Variation Orders: When Normal and How to Control Them

A variation order is a change to the agreed scope of work in a construction contract, whether an addition, reduction, or replacement of a work item. In many projects, variation orders do happen. The more important question for you is not "will changes occur," but "how are those changes approved and calculated."

Why variation orders arise

Construction involves site conditions that are not always visible on paper. Common causes include:

• Existing conditions only revealed after demolition, such as old structures differing from initial assumptions. The article full home renovation: data before demolition explains why gathering data before demolition work begins matters.
• Change requests from you, such as swapping materials, adding space, or altering layout after the design has been approved.
• Technical adjustments from the design or construction team when inconsistencies between working drawings are discovered.
• Significant material price changes due to market conditions, though this is rarer and usually anticipated through a contingency fund.

The article RAB, BOQ, allowance, and contingency explains how a contingency fund serves as the first buffer before a variation order truly becomes necessary.

Normal variation orders versus ones worth questioning

A variation order is reasonable when it is based on documented field findings, a clearly recorded change request from you, or a technical adjustment genuinely needed to make the work buildable and safe. In these cases, the change is usually accompanied by a technical explanation that can be compared against the original bill of quantities (BOQ, a detailed cost breakdown by work item).

A variation order worth questioning is one that repeatedly appears for items that should have been clear from the start, lacks technical explanation, or is submitted after the work has already been completed. This does not always indicate bad faith, but it signals that the scope of work or working drawings need a more careful review.

Mechanisms that control variation orders

Controlling variation orders begins well before construction starts. Practices that help include:

• RAB (cost estimate) and BOQ prepared before the contract. The more detailed the breakdown of work items, the less room there is for differing interpretations on site.
• A design freeze before construction begins. This is the point at which the design is agreed to no longer change, so any adjustment afterward is clearly recorded as a variation order rather than a free design revision.
• Every variation order approved in writing before execution. This approval covers the scope description, reason for change, cost impact, and schedule impact if any.
• Periodic progress reports that list variation orders currently being proposed, so there are no surprises at the end of the project.

This approach aligns with the stages described on the process and safeguards page, where each phase ends with an approval point before moving to the next.

How to review a variation order submission

When you receive a variation order proposal, here are a few things worth checking:

1. Is the reason for the change explained specifically, rather than a generic statement like "field adjustment needed."
2. Is the cost calculation broken down by item, consistent with how the original RAB was prepared.
3. Is there supporting documentation, such as photos of site conditions or revised drawings.
4. Does this change affect the schedule, and if so, what is the estimated adjustment.

A more complete guide on reading budget documents is available at understanding RAB: how to read a construction budget.

How early design reduces the frequency of variation orders

Many variation orders actually stem from a design that was not fully resolved before construction began, rather than from truly unforeseeable site conditions. The more detailed the working drawings, material specifications, and coordination across disciplines (structure, mechanical-electrical, interior) are finished during the technical development stage, the smaller the chance of discovering inconsistencies during execution.

This is one reason projects that design with the budget in mind from the start tend to be more stable. You can read more in designing a home that fits your budget from the start.

Frequently asked questions

Does a variation order always mean the budget will increase?

Not necessarily. A variation order can be an addition or a reduction of work. What matters is that each change is calculated and approved before execution, so its impact on the budget can be tracked from the start rather than discovered only at the end of the project.

Who submits a variation order?

It can come from the contractor upon finding different site conditions, or from you when you want to change specifications or layout. Both are valid as long as they go through the same written approval process.

Can variation orders be avoided entirely?

It is difficult to guarantee this fully, especially in renovation projects involving demolition of existing structures. However, their frequency and impact can be reduced through thorough site data collection early on and well-developed working drawings before construction begins.

If you are planning a renovation or new home construction and want to understand how variation orders will be managed in your project, start by requesting an initial project review. Our full renovation service includes this mechanism from the planning stage onward.