Change Orders in Construction: The Complete Guide to Costs, Causes, and How to Prevent Them

Change orders in construction are one of the most common—and costly—drivers of budget overruns and project delays. What starts as a straightforward renovation or build can quickly escalate once changes to scope, materials, or conditions begin to stack up.

For homeowners, change orders often feel unexpected or even unfair. But in reality, they are a predictable and structural part of how construction projects operate. Understanding how and why change orders happen—and how to control them—is essential if you want to protect your budget and timeline.

This guide breaks down everything you need to know about change orders in construction, including what they are, why they happen, how they impact costs, and the exact steps you can take to prevent them.

What Are Change Orders in Construction?

A change order is a formal modification to the original construction contract that adjusts the project’s scope, cost, timeline, or all three. It is typically documented in writing and agreed upon by both the homeowner and contractor before the change is executed.

Change orders exist because construction projects are rarely static. As work progresses, new information emerges, decisions evolve, and unforeseen conditions arise. The change order process provides a structured way to account for these adjustments.

Quick answer: In most residential construction projects, change orders increase total project costs by 5–20% per occurrence, and multiple change orders can compound to increase total costs by 20–50% or more.

It’s important to understand that not all change orders are negative. Some are necessary to address safety issues, code compliance, or unavoidable conditions. However, many are preventable—and those are the ones that typically drive unnecessary cost overruns.

Why Change Orders Are So Common in Construction

To understand change orders, you have to understand how construction projects actually work. Unlike purchasing a finished product, construction involves assembling a complex system over time, often with incomplete information at the outset.

Several structural factors make change orders common:

Because of these factors, change orders are not random—they are the natural outcome of uncertainty, incomplete scope, and evolving decisions.

This is why preventing change orders isn’t about eliminating them entirely—it’s about reducing uncertainty before construction begins.

The 6 Primary Causes of Change Orders in Construction

While every project is unique, most change orders can be traced back to a small set of root causes. Understanding these causes allows you to predict—and prevent—the majority of changes.

1. Scope Gaps and Incomplete Project Definition

Scope gaps are the single most common cause of change orders. They occur when the original contract does not fully define what is included in the project.

When scope is unclear, contractors must make assumptions. These assumptions are often based on minimal requirements or best-case scenarios, which rarely match the homeowner’s expectations.

Example:

Once these decisions are clarified, costs increase—and a change order is issued.

Impact: Scope gaps can easily add 10–30% to a project’s cost across multiple categories.

2. Unforeseen Conditions (Hidden Issues)

Unforeseen conditions are issues that cannot be identified until construction begins. These are especially common in renovation projects.

Typical examples include:

Example:

Total impact: +42% increase

These types of change orders are often unavoidable, but their financial impact can be mitigated with proper contingency planning.

3. Design Changes and Homeowner Decisions

Many change orders are driven by homeowners making decisions during construction rather than before it begins.

This includes:

Example:

Total change: +$6,700

These changes often feel incremental but compound quickly across the project.

4. Contractor Pricing Strategy

In some cases, change orders are not accidental—they are built into the pricing strategy.

Some contractors provide lower initial bids to win projects, knowing that incomplete scope will lead to change orders later. This allows them to recover margin during construction.

This doesn’t necessarily indicate bad intent, but it does reflect how the industry often operates.

Key insight: A low bid with vague scope often results in higher final costs through change orders.

5. Code Requirements and Inspections

Construction must comply with local building codes, which may require changes during the project.

Examples include:

These changes are mandatory and can significantly impact costs.

6. Miscommunication and Documentation Gaps

Misalignment between homeowner and contractor is a frequent cause of change orders.

If expectations are not clearly documented, discrepancies can lead to rework.

Example:

Result: Double cost for the same work

Real-World Change Order Examples (Cost Breakdown)

Understanding how change orders accumulate in real projects is critical.

Example 1: Kitchen Remodel

Breakdown:

Final cost: $44,500 (+48%)

Example 2: Bathroom Renovation

Final cost: $25,200 (+40%)

Example 3: Whole-Home Renovation

Final cost: $175,000 (+25%)

These examples show how multiple small changes compound into significant overruns.

How Change Orders Drive Budget Overruns

Change orders rarely happen in isolation. Instead, they compound over time, creating a cascading effect on cost and timeline.

Typical progression:

Final cost: $63,000 (+57%)

This compounding effect is what makes change orders so dangerous. Each individual decision may seem reasonable, but collectively they create significant overruns.

How Contractors Use Change Orders (And How to Protect Yourself)

Understanding contractor incentives is critical to managing change orders effectively.

In some cases, change orders are used to:

How to protect yourself:

The more clarity you establish upfront, the less leverage change orders have later.

Fixed Price Contracts and Change Orders

Many homeowners assume fixed price contracts eliminate change orders—but this is not true.

Fixed price contracts only lock in costs for the defined scope. Any change to that scope results in a change order.

Key takeaway: Fixed price contracts reduce risk only when scope is fully defined.

How to Prevent Change Orders (Step-by-Step)

Step 1: Define Scope in Detail

Every aspect of the project should be specified, including materials, finishes, and installation methods.

Step 2: Finalize All Decisions Before Construction

Delaying decisions leads to costly changes during the project.

Step 3: Add a 15–25% Contingency Budget

This protects against unavoidable changes.

Step 4: Compare Contractor Bids Carefully

Ensure all bids include the same scope and level of detail.

Step 5: Control Change Orders Strictly

Evaluate every change carefully and understand its full impact.

Step 6: Maintain Clear Communication

Regular updates prevent misalignment.

Change Order Prevention Checklist

Final Thoughts: Change Orders Are Predictable

Change orders are not random—they are the result of decisions, assumptions, and uncertainty built into the project.

The key insight: The more clarity you create before construction begins, the fewer change orders you will face.

In construction, uncertainty is expensive. Clarity is what keeps projects on budget.