Tracking Change Orders and Client Approvals on Construction Jobs

Why a missing signature costs money

Change orders are normal on building work, but they are where many jobs lose margin. A trade column in CNR Magazine describes change orders as averaging around 10 percent of total contract value, with some projects reaching 25 percent. A 2026 guide from the construction software vendor Rhumbix puts the figure for major projects at 10 to 15 percent, and says some reach 25 percent or more. The two sources agree on the order of magnitude. Neither is a government statistic, so treat these as planning ranges, not promises about your job.

To make that concrete: on a contract worth 2,000,000 in any currency, a 10 percent change load is 200,000 of work that was never in the original price. If half of that work starts on site before the client has signed, the business is carrying cost it may not be able to recover. The loss does not come from the change itself. It comes from the gap between instruction and signature.

The risk is well known in contract practice. The guidance from Sirion, a contract management software company, is that work on a change should not begin before written approval is secured. The same guidance points to the signed change order as the document that lets the contractor carry out the modified work. Ressio, a construction accounting and software firm, gives a similar test in its builder guide: a signature or a documented in-system approval is the only acceptable form of approval. Verbal agreement from a site superintendent does not count.

Older data points to the same weakness. A 2001 analysis by Purdue University of Indiana Department of Transportation contracts, covering 1996 to 2001, found an overall cost overrun rate of 4.5 percent and recommended a formal change order management process with set procedures for recording each change. That study concerns public highway work, so its numbers do not transfer directly to a building firm. The recommendation still holds: record changes as they happen, not at the end.

Three costs tend to show up when approvals drift:

• Unbilled work. Labour and materials go into the job, but the variation never reaches the client's approval queue, so it is not invoiced.
• Disputes. The client remembers a conversation differently from the site team, and nothing in writing settles it.
• Margin erosion. Small changes that were never priced accumulate into a gap that surfaces at final account.

The manual way and the automated way

Most firms start with a spreadsheet, a shared folder and a phone call. That works on a small job with one site and one client contact. It starts to fail when several subcontractors, a site engineer on the road and a client with three reviewers are all sending instructions by WhatsApp, email and text.

The table shows where automation helps. It does not replace the judgement on price, scope and whether the change should happen at all. That stays with the project manager.

Step-by-step: how to set this up

You do not need a large software project to start. The steps below work with a shared spreadsheet and a messaging channel, and they scale up to a construction management platform when the job count justifies it.

1. Create one change register per contract. Give each change a number, a date, a source (site, client, designer), a short description and a status. Keep the original contract value as a fixed line at the top, and build the approved change total below it. Do not let anyone edit the original value.
2. Set a single intake route. Choose one place where site staff send change instructions. For many firms that is a WhatsApp Business number or group that the office monitors, plus email for clients who prefer it. Tell crews that an instruction given only verbally is not yet a change until it is logged.
3. Automate the log entry. A simple workflow in Microsoft Power Automate, Zapier or a similar tool can take a new message or form entry and create a row in the register with the time stamp, sender and attachment link. Where site staff send voice notes, a speech-to-text step and a large language model can draft the description for a person to check. The draft is never the record; the person's confirmed text is.
4. Attach the cost request in a fixed format. Require the same fields each time: drawing or specification reference, photos, labour hours, materials, subcontractor quote, markup under the contract, and schedule impact in days. Where a supplier delivery note or quote arrives as a photo, optical character recognition (OCR) can read the figures into the register, such as the open source engine Tesseract. Check every extracted number against the source image before it goes anywhere.
5. Send the approval request in the client's agreed channel. Email with an e-signature link, such as DocuSign or Adobe Acrobat Sign, is the most common route for a formal signature. For clients who work mainly on WhatsApp, the Cloud API of the WhatsApp Business Platform can send a template message with the change number, the amount and a link to the document. Meta's documentation says the On-Premises API was sunset on 23 October 2025, so new builds should use the Cloud API.
6. Set a chasing schedule. A sensible pattern is a reminder at 2 working days, a second at 5, and an escalation to the project manager at 7. Adjust the days to the client's review habits. The schedule should be written into the register so that everyone can see the age of each open item.
7. Move signed items into the value register only. When the signed document is filed, the status changes to approved and the register total updates. Unsigned items stay in a separate pending column. Nothing in the pending column should be billed or treated as agreed.
8. Authorise work in writing. Before a crew starts a change, the register should show an approved status and the work order should reference the change number. If the client wants work to start before the signature, the project manager records that decision and the reason in the register, so the exposure is visible.
9. Review the register weekly. Once a week, the project manager and the finance lead go through the pending items by age, the approved total against the original contract value, and any change the site has logged but not yet priced.

If you use a construction platform, the same logic is built in. Procore, for example, describes its change order software on its own product page as able to capture changes from mobile devices and to sync pending and approved changes with its budget tool. Its support documentation also says that approved or billable change orders are added to the next invoice automatically, while the user can add or remove items manually. Check those settings against your contract before you rely on them. A platform is only as accurate as the approval rules you configure.

The public sector shows the same pattern at scale. The Wisconsin Department of Transportation's contract system sends an automatic notification to each approver when it is their turn, and locks a change order once final approval is given. You can copy the logic without the cost of a government system: one step at a time, one owner per step, and a locked record once approved.

What breaks, and how to prevent it

Most failures are not technical. They come from unclear rules about who can instruct a change and who can approve it. Here are the common breakdowns and how to prevent each one.

Verbal instructions become changes. A site engineer tells a subcontractor to add a fixture, and nobody logs it. Write the rule into the site instruction: no instruction is a change until it has a number. Check the register against the daily site report each week.

The client's approver is not the person who signs. The register shows a request approved by the site contact, but the contract requires a director's signature. Record the authorised signatory for each client at project start. The contract's change procedure usually names who can approve, and that clause should be read before the first change is sent.

Messages get lost in a group chat. A WhatsApp group with twelve people is not a register. Use one business number or a dedicated group with the office as the owner, and copy every instruction into the register. Messages that disappear from a phone cannot be audited.

Automatic reminders annoy the client. A client who receives four reminders in one day may stop answering. Keep the reminders to the agreed schedule and send them from a named person, not a system address.

The OCR or language model gets a number wrong. A quote figure of 14,500 is read as 14,000. Require a person to check any extracted amount against the image, and keep the original file attached to the register line.

Price is wrong. Automation will faithfully record a poor estimate. Set a rule that the project manager signs off the price before the request goes out, and that the finance lead checks the markup against the contract's allowed rate.

The register and the invoice drift apart. Billing happens from a copy that was not updated. Make the register the single source for change value, and have the invoice check run against the register before each client billing cycle.

Automation can record and remind. It cannot decide whether a change is fair, whether the site is describing the problem accurately, or whether the client has understood the cost. A person still makes those calls, and the register is only useful if they are made on time.

When not to automate

Automation is not worth building for every job. If you run a single small fit-out a year, with one client who signs everything within a day, a shared spreadsheet with a weekly review is enough. Setting up intake routes, templates and approval rules takes effort that a single job will not repay.

Hold off on automation if your contracts are not yet clear on change procedure. A workflow cannot correct a contract that gives the client no timeline for responding, or that allows the contractor to proceed without written approval. Read the change clause first and agree the process with the client before building anything. Where the contract is unclear, a construction lawyer should review it; this guide is not a substitute for that review.

Do not automate the pricing decision, and do not let a language model write the cost basis. Its job is to organise what the people on site and in the office have already recorded. If the site data is poor, the register will reflect that poorly, and no tool will fix it.

Finally, avoid automation where the client relationship depends on personal contact. Some clients want a phone call before they sign anything. Keep that step. The automated reminder should follow the call, not replace it.

What it takes in time

For a firm with one or two active jobs, expect a few days to set up the register, agree the intake route with the site team and write the approval schedule. Build the first workflow on one job, run it for two or three weeks, and fix the gaps before rolling it out. The main effort is not technical. It is getting the site, the office and the client to agree on what counts as an instruction and what counts as an approval.

On a larger group with several projects and a dedicated project controls team, expect a longer rollout. Plan for a few weeks of configuration in a platform, a period of parallel running where the spreadsheet and the system are both maintained, and a training session for each role. Time spent on the approval rules at the start saves rework later.

Whatever the size of the firm, the weekly review is the habit that matters most. It takes about an hour for a single project and should not be skipped. It is the point where an unsigned change is found before it becomes an unpaid one.