You pull the first course of old siding off a house and the sheathing underneath crumbles like wet cardboard. The homeowner is standing right there. You say, “We’ll take care of it,” and you keep working. Three weeks later the job is done, the check is short, and you are eating four sheets of OSB, two days of labor and a pile of flashing. That is how siding change orders go wrong, and it happens on small repair jobs and full re-sides alike.
Siding is a trade where the real scope is hidden behind the product you are selling. You bid what you can see. The wall tells you the rest after the old material is off. If you do not have a signed change order for what you find, you have a free-work problem and sometimes a client-trust problem on top of it.
This article is general information about contracting practice, not legal advice. Contract rules vary by state, so check your own contract and local requirements.
What an unsigned siding change order really costs
Run the numbers on a typical re-side. Say you find rot on three walls. That is 12 sheets of sheathing, a day and a half of a two-man crew to cut out and replace it, plus extra fasteners, sealant and flashing tape. Even at modest rates that is easily a four-figure hit. Do the same thing on two jobs a month and the loss stacks up fast.
The money is only the first bill. The second is the argument. When you finally raise the extra charge at the end of the job, the homeowner hears a surprise. Surprises on a final invoice are what turn into chargebacks, bad reviews and holdbacks on your last payment. The scope you never wrote down gets argued from memory, and memory always favors the person who is paying.
The third bill is schedule. Waiting on an answer about extra work while a house sits wrapped in Tyvek is a weather risk for you, not the owner. If rain comes in on exposed sheathing, who pays for that? Without a paper trail, you probably do.
Mistake 1: Treating hidden rot as part of the bid
Most siding contracts cover installing new siding over a sound wall. Rot, insect damage and failed flashing are conditions nobody could price from the driveway. Yet contractors regularly absorb them because the conversation feels awkward in the moment.
The fix is simple. Put a line in your contract that says concealed damage found after removal will be priced as a change order, ideally at a unit rate such as a price per sheet of sheathing or per linear foot of trim. Then when you find it, you are not negotiating from scratch. You are pointing at a number the owner already saw. For more on this, see our guide to hidden damage change orders.
Mistake 2: Letting the color or profile change on a handshake
Siding is a visible, personal choice, and owners change their minds. They see the first few boards up and decide the lap is too wide, or the color looks darker than the sample. If you swap the order on a verbal okay, you may end up with a restocking fee, a special-order lead time and an owner who later says they never approved it.
Any change to color, profile, texture, trim package or manufacturer is a change order, even if the price comes out the same. Write down the product, the color name and the lot or order number. If the material is already cut or installed, say so on the form. A one-page signed change order is cheap insurance against the single most common siding fight: “that is not what I picked.”
Mistake 3: Ignoring house wrap, flashing and trim details
Installing siding over a poor water-resistive barrier is a callback waiting to happen. Window and door flashing that was never done right, missing kick-out flashing at roof lines and old trim that cannot be reused all show up once the wall is open. Fixing them is real work, and it is not what the original number covered unless you said it was.
When you see a flashing or wrap problem, take photos, write up the fix and price it before you cover it back up. If the owner declines the repair, have them sign that decision. That signature protects you if moisture shows up later. Related window issues are covered in our post on window and door change orders.
Mistake 4: Skipping the sign-off on extra wall area
Takeoffs are tight. Then you discover the gable on the back of the house, a dormer that was not on the plans or a bump-out the owner forgot to mention. Extra square footage is the cleanest kind of change order because it is easy to measure and easy to price. It is also the easiest to leave off the invoice when you are busy.
Measure, write the added squares, multiply by your installed rate, and get a signature before the crew starts that wall. That takes five minutes with a clear form. If you prefer working in a spreadsheet, the free Excel change order template calculates the line items, markup and revised contract total for you.
Grab the free Excel change order template
A professional, auto-calculating change order spreadsheet — line items, markup, tax and your revised contract value all worked out for you, plus a log to track every change order on the job. Free to download and use on any project.
Download the free Excel template →Mistake 5: Eating material price swings and long lead times
Fiber cement, engineered wood and vinyl all have lead times that can slip. Supplier pricing can change between your bid and your order. If your contract does not say how price changes and delays are handled, you carry that risk by default.
Add a clause that lets you adjust for material price changes and write a change order when the owner switches to a product with a longer lead time. If the delay pushes your crew off the job and onto a later start, record that too. Our guide to material price increase change orders walks through how to word it.
Mistake 6: Letting the change order lag behind the work
The biggest mistake sits under all the others: doing the work first and papering it later. When the paperwork comes after the labor, the owner holds the upper hand. They can negotiate the price down because the work is already done. They can also dispute that they ever asked for it.
The rule that protects you is boring and works: no extra work starts until the change order is signed. If that feels slow on a busy wall, the answer is a faster way to send it, not skipping it. With the free digital change order tool, you can fill in the change on your phone and have the owner sign from theirs, so the crew is not standing around waiting for an answer.
A simple siding change order checklist
Use this on every siding job, and the surprises get a lot cheaper:
- Describe the change in plain words. “Replace 6 sheets of rotted 7/16 OSB on the north wall” beats “extra prep work.”
- Attach photos. Photos of rot, missing flashing or damaged trim end most arguments before they start.
- Price it separately. Break out labor, materials and markup so the owner sees where the number comes from.
- State the schedule effect. If it adds a day or two, write the new completion date.
- Get a signature before work starts. A text or email approval can work as a record, but a signed document is better.
- Keep a running log. Track every change order against the job so the final invoice matches the paper.
The right way to handle siding change orders
Good siding contractors do not avoid surprises. They price them before they happen. They put unit rates for concealed damage in the contract, they document every field change and they refuse to start extra work on a promise. Both of the free options on this site make that routine.
If you like working in a spreadsheet, download the free change order spreadsheet, fill it in and send it as a PDF. If you want the owner signing from a phone while you are still standing at the wall, create a free change order online. Either way it costs nothing, and you can read why it is free. For more guides like this, browse the ChangeOrdersPro blog, or read about change order scope creep.
Skip the Word doc. Send it in 30 seconds.
ChangeOrdersPro turns this into a 30-second job — fill in the change, hit send, and your client signs from their phone. The contract total updates itself. It’s 100% free.
Create a free change order →Siding is a visible, high-dollar part of the house and owners care about it. A clear process is how you protect your margin and keep the relationship intact at the same time.
Frequently asked questions
Do I need a change order for rotted sheathing found during siding removal?
Yes. Concealed damage is outside the scope you bid, so write it up as a change order with a clear description, photos and a price before you repair it. A unit rate in your original contract makes this much easier.
What if the homeowner changes the siding color after it is ordered?
Treat it as a change order. Record the new product and color, any restocking or reorder cost and the effect on the schedule, and get it signed before you place the new order.
Is the free Excel change order template good for siding jobs?
Yes. It handles line items, markup, tax and your revised contract total, so you can list sheathing, trim and added wall area separately. You can download it free from the template page and use it on any project.
Can I send a siding change order from my phone?
Yes. The free digital tool lets you fill in the change and send it to the client, who can sign from their phone, so work is not held up waiting on paperwork.
Is this legal advice?
No. This is general information, not legal advice. Requirements change and vary, so confirm the current rules with your state's licensing board or a licensed attorney before relying on them.
Daisy writes about the unglamorous side of running a build — the paperwork, the change orders, and the conversations that keep a job profitable. ChangeOrdersPro is the free tool her team built so contractors can send a professional change order and get it signed from a phone in about 30 seconds.