Siding Allowances vs. Change Orders

Two contracts for the same siding job can carry the same headline price and behave completely differently once the crew opens the first wall. The difference is in how they handle the unknown. This guide covers what an allowance is, what a change order is, when each is the right tool, and the specific wording worth insisting on before you sign.

The problem both tools exist to solve

Siding hides the wall. Until the old cladding comes off, nobody — however experienced — can tell you exactly how much of the sheathing beneath it is sound. On an older Sacramento or Bay Area home, some amount of damage is likely; how much is genuinely unknown.

A contractor has three ways to handle that. They can guess high and carry a padded price, which makes them look expensive against bidders who did not. They can guess low or ignore it, then raise change orders once the wall is open. Or they can carry a stated allowance with an agreed unit price, which is the honest version. Understanding the difference lets you tell those three apart while you are still comparing bids.

What a good allowance looks like

An allowance is money inside the contract price, set aside for foreseeable work of unknown quantity. To be worth anything it needs three components:

• A defined scope. Precisely what the allowance covers — for example, replacement of damaged wall sheathing, but not framing repair, which is a separate item.
• A quantity and a unit price. "Includes replacement of up to 12 sheets of sheathing; additional sheets at $X per sheet installed." This is the part that matters most, and the part most often missing.
• Two-way reconciliation. Under-use is credited back to you; over-use is billed at the stated unit price. Both directions, stated explicitly.

An allowance with no quantity and no unit price is not an allowance. It is a number in the bid that will be resolved later, in a conversation you will not be well positioned for.

What a good change order looks like

A change order handles work genuinely outside the original scope — you decide to replace the windows too, or the wall turns out to need structural repair nobody could have anticipated. It should always contain:

1. A clear description of the additional work.
2. The price, and how it was derived — agreed unit rates, time and materials with stated rates, or a fixed sum.
3. Any impact on the schedule.
4. Signatures from both parties, dated, before the work is performed.

The sequence is the whole point. A change order signed after the work is done is not an authorization, it is an invoice with a signature line.

Side by side

That last row is the practical argument for pushing foreseeable work into allowances. Your negotiating position is never better than it is before you sign.

The moment they meet: rot behind the wall

Here is the scenario that generates most of the disputes we hear about. The crew pulls the old siding on a 1970s home and finds dry rot at the sill and around two window openings. What happens next is decided entirely by paperwork signed weeks earlier.

With a proper allowance, the damage is measured, applied against the allowance quantity, and any excess billed at the agreed unit rate. There is a number, it was agreed to, and the crew keeps working.

Without one, everything stops for a pricing conversation you are having under pressure, with your house open to the weather and a crew standing on site. Some of that pressure is real and some of it is leverage, and it is very difficult to tell which is which from where you are standing.

For what rot behind siding actually looks like and why it is so common here, see preventing water damage behind siding.

Red flags in either

• An allowance with no quantity or no unit price attached.
• Allowance language that only ever adjusts the price upward.
• A contract with no allowance for substrate repair at all on an older home — this is not optimism, it is deferral.
• A change-order clause permitting verbal authorization.
• Time-and-materials pricing for discovered work with no stated hourly rate or markup.
• No named person with authority to approve changes on either side.
• Any suggestion that paperwork can be caught up later. It is never caught up later.

What to ask before signing

1. What allowances are in this contract, for what scope, at what quantity and unit price?
2. If we come in under an allowance, how is the credit returned to me?
3. What unit rates have we agreed for the discovered work you would most expect to find on a house this age?
4. Who has authority to sign a change order, on both sides?
5. What is the process if something is discovered that genuinely cannot wait for a signature?

A contractor who answers all five easily has run these projects before. For the wider bid comparison, see our guide to comparing siding quotes in California and what to ask before signing a contract.

How Heritage Exteriors handles it

Heritage Exteriors (CSLB #1055919) carries a stated substrate-repair allowance with a unit price on re-siding work where the wall condition is unknown, reconciles it in both directions, and does not perform additional work without written authorization. To get a scoped estimate on your home, request a free estimate or call (916) 546-2991.

Reviewed August 2026. This is general guidance on contract structure, not legal advice — have your contract reviewed by your own attorney before signing.