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Change Orders: Why Renovation Budgets Move, and How to Write a Contract That Controls Them

Overruns are not weather. Every one of them was written down at the time, on a piece of paper called a change order.

Fixer Upper Pros editorial team · Updated September 2026

Budgets do not drift, they get changed

Every renovation that finishes over budget finished over budget for a reason that was written down at the time. That document is the change order. If you understand the four things that generate change orders, and you write a contract that forces each one through a controlled process, you will not eliminate overruns, but you will stop being surprised by them.

The four sources of a change order

1. Unknown conditions

Demolition reveals what the drawings could not: rot at a sill plate, knob and tube wiring in a wall that was supposed to be untouched, a drain line running exactly where the new island goes, a chimney chase nobody knew was there. On a house older than about 1980, assume at least one of these. This is nobody's fault and it is the reason a contingency exists.

2. Owner initiated changes

You see the framed room and decide the window should be a foot wider. Entirely your right, and entirely your cost, and the cost is not just the window. It is the header, the siding patch, the interior trim, the paint, and the two days the framer has to come back.

3. Allowance overruns

The tile you chose costs more than the allowance assumed. These are the most predictable overruns and the easiest to prevent, by making your selections before the contract is signed rather than during construction.

4. Code and inspector driven upgrades

The inspector requires hardwired smoke detectors throughout, or an arc fault breaker, or a larger header than the drawings showed. These are not optional and not negotiable.

What a real change order contains

A text message saying "the extra window will be about two grand" is not a change order. A change order is an amendment to your contract, and it should carry all of the following:

• A sequential number and a date.
• A description of the changed work, specific enough that a stranger could price it.
• The reason: unknown condition, owner request, allowance adjustment, or code requirement.
• The cost breakdown, showing labor, material and the markup applied, not a single lump number.
• The schedule impact in calendar days, including zero if there is none.
• The new revised contract total.
• Signatures from both parties, dated, before the work is performed.

That last point is the whole game. A change order signed after the work is done is not an approval, it is an invoice.

Contract language that actually controls cost

Ask for these clauses before you sign. Most reputable contractors already use some version of them, and the ones who object to all of them are telling you something.

• Written change orders required. No change in scope or price is binding unless documented and signed by both parties in advance. Verbal directions are not authorization.
• A markup cap on change order work. Overhead and profit on change orders is applied at a stated percentage, the same one used in the base contract. Without a cap, change order work often gets priced at a much richer margin than the original scope.
• Unit prices for the likely unknowns. Agree in advance on a per linear foot price for sill plate replacement, a per square foot price for subfloor replacement, a per outlet price for new circuits. When the wall opens, the argument is about quantity, which is measurable, rather than price, which is not.
• Allowance reconciliation. Unused allowance funds are credited to the owner on the final invoice. Overruns are billed at cost plus the stated markup and require a signed change order.
• Schedule impact stated per change order, so that a $900 change does not silently become a two week delay you find out about at the end.
• A stop work provision. If work outside the signed scope is performed without an approved change order, the owner is not obligated to pay for it.

Carry a contingency, and treat it as real money

A reasonable contingency on a cosmetic renovation is about 10 percent. On a gut renovation of an older home, or anything that opens walls and floors, 15 to 20 percent is the honest number. Hold it in your own account, not the contractor's. It is not part of the contract sum, it is your reserve for the change orders you cannot foresee.

The practical test: if a $2,500 unknown condition would force you to stop the job, your budget is not the contract amount, it is the contract amount plus a reserve you do not have.

How to run the process week to week

Set a standing weekly meeting on site, same day and time, with the person who actually directs the crew. Fifteen minutes is usually enough. Three questions:

1. What was completed since last week, and what is scheduled for next week?
2. What decisions do you need from me, and by when? Selection delays are one of the largest hidden costs in remodeling, because they idle a crew that is already scheduled.
3. Is anything on the horizon that could become a change order?

Then follow the meeting with a short email summarizing what was said. You are not building a legal case, you are building a shared record, and a shared record is what keeps a disagreement in month four from becoming a dispute.

When to say no

Not every proposed change deserves approval. Ask what happens if you decline. Sometimes the answer is a genuine code or safety requirement and there is no choice. Often the answer is that the upgrade is nice but optional, and the honest contractor will say so. You are allowed to take three days to decide on anything that is not blocking the crew, and you are allowed to ask for a second price on a large change.

Budgets move on every renovation. The difference between a project that ends at 8 percent over and one that ends at 40 percent over is almost never luck. It is whether every dollar had to walk through a signed piece of paper on its way out.

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