What Does "By Others" Mean On An Engineering Drawing?

"By others" on an engineering drawing means the item shown is outside that consultant's design scope, and someone else has to design it. Sometimes that is a fair line between disciplines. Sometimes it is a hole in the job, and the builder finds out when the concrete is booked.

Those two words carry real money, because whoever prices the drawings has to know who is designing that item, who is paying for it and when it will turn up.

When it is a fair note

Plenty of work belongs to someone else, and a note saying so is honest documentation. We don't design hydraulic services, fire engineering, electrical reticulation or air conditioning, and our drawings will say that those penetrations and loads come from the specialists who do.

Proprietary and contractor-designed items are the other fair case. Precast connection hardware, or [steel shop drawings](/blog/steel-connection-design-and-shop-drawings) from a fabricator working to the engineer's design forces, are normal ways to run a job. The test is simple: the note should name who does it, what they need to work from and who checks their work.

When it leaves a hole

The note causes trouble when the item sits inside the discipline that wrote it. These are the ones to look for on a structural or civil set:

Reinforcement detail by others. A slab or a wall shown with no laps, dowels or cover, or a detail left to the steel fixer's reading of the code.

Connection detail by builder. The member is sized, but the joint that makes it work is not.

Sequencing by builder. Temporary stability, propping and the order of the pours left open, even though the design relied on a particular order. Backpropping is a common one.

Crane base by others. The crane is shown on the plan, but nobody has checked the slab or the ground under it.

Shoring by others. The basement wall is drawn, but the piles, capping beam and anchors that hold the excavation open while it gets built are left to a second consultant.

Every one of those is a design someone still has to do, usually after the tender has closed and with less time than the first engineer had.

What it costs on site

A hole in the documents shows up in three ways on a job.

First comes the price. A builder pricing the drawings either carries an allowance for the missing design or leaves it out, and two tenders on the same set can differ by exactly that gap. Next comes the delay, because a second consultant has to be engaged, briefed and paid while the programme keeps running.

Then there is the coordination. A shoring designer working separately from the basement designer has to guess at the loads and levels, and each guess turns into an [RFI](/blog/construction-rfis-and-how-engineers-answer-them). When a change later lands on site, the question of who is responsible gets harder to answer with two engineers holding one wall.

The legal edge on Class 2 work

On a Class 2 apartment building in NSW, the gap has a legal side as well. The Design and Building Practitioners Act 2020 requires regulated designs to be prepared and declared by registered design practitioners, and the builder needs those declared designs in hand before the work they cover starts. The registration side is set out in [design practitioner registration in NSW](/blog/design-practitioner-registration-nsw).

An item left to the builder doesn't stop being a design. It still needs a practitioner, a set of drawings and a declaration, so the note only moves the question down the programme.

How to find them before tender

Read the general notes first, because scope exclusions tend to live there rather than on the plans. Then run a word search across the PDF set for "by others", "by builder", "by contractor" and "refer to". It takes ten minutes.

Put each hit in a table with three columns: the item, who is designing it, and when their drawings arrive. Any row you can't fill in is a question for the engineer before the tender closes, because it is a much cheaper question then than it will be on site.

Ask the same question about the things the drawings don't mention at all. A set that is silent on the excavation sequence or the propping has the same gap, without the courtesy of a note.

How we approach it

We treat a by-others gap inside our own scope as a defect, not a way to trim the job. When we design a shoring system, that means the piles, the capping beam, the anchors and the shotcrete, along with a walk through the bulk excavation procedure.

Before a set is issued for construction, our drafting manager and a senior engineer review it sheet by sheet for those gaps, and they get closed before the builder ever sees them. The reasoning sits in [why engineering drawings must be buildable](/blog/why-engineering-drawings-must-be-buildable).

The only phone calls left on a job should be about the things nobody could have known.

ACSES provides structural, civil and geotechnical engineering under one roof across Sydney. Talk to us about a project.

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