Site Instruction vs Variation: What Is the Difference and Why It Matters

Half of the subbies who lose money on variations lose it because they treated a site instruction as a variation, or treated a variation as a site instruction. They are different commercial events. Mixing them up costs.

The simple distinction

• A site instruction is a direction to perform work that is already in your scope, but in a particular way, sequence, or location.
• A variation is a change to your scope. The work is now different from what you priced.

A site instruction is a project management nudge. A variation is a contract change. They generate different documents, different evidence chains, and different commercial outcomes.

Site instruction examples

You receive a site instruction when the head contractor's superintendent or PM tells you:

• "Start at Level 5 instead of Level 1 because Level 1 is not ready."
• "Use the goods lift today, the passenger lift is closed for fitout."
• "Hold install on the south wall until the electrician finishes the rough-in."

In every case, the work is the same. The way you do it is being directed.

Site instructions do not normally trigger a cost claim. They sometimes trigger a delay or sequence impact, which is a different claim.

Variation examples

You receive a variation when the head contractor:

• "Add a fire-rated door to Level 2 Apartment 14." (work outside your original scope)
• "Replace the ceiling tile spec from Standard to Acoustic." (specification change)
• "Re-do the install in Apartment 12 — the carpenter damaged it after our handover." (rework caused by another party)

In every case, the work is different from what you contracted to do. The cost and time impact is real.

How to document each

Site instruction documentation

When you receive a site instruction, create a written record of it within 24 hours. The record contains:

• Date and time of the instruction
• Who gave it (name, role)
• What was instructed (verbatim if possible)
• Whether it was verbal or written
• Whether your trade has any impact (delay, sequence change, materials change)

If the instruction has cost or time impact, your written record turns into a delay notice, a variation submission, or a request for clarification — depending on the impact.

Variation documentation

When you receive a variation, you submit it for written approval before commencing the work. The submission contains:

• A clear description of the variation
• The trigger event (site instruction, RFI response, builder email, design change)
• The contract clause that puts the work outside your scope
• A cost breakdown — labour hours, materials, overhead
• A start date and duration
• Photos or supporting documents

A variation is not a variation until it is in writing. Verbal "yeah just do it" instructions are how subbies lose tens of thousands of dollars per job.

The traps

Trap 1: Doing variation work on a site instruction

The head contractor's PM tells you "just go ahead and add the door, we'll sort the paperwork later." This is the most expensive sentence in commercial construction.

You do the work. The PM forgets. The variation never gets approved. When you put it in your progress claim, the head contractor's commercial manager rejects it because there is no written approval.

Always insist on the variation in writing before you start. If the PM cannot give you that, send the variation submission yourself and document that you proceeded under a directed variation.

Trap 2: Treating a variation as a site instruction

If a written instruction arrives and the work is genuinely outside your scope, do not file it under "site instruction" and proceed. The work needs a variation submission with a cost breakdown. Otherwise, the head contractor argues the instruction was within your scope and you do not get paid.

Trap 3: Conflating impact

Some events generate both. The PM tells you "skip Level 1 and start on Level 5" (site instruction) but Level 5 is not ready and you are stood down (delay event). You log both — the instruction and the delay notice — separately.

What this looks like inside TradeControl

TradeControl has separate logging flows for site instructions, variations, and delays. Each event type has its own form, its own evidence chain, its own director-side review queue. When the head contractor disputes anything 6 months later, the right record is one tap away.

Book a 20-minute demo

---

TradeControl provides commercial support only. Not legal advice.