Construction RFIs And How An Engineer Should Answer Them

A request for information, or RFI, is the builder's formal question to the design team when the drawings do not settle something on site. A good engineering answer resolves the question underneath the one that was asked, gives the reasoning, and issues updated drawings whenever the answer changes them.

RFIs are normal on every job. What decides whether they cost a day or a week is how they are asked and how they are answered.

Why RFIs happen

Most RFIs come from a handful of places. Services clash with structure. A detail is missing for a condition the drawings did not anticipate. The existing building or the ground turns out to be different from what was assumed. Or the builder wants to do something a different way, with a different bar size, a different product or a different sequence.

Every one of those stops a trade until it is answered.

What a clear RFI includes

One question. Two questions in one RFI tend to get one answer.

The reference. Drawing number and revision, gridline and level, so there is no doubt which element is meant.

A picture. A site photo or a marked-up sketch removes more confusion than a paragraph.

The proposal. If the builder has a solution in mind, putting it in the RFI lets the engineer check it rather than design from scratch.

The deadline. The date the answer is needed, tied to the pour or the trade that is waiting on it.

What a proper answer covers

The engineer's job is to answer the question that sits under the literal one.

Take a builder asking to swap a bar size because the specified bar is hard to get. The literal answer is yes or no. The real answer covers whether the new bar gives the same steel area at the same spacing, the longer lap length that comes with a larger bar, whether the cover still works at a congested junction, and whether any of that changes the pour. The congestion side of that question is covered in [reinforcement detailing and congestion](/blog/reinforcement-detailing-and-congestion).

Then comes the updated detail. A one-line "approved" with no reasoning and no drawing leaves the builder exposed and the certifier with nothing to check against.

When the answer changes the design

If the answer changes the drawings, a revised drawing is issued, and the reason for the revision refers to the RFI number. That matters at the end of the job, because certification follows the drawings actually used on site, as described in [structural certification and inspection certificates in NSW](/blog/structural-certification-and-inspection-certificates-nsw).

Changes made on site without an RFI are a different and riskier story, set out in [who is responsible when a design changes on site](/blog/who-is-responsible-when-a-design-changes-on-site). And an RFI that adds work or changes the design intent is really a variation. It is priced and agreed before it is built, not argued about afterwards.

Response times

Not every RFI is equally urgent, and treating them as if they were slows down the ones that are.

A question on pour day, with a concrete truck booked and a crew standing on the deck, is answered the same day. Routine clarifications are turned around within a business day or two. A question that needs re-analysis takes longer, and the builder is told when to expect the answer rather than left waiting.

The register

Every RFI is logged on a register: number, date, who asked, the question, the date answered, the resolution and any drawing it changed.

The register is the audit trail for certification and handover. It is also a mirror. When the same detail keeps generating RFIs, the problem is the drawing, and the drawing gets fixed.

Drawings that prevent RFIs

The best RFI is the one that never needs asking. Drawings coordinated with the architecture and services before they are issued for construction, and detailed so a builder can build without interpretation, cut the number down before the job starts. The reasoning is in [why engineering drawings must be buildable](/blog/why-engineering-drawings-must-be-buildable).

How we approach it

We answer RFIs with the reasoning, the calculation or reference behind it, and the updated drawing where one is needed, and we prioritise by what the site is waiting on. Every RFI marks a spot where a drawing stopped short, and answering it properly means the next site never has to ask.

ACSES provides structural engineering and construction phase support across Sydney. Talk to us about a project.

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