Keeping site instructions as evidence for variations

How a contractor files site instructions, drawing revisions and certificates in Achekam so they stand up when a variation is disputed months later.

By Achekam · 11 October 2026 · 5 min read · For Construction businesses in South Africa, Nigeria, Kenya

On a site walk the client's engineer stops at a window opening. "Move that across, and put in a deeper lintel." The site agent nods, the work is done that week, and everyone is happy. Six months later, at the final account, the quantity surveyor asks where the instruction is. Nobody can find it. The variation is cut.

Contractors rarely lose variations because the work was not done. They lose them because they cannot prove someone with authority asked for it, or which drawing was current at the time. This article sets out a way to keep site instructions, drawings and certificates in Achekam's Documents so that, when a variation is questioned, the evidence is there, dated and unchanged.

Why verbal instructions cost contractors money

Most building contracts require instructions to be given, or confirmed, in writing, often within a short period. An instruction that was only spoken leaves three gaps:

• who gave it, and whether they had authority to;
• what exactly was asked for;
• when, and against which revision of the drawings.

Each gap is a reason for the client's side to refuse or reduce the claim. The habit that closes them is a written confirmation of every verbal instruction, sent quickly, plus a filing system that keeps every version of every document.

A folder per job, tagged by instruction, drawing and certificate

Document Centre is a folder-based store where a business uploads files or whole folders, previews, downloads, renames, moves, tags, archives and searches them. Uploads go in batches of up to 25 files, at up to 100 MB per file by default, which is enough for most drawing sets.

A folder structure that works for most jobs:

Tags matter more than folders. When the QS asks about the lintel, a search on the instruction number or the area should bring up the instruction, the drawing it changed and the photos of the work.

Drawing revisions kept as versions rather than overwritten

When a new revision of a drawing arrives, upload it as a new version of the same document rather than as a separate file, and never delete the old one. In Document Centre a new version keeps the earlier ones.

That is the point of the exercise. In a dispute, the question is often not what the drawing says now but what it said on the day the work was done. With every revision kept, you can show exactly which version the site was building to, and when the change came in.

Getting an instruction confirmed by signature

The strongest evidence is an instruction signed by the person who gave it. Any document can be sent for electronic signature, with signature and initials fields placed on it, signers in order or all at once, an expiry and reminders. The signed PDF and a completion certificate are then filed back into Documents.

A practical routine for verbal instructions:

1. The site agent writes a short confirmation the same day: what was asked, by whom, where, and which drawing it affects.
2. The office sends it for signature to the person who gave the instruction. An envelope with a signer from outside the business must be linked to a client or a CRM lead before it is sent, so the client's agents should be set up on the client's record.
3. When it is signed, Achekam produces the signed PDF with a completion certificate listing each signer's e-mail, times, IP address and browser and the document's fingerprint, and files it in the client's Signed documents folder.
4. If the agent will not sign, keep the confirmation and the e-mail that sent it; an unanswered written confirmation is still far better than nothing.

Fingerprints that show a file has not changed since it was filed

Every stored file in Achekam gets a SHA-256 fingerprint: a code worked out from the file's exact contents. If the file changes, even by one character, the fingerprint changes too. Executable files are refused by default, and every upload passes a malware check.

The fingerprint does not prove who wrote a document or that what it says is true. What it does show is that the copy you produce today is the same copy that was filed on the day, which is often the very thing the other side questions. In South Africa, the Acts Online text of section 16 of the ECT Act sets out when keeping a record electronically satisfies a legal duty to retain information, including the requirements of accessibility, integrity and origin; Nigerian and Kenyan contractors should ask their lawyer how electronic records are treated in their own courts.

Sharing evidence with the client's agent through an expiring link

When the QS asks for the evidence behind a variation, do not attach twenty files to an e-mail. A document can be shared by e-mailing a personal link with an expiry, an optional one-time code, and download allowed or not, and the share can be revoked. Share the instruction, the drawings and the photos, set a sensible expiry, and revoke the link once the variation is agreed.

Making it a habit

Give every site agent a simple rule: no instruction acted on without a written confirmation sent the same day. Set up the folders and tags for each new job before it starts, as part of the same paperwork that gets a building quote accepted in writing. Law firms run matter files on the same principle, as matter files in the Document Centre shows. When the evidence is in order and a certificate still comes in short, the payment certificate that is less than you claimed explains the next step.

General guidance only, not advice on your own circumstances. Tax and payroll rules change: check the current position with the authority or your adviser.