Nobody loses money on a change order they wrote. They lose it on the one they meant to write after they'd finished the work, when the client's memory of the conversation turned out to be different from theirs.
Last reviewed: August 2026 · 7 min read
The short version. Three things decide whether you get paid for extra work: it's in writing, it's signed before the work happens, and it says what it does to the schedule and the running contract total.
In California all three are effectively the law, not best practice — a change to a home improvement contract must be written and signed before that work starts, and the change order itself has to state the scope, the money, and the effect on the payment schedule.
The homeowner is standing right there. They point at the wall and say "while you're in there, can you move the outlet and add a pot light?" You say sure. Your electrician does it Thursday. Six weeks later there's a line on the final invoice for $680 and the homeowner says: I thought that was included.
They may even believe it. That's the part contractors underestimate. Two people had one conversation and walked away with two different agreements, and now the only tie-breaker is who has a document. If neither of you does, the dispute defaults to the written contract — the one that doesn't mention pot lights.
And on residential work, the paperwork isn't just leverage. It can be the difference between a collectible bill and an unenforceable one.
California is worth knowing in detail even if you work elsewhere, because it's strict and it's specific — and other states' home improvement statutes tend to rhyme with it.
Under Business and Professions Code §7159, a home improvement contract and any changes to it must be in writing and signed by both parties before the work covered by that change order begins. And §7159(d)(13) spells out what an extra work or change order has to contain:
| Required element | What that means on paper |
|---|---|
| The scope of the change | Specifically what is being added, removed, or substituted — not "misc. electrical" |
| The amount added to or subtracted from the contract price | A number, not "T&M to be determined" |
| The effect on the schedule of progress payments | Which draw this lands in, or that it's billed on its own |
The consequences of getting the contract paperwork wrong in California aren't small: a non-compliant home improvement contract can be voidable by the homeowner, and the Contractors State License Board can take disciplinary action against your license. This is one of the few areas in the business where sloppy admin is a licensing issue rather than just an accounting one.
Three of these are the California statutory minimum REQUIRED — the rest are what keeps you out of the argument in the first place.
| # | Element | Why it matters |
|---|---|---|
| 1 | Sequential CO number and date | CO-1, CO-2, CO-3. Gaps and duplicates are the first thing an opposing attorney looks for. The date proves it came before the work. |
| 2 | Reference to the original contract | Contract date and project address. Ties the change to a specific agreement so it can't be argued to be a separate, unsigned side deal. |
| 3 | Specific description of the change REQUIRED | "Relocate one 20A receptacle from the north to the east wall and add one 4" recessed LED can with wall switch" — not "electrical changes". |
| 4 | Reason and who requested it | Client request, unforeseen condition, inspector requirement, or design change. Unforeseen-condition COs get disputed most, so this line does real work. |
| 5 | Itemized amount added or deducted REQUIRED | Broken out enough to be defensible. A single mystery number invites a negotiation you already priced. |
| 6 | Schedule impact in calendar days | "Adds 3 calendar days." The line contractors skip and then regret — see below. |
| 7 | New contract total | Original + all prior COs + this one. Restate it every time so nobody is ever surprised at the end. |
| 8 | Effect on the payment schedule REQUIRED | Billed with draw 4, or invoiced separately on completion. Removes the "we'll settle up later" ambiguity. |
| 9 | Signature and date lines for both parties | Unsigned change orders are just correspondence. Both signatures, both dates. |
Say a job has a liquidated damages clause, or just a client who booked movers for the 1st. You take on four change orders and finish nine days late. Each of those COs added two or three days of work — but if none of them said so, the contract completion date never moved, and you are now late against a date you were entitled to extend.
One sentence per CO — "This change adds 3 calendar days to the contract completion date" — is the cheapest schedule protection in the business. Add the days even when the change is small and even when you think you'll make it up. Especially then.
The rule is: signature first, work second. The reality is a client texting you at 6:40am about a wall that's already open, with a framer standing there on the clock.
When you genuinely can't stop, escalate down the evidence ladder rather than dropping off it:
Change work legitimately costs more per unit than the same work bid in the base contract, and you should not apologize for that:
The clean way to handle it is to put your change order markup in the original contract. One line in the payment terms — "Change order work is priced at cost plus __%" — settles the rate while everyone's still friendly, and turns every later CO into arithmetic instead of a negotiation.
If your markup and margin numbers are fuzzy, fix that first: markup vs. margin, and the number you should actually be adding.
Nine elements, in the order they read best. Adapt it, then have your attorney check it against your state's requirements before it goes to a client.
The Change Orders tab is built around the signature-first sequence:
[CO], updates the contract total, and stamps the CO onto the Contract tab as an addendum. That's element 7 kept current automatically — and the totals don't double-count, because the CO folds into the estimate rather than sitting on top of it.Two things the app doesn't have a dedicated field for: the schedule impact in days (element 6) and the reason code (element 4). Put both in the change order's description — "Adds 3 calendar days. Requested by owner 8/6." — so they end up on the document the client signs, which is the copy that matters.
On residential home improvement work in many states, yes. California requires a home improvement contract and any change to it to be written and signed by both parties before the work in that change order starts, and requires the CO to state the scope, the amount added or subtracted, and the effect on the progress payment schedule. Requirements differ by state — confirm with your licensing board.
It's usually not a compliant change order, but it is real evidence of authorization, and it's dated. Treat it as a bridge: get the text, do the urgent work, issue the formal CO the same day and reference the text in it. Don't let the text become the only record.
Yes. Remobilization, retail material pricing, schedule disruption, and CO admin are real costs. The cleanest way is to state your change order markup in the original contract so the rate is settled before any change arises.
That's your answer about the rest of the job. A client who won't put an addition in writing is telling you how the final invoice conversation will go. Where the law requires a signed written change order, doing the work anyway can also leave you unable to collect for it — so you'd be taking the risk and the cost. Decline politely, in writing, and offer to proceed as soon as it's signed.
Per project, starting at CO-1 each time, and never reuse or skip a number within a project. A missing CO-3 invites the question of what was in CO-3. If you void one, keep the number and mark it void rather than renumbering the others.
Auto-numbered, itemized, e-signed from the client portal, and synced into the contract total the moment it's approved. 14-day free trial — $0 today.
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