The $860,000 cost of reading your own drawings

The average project spends $860,000 clarifying its own documents

$859,680 per project. That is what the average project in the largest study on the subject spent on requests for information, RFIs: formal written questions from the contractor to the designer or owner, raised when the drawings and specifications are ambiguous, contradictory or silent. The RFI is construction's standing admission that the documents did not speak for themselves. The Navigant Construction Forum analysed 1,362 projects worldwide, started between 2001 and 2012 and worth $5 million to $5 billion each, drawing on the Aconex document platform: 1.1 million RFIs in total, an average of 796 per project.

Each RFI takes an estimated 8 hours of designer and reviewer time to process, at an average cost of $1,080 in 2013 dollars. Multiply by 796 and the average project spends 6,368 hours and $859,680 on clarification alone. Not on design changes, not on extra work: on explaining documents that were delivered as finished. The study's authors put their conclusion mildly:

The RFI ledger

The dataset is thirteen years old, which makes it conservative. Industry estimates today run higher: a sponsored piece in the trade outlet Construction Dive put the 2024 range at $2,000 to $3,000 per RFI, before indirect costs such as delays and rework. The 2013 figures below are the documented anchor. One ratio is worth memorising: 9.9 RFIs per million dollars of construction value. On a $100 million project, that is roughly a thousand questions.

Each handoff turns ambiguity into a question

Every RFI is a question the documents should have answered. The mechanism is the handoff. A designer writes a specification with one intent. The main contractor reads it through the lens of bidding and sequencing. Each subcontractor reads only their own slice. A tolerance that differs between drawing and text, a reference that changed after the template was written: each becomes a query, a wait and a guess. The defect also grows as it travels. One hour of ambiguity at the designer's desk becomes hours of tender queries at the main contractor, hours again at every affected subcontractor, and schedule slip if the question lands during execution. Vrijhoef and Koskela's study of the construction supply chain drew the conclusion the field still cites: most problems are caused in a different stage from the one where they are detected.

The waiting is its own cost. A median answer time of 9.7 days means each question sits in someone's schedule for a week and a half; on the critical path, that is delay bought at site rates. And 21.9 percent of RFIs never receive an answer at all. Those questions do not disappear. The crew decides for itself, and the decision is either right, or rework. In Swedish contracts the same defect surfaces further downstream, as ÄTA change orders: where the tender documents were incomplete, the contractor invoices the difference.

The rate has not moved

Navigant measured 9.9 RFIs per million dollars in 2013. A decade of BIM mandates, common data environments and information-management standards later, nothing in published industry data shows that ratio falling. Whatever BIM has fixed, it has not fixed the text: linear infrastructure in particular still runs on 2D drawing sets and text-heavy specifications, where the contradictions hide between document types. The defect that generates the questions is structural: documents produced under time pressure, by fragmented teams, checked by hand, at human speed.

That last part is what has changed. An RFI is document work from end to end: find the clause, read it against the drawing, check the requirement, write the answer. That searching, cross-checking and drafting can now be done in minutes, and a design package can be checked against itself before it goes out, so the question is answered before it needs asking. The $860,000 is not a toll that has to be paid. It is a measure of how much of a project's intelligence goes into reading its own drawings.