechanical penetrations must be resolved in the model, not in the field.
- Establish explicit tolerance requirements and confirm anchor adjustability range. Document the structural tolerance assumptions, the curtain wall fabrication tolerances, and the required anchor adjustment range — and verify that the anchor design satisfies all three.
- Use parametric models for curtain wall documentation. When panel geometry, grid spacing, and anchor layouts are driven by parameters rather than manually drawn, design changes propagate automatically. This reduces the manual update burden and the risk of inconsistency across documents.
- Resolve corner conditions and non-standard panel types early. Corner panels and transition conditions are disproportionate sources of RFIs. Design these conditions explicitly rather than leaving them for the facade contractor to resolve in shop drawings.
For a broader view of how LOD affects documentation completeness and RFI risk, see LOD in BIM: 100, 200, 300, 400 and what LOD do architects actually need.
Kora Studio and RFI Reduction
Kora Studio is a Revit-native plugin for unitized curtain wall design. Its architecture directly addresses several of the root causes of curtain wall RFIs.
The Grid Editor uses formula-driven dimension fields — when a panel dimension changes, the grid updates consistently. This eliminates one of the most common sources of documentation inconsistency: manually adjusted grids that drift from the panel schedule. The Panel Editor enforces the system logic of actual unitized panel fabrication: panels are either opaque or contain a window — there are no free-form glass panels that cannot be manufactured. This constraint prevents a class of design decisions that generate shop drawing conflicts later.
Because Kora operates within Revit and feeds directly into Revit schedules, the panel schedule and the model stay synchronized without manual reconciliation. Changes to panel types, grid spacing, or corner conditions update the schedule automatically.
Kora also includes corner panel support — one of the most RFI-prone conditions on unitized curtain wall projects — using the same system logic as Dextall's prefab facade systems.
According to data published on the Kora website, projects using Kora Studio report 84% fewer RFIs and $42K in average savings per project. Those figures reflect the compounding effect of earlier, more consistent documentation: fewer coordination gaps, fewer field conflicts, fewer change orders.
If your team is managing a unitized curtain wall project and RFI reduction is a priority, book a demo to see how Kora fits into your existing Revit workflow. For a broader view of how Kora addresses design-to-fabrication gaps, see Revit to build-ready: closing the design-to-fabrication gap.
FAQ
Why do curtain wall projects generate more RFIs than other building systems? Curtain wall involves tight tolerances, multi-trade interfaces (structure, MEP, interiors), long fabrication lead times, and extensive documentation packages. Any gap or inconsistency in documentation surfaces quickly once installation begins, because the field crews have no flexibility to improvise — the system is factory-fabricated to specific dimensions. This makes documentation quality especially critical and RFI volume especially sensitive to early coordination failures.
What is the most common cause of RFIs on curtain wall projects? Incomplete or uncoordinated documentation is the most common root cause. This includes anchor layouts not reconciled with structural slab geometry, panel schedules inconsistent with the model, and corner or transition conditions left unresolved. These gaps are not visible in individual documents — they only surface when documents from multiple trades are read together, which typically happens in the field.
How much do RFIs cost on a curtain wall project? The administrative cost of writing and responding to an RFI is relatively small. The real cost comes from the resolution: engineering review, revised shop drawings, modified hardware, remobilization, schedule delay, and the cascade effects on interior trades waiting to work behind the facade. Projects using Kora Studio report $42K in average savings per project, which reflects the compounding cost of RFI reduction across the full project lifecycle.
Can RFIs be eliminated entirely on curtain wall projects? Not entirely — some RFIs are genuine field discoveries that no amount of planning could prevent. But the vast majority of curtain wall RFIs are preventable through earlier coordination, more complete documentation, and parametric models that stay consistent when design changes. The goal is not zero RFIs but a dramatically lower baseline: fewer conflicts, faster resolutions, and no surprises during fabrication.
How does Kora Studio reduce RFIs specifically? Kora's formula-driven Grid Editor keeps panel dimensions and grid spacing consistent — changes propagate automatically rather than requiring manual updates across multiple drawings. The Panel Editor enforces fabrication-realistic constraints that prevent design decisions which would generate shop drawing conflicts. The model feeds directly into Revit schedules, eliminating manual reconciliation between the model and the schedule. Together, these features address the documentation inconsistency that is the primary source of curtain wall RFIs.
