Key takeaways
- A single controlled source of current drawings must be nominated in writing, because a tablet is only as good as the revision it is displaying.
- Superseded digital drawings are more dangerous than superseded paper because they are identical on screen and easy to forward, so the issue register must record who holds which revision.
- Markups on site are records and should be made in a way that can be exported, attributed and dated, not drawn on a personal copy that never returns to the office.
- The revision control process needs to cover subcontractors and consultants, because the principal contractor carries the consequences of a subbie building from an old sheet.
- Handover documentation must show the revision that was actually built, which means as-built markups have to be captured progressively rather than reconstructed at the end.
Most builders who move to digital drawings on site do it for the obvious reasons: no more folded A1s in the ute, no more hunting for the latest sheet, and markups that can be sent back to the office without a courier. The tablet is not the hard part. The hard part is revision control — making sure that the sheet on the screen is the sheet that should be built, and that every person on site is looking at the same one.
Paper had a crude but effective control: the superseded sheet got a stamp, or it got physically removed from the site folder. Digital drawings do not announce themselves. A superseded PDF looks exactly like a current one, opens the same way, and forwards in a message with one tap. That is the risk this article deals with.
The workflow below is about revision control and markup discipline. It is not about which app to buy. If you are still choosing software, the principles here will tell you what to insist on. If you already have it, they will tell you where your process is likely to fail.
Why digital drawings change the revision risk, not remove it
On paper, the physical world did some of the revision control for you. There were only so many copies, they were heavy, and the person who held the site set could see when a new roll arrived. Digital drawings remove those accidental controls. Copies multiply instantly, old versions sit in downloads folders and message threads, and nothing about a file tells you whether it is current.
The consequence is that a revision error can travel further and faster than it used to. A subcontractor who was sent a superseded sheet can forward it to their own crew, and by the time anyone notices, work is in. The cost of that is not just rework. It is the programme delay while the work is demolished and rebuilt, the argument about who pays for it, and the possibility that the error is buried in a slab or a wall before it is found.
Safe Work Australia’s guidance on digital technologies and AI is a useful reminder that digital tools on site are still tools within a safety management system. The same logic applies to drawings: the technology does not replace the control, it changes the form the control has to take. A tablet is not a revision control system. It is a screen that displays whatever revision control system you have put behind it.
Nominate one controlled source of current drawings
The first decision is not technical. It is a decision about authority: which copy of the drawings is the controlled copy, and who is allowed to say a revision is current. On most jobs the answer is the principal contractor, because the principal contractor carries the consequences. That authority should be written into the contract documents and the site induction, not assumed.
In practice, a controlled source means one location — a document management platform, a project folder, or a cloud drive with proper permissions — where the current revision of each drawing lives. Anything else is a copy. Copies are allowed, but they are downstream of the controlled source and they expire the moment a new revision is issued.
The reason this matters is that revisions do not arrive from one direction. Architectural, structural, civil, hydraulic and electrical drawings can all be revised at different times, and the revision letters or numbers will not line up across disciplines. If there is no single controlled source, the site ends up with a mix of current and superseded sheets and no way to tell which is which without checking each one.
For builders working through their CPD obligations, this is also a supervision issue. The guide to NSW builder supervision duties sets out why the person supervising the work has to be able to demonstrate that the work was carried out to the current documentation. Revision control is how you demonstrate it.
Build a revision register that survives contact with site
A revision register is a simple table: drawing number, title, current revision, date received, date issued to site, and who holds it. It sounds bureaucratic until the first dispute, at which point it is the only thing that shows what was issued and when. The register does not need to be sophisticated. It needs to be current and it needs to be accessible from site.
The register should record two different things. First, what the current revision is. Second, who has been given it. Those are not the same question, and the gap between them is where most revision failures live. A drawing can be current in the register while a subcontractor is still working from the previous version because no one sent them the update.
When a revision arrives, the register entry changes, the superseded revision is removed from the controlled locations, and the new revision is transmitted to every holder. The transmission should state what it replaces and whether any action is required before the work proceeds. Where a revision affects work already under way, that is a variation conversation, not just a document update, and it should be handled as one.
Issuing a drawing revision so it cannot be built from twice
- 1Receive and checkCompare the incoming revision against the previous one and confirm what actually changed before it goes anywhere.
- 2Register itRecord the revision, the date it was received and who is responsible for distributing it.
- 3Replace, do not addRemove the superseded revision from every controlled location so only the current sheet can be opened.
- 4Distribute with a transmittalSend the revision to each holder with a clear statement of what it replaces and what action is required.
- 5Confirm receiptGet acknowledgement from each holder, including subcontractors, so you know the old sheet is out of circulation.
Markups on site: make them records, not scribbles
On paper, a markup was a pencil line on a drawing that then went back to the office and was redrawn. On a tablet, a markup can be a permanent, attributed, dated annotation that stays with the drawing. That is a significant improvement, but only if the markup is made in the right place. A markup drawn on a personal copy that never returns to the controlled source is worth nothing.
The working rule is that markups are made on the controlled copy, or on a copy that is synchronised back to it. The tool should record who made the markup and when. This matters for two reasons: it creates a record of site decisions, and it prevents the same question being resolved twice because no one can remember the answer.
Markups fall into a few categories, and they should not be treated the same way:
- As-built markups record what was actually built where it differs from the drawings. These are the ones that matter at handover.
- Coordination markups record clashes or set-out issues that need a design response. These should be raised formally, not left as a note on a sheet.
- Query markups are questions. They need an answer and a closed loop, or they become a variation argument later.
- Safety or access markups record something about how the work is done rather than what is built. These belong with the safety documentation as well as the drawing.
The most common mistake is mixing them. If a single sheet carries as-built records, unanswered queries and coordination notes with no status, the next person to open it cannot tell what has been resolved. A simple convention — a colour, a layer, or a tag — is enough, provided everyone uses it.
Tablets and devices: what has to be true before they go out
A tablet on site is only as useful as its setup. The drawings need to be legible at the zoom level a supervisor will actually use, which means the original files matter more than the screen size. A drawing that is readable on a desktop but blurry on a tablet will not be used, and a drawing that is not used is not a control.
Devices also need to handle the conditions on site. Glare, dust, gloves and battery life are real constraints. If the tablet cannot be used comfortably with gloves on, markups will not happen in the moment, and markups that happen later are less reliable. Offline access matters too, because basements and new builds often have poor coverage, and a drawing that will not open is worse than a paper copy that will.
The most important setup point is the update path. Either the device syncs to the controlled source automatically, or there is a documented process for updating it and a nominated person responsible for checking. A device that holds a static copy of the drawings is a paper drawing with extra steps, and it will go out of date.
Tablet setup checks before the drawings go out
- The current revision set is loaded and the previous revision has been removed.
- Every sheet is legible at the zoom level a supervisor will actually use on site.
- Markup tools are set so annotations carry an author and a date.
- The device syncs to the controlled source, or has a documented process for updating it.
- Offline access works in the areas of the site where coverage is poor.
- Subcontractors have been given access to the same current set, not a forwarded copy.
- A nominated person is responsible for checking that the set on each device is current.
Subcontractors and consultants: the revision control boundary
The principal contractor’s revision control usually stops at the site gate, but the risk does not. Subcontractors work from the drawings they are given, and if they are given a superseded sheet, they will build from it. The contract should make it clear that the subcontractor is responsible for working from the current revision and for checking before they start, but the practical control is that they receive the revision directly and confirm it.
Forwarding a drawing by message is the weak point. A subcontractor who receives a drawing in a message thread has no way of knowing whether it is the latest, and no way of being told when it is superseded. Where the project has a document platform, give subcontractors access to the controlled source rather than sending files. Where it does not, the transmittal and acknowledgement process has to be explicit, and it has to be repeated for every revision.
Consultants sit on the other side of the boundary. Their revisions come into the controlled source and then out to site. The delay between those two events is a risk in itself, because work can proceed on the old revision while the new one sits in an inbox. Someone has to own the step between receiving a revision and getting it to the people who are building.
Handover: proving the revision that was built
At practical completion, the question is not what the drawings said. It is what was built. As-built markups are the record of that, and they have to be captured as the work proceeds. If they are reconstructed at the end from memory, they will be incomplete, and the person reconstructing them will not remember the small deviations that matter later.
The handover set should show the revision that was current when the work was done, plus the as-built markups that record the differences. Where a revision was issued after the work was built, the record needs to show which revision the work was actually built to. That is the document a certifier or a future owner will rely on, and it is the document that protects the builder if a question arises years later.
The commercial reality is that handover disputes are usually about records, not workmanship. A builder who can produce a clean revision history and legible as-built markups is in a much stronger position than one who cannot, even where the work itself is identical.
Worked example: a builder in western Sydney
A builder in western Sydney is running a two-storey residential project with a hydraulic design that is revised twice during construction. The first revision changes a pipe route through a service void. The second changes the location of a floor waste.
The builder has a controlled source for drawings and a revision register. The first revision is received, registered, transmitted to the plumber and acknowledged. The superseded sheet is removed from the site folder and from the tablet set. The plumber builds the revised route.
The second revision arrives while the plumber is on another job. The office registers it but does not transmit it immediately, because the person who normally does it is away. The plumber returns to site and sets the floor waste from the sheet they already have, which is now superseded. The error is found at fit-out, after the screed is down.
The cost is not just the rework. It is the demolition of the finished floor, the delay to the tiler, and the argument about who pays. The builder’s position is weaker than it should be, because the register shows the revision was received but there is no record of it being transmitted. The fix in this case is procedural, not technical: a nominated backup for transmission, and a rule that no revision sits unissued for more than a day. The same rule, applied consistently, is what makes the digital drawing set trustworthy.
Where this fits in your CPD and your systems
Revision control is one of those areas where the requirement is not new, but the method has changed. The obligation to build to current documentation has not moved. What has moved is the number of ways a superseded document can reach the workforce, and the speed at which it can be built.
If you are working through your annual CPD, the guide to how NSW builder CPD works explains the structure and what counts. Documentation and site management topics are a natural fit, because they connect directly to the supervision duties you already carry. The PointCPD course catalogue lists the courses available, and the PointCPD home page is the starting point if you are new to the platform.
The practical takeaway is that digital drawings do not need a better app to be safe. They need a system: one controlled source, a register that records who holds what, markups that are made in the right place, and a transmission step that cannot be skipped. Get those right and the tablet is an improvement. Get them wrong and it is a faster way to build the wrong thing.
Questions builders ask
How do I stop subcontractors working from superseded digital drawings?
Give them access to the controlled source rather than sending files, and transmit each revision directly to them with a clear statement of what it replaces. Require acknowledgement, and check that the superseded revision has been removed from their set. The contract should also make it clear that they are responsible for working from the current revision.
Should markups be made on the tablet or on a printed copy?
Either can work, provided the markup ends up in the controlled record. A markup on a personal copy that never returns to the office has no value. If you mark up on paper, photograph or scan it back into the controlled source the same day. If you mark up on a tablet, make sure the tool records the author and date.
What should a revision register actually contain?
At minimum: drawing number, title, current revision, date received, date issued to site, and who holds it. The register should answer two separate questions, which are what the current revision is and who has been given it. The gap between those two answers is where most revision failures occur.
Do I need a document management platform, or can I use a cloud folder?
A cloud folder with proper permissions can work on a small job if there is a nominated person controlling it and a consistent naming convention. The risk with a folder is that copies multiply and permissions drift. A document platform makes the control explicit, which is why it becomes more valuable as the number of consultants and subcontractors grows.
How do I handle as-built markups at handover?
Capture them as the work proceeds, not at the end. By handover, the record should show the revision that was current when the work was done and the markups that record any differences. Where a revision was issued after the work was built, the record needs to identify which revision the work was actually built to.
What is the biggest revision control mistake on site?
The most costly mistake is receiving a revision and not getting it to the people who are building. The register shows the revision arrived, but no one transmitted it, so the work proceeds on the old sheet. A nominated backup for transmission and a rule that no revision sits unissued for long will prevent most of these failures.
Sources
- Digital technologies and AI · Safe Work Australia
- Flood risk management manual · NSW Government
Published 28 June 2026. General information for builders, not legal, financial or engineering advice for a specific job. Check current requirements with the relevant regulator or standard before relying on them.
