Change Orders for Trade Jobs: Price Added Scope in Writing

Price a change order like a small job

A change order is a mini estimate with the same parts as the original: hours, parts and any permit or disposal. Use the same rate and the same markup you used on the base price; the rate already contains overhead, truck and profit, so nothing is added on top for them. That is similar to the order of operations in the flat-rate price calculator.

Example, on the $9,800 replacement job from the deposits guide, with a made-up change. Partway through, the tech finds failed shutoff valves, and the customer approves replacing them and adding an expansion tank. The numbers below are our examples: the shop rate is the example shop's $125.20 an hour, and the 50% parts markup is a placeholder, since there is no authoritative typical markup.

Your cost for this extra work is 2.5 hours at the example shop's $112.68 break-even per billable hour, which is $281.70, plus the $186.40 of parts: $468.10. So the change order leaves $124.50 of profit, which is 21.0% of the $592.60 price. That is higher than the shop's 10% target because the markup on parts adds to it. If you quote the parts at cost, the same extra work earns far less.

Credits count too

Scope also comes out. Say the customer drops a planned drain-pan reroute that was priced at 1 hour and $64.00 of parts. Credit it at the same rate and markup: 1 × $125.20 = $125.20, plus $64.00 × 1.5 = $96.00, so a $221.20 credit.

Net change: $592.60 − $221.20 = $371.40, which is 3.79% of the original price. Show the old total, each change with its own price, and the new total on one page. The final invoice then matches paper the customer already signed.

Update the payment schedule too

If the job runs on progress payments, a change order has to say where the money lands. Percentages invite an argument about what "50%" of a changed price means, so keep the original dollar amounts and attach the net change to one named stage. Using the deposits guide's schedule:

If a change is large or needs special-order parts, you might bill part of it when the parts are ordered, where your state's deposit rules allow it. Whether a state restricts payments taken before the work is done is a state question; the deposits guide shows how Florida, New York and Ohio treat that.

Reading the figure: the $592.60 change order is $313.00 of labor and $279.60 of parts. Its cost to you is $468.10. If the customer later refuses to pay for work nobody put in writing, that $468.10 comes out of the job's $980.00 profit (10% of the $9,800 price), which is 47.8% of it.

What some states say about changes

We did not find a national change-order rule for ordinary home service work. The rules we cite sit in state home-improvement and consumer laws, and coverage depends on the state, the kind of work and the contract size. Three examples from different regions:

• California. The Contractors State License Board's consumer guide says any changes to a home improvement contract need to be in writing, and that if the contract price needs to change, it must be done with a written change order that becomes part of the contract.
• New York. Under section 771, a home improvement contract and all amendments to it must be evidenced by a writing signed by all the parties. Section 770 covers home improvement contracts whose aggregate price exceeds $500 (warranty and maintenance-agreement work is excluded); it names heating and air conditioning equipment in its definitions and covers improvements to residential property generally.
• Ohio. The home construction service law reaches contracts above $25,000 for residential building work, as section 4722.01 defines them, and the deposits guide notes it also depends on the type of dwelling and the supplier's insurance. Its prohibited acts in section 4722.03 include charging an excess cost the owner has not approved and not giving the required estimate of excess costs. That section does not say "in writing," and cost-plus contracts are exempt from the excess-cost rules.

Notice how different the triggers are: $500 in New York, $25,000 in Ohio. A small repair may sit outside a law that reaches a remodel, and a rule written for contractors on one kind of job may not describe your kind. Your own state's licensing board, consumer protection office or an attorney can tell you what applies to you and what a change order must contain. This guide reports what those sources say; it is not legal advice.

What goes on the change order

Whatever your state requires, a change order that does its job has these items:

1. The original estimate or contract number, and a change order number.
2. What changed, in words someone who was not there can follow.
3. The price of the change, added or credited, in dollars and cents.
4. The new contract total and, if there are progress payments, the revised schedule.
5. Any effect on the finish date. A day lost waiting for a part is a fact the customer should see in writing.
6. Signatures and dates of both sides, before the changed work starts.

Do the signing fast. A tech waiting half an hour for approval costs 0.5 × $112.68 = $56.34 at break-even, so get the signature fast, with a text or e-sign link, rather than leaving the tech idle or starting on a verbal go-ahead.

Next step

Take your last three jobs and list every extra you did that was not on the original estimate. Price each one the way the first table does, then compare that total with what you billed. Write your change-order wording once, save it as a note or terms line in the estimate generator, have your attorney check it for your state, and reuse it. When the job closes, run the actual hours through the job cost calculator to see what the changes did to profit.