Not every piece of work starts with a full contract. Sometimes you're mid-job and the client asks for something additional. Sometimes you're doing a small repair that doesn't warrant a full agreement. In these situations, a work authorization form is the right tool — a lightweight written approval that documents the extra work, the price, and the client's agreement to pay for it.
This guide explains what a work authorization is, when to use one instead of a change order, and the exact fields that make it enforceable.
Work Authorization vs. Change Order vs. Full Contract
These three documents get confused, but they serve different purposes:
| Document | When to use | Who signs |
|---|---|---|
| Full Contract | Beginning of a project with defined scope, price, and timeline | Client + Contractor, before work starts |
| Change Order | Addition to or modification of an existing contract scope | Client + Contractor, before extra work begins |
| Work Authorization | Standalone job outside an existing contract, or small additions mid-project that don't need a full CO | Client, before work begins |
Think of a work authorization as a mini-contract for a specific piece of work. It has enough structure to be enforceable, but it's lightweight enough to use for a quick job without drafting a full agreement.
Common use cases:
- Emergency repair call (client calls, wants a fix, you write a one-page authorization)
- Small addition to a larger job where a full change order feels disproportionate
- Spec work or time-and-materials work where scope isn't fully defined
- Pre-bid work authorization (client authorizes diagnostic or assessment work)
- Sub work authorized by a general contractor (sub sends authorization for specific work)
The 8 Fields Every Work Authorization Needs
A work authorization that holds up has these eight elements. Missing any of them creates gaps.
1. Authorization Number
Sequential reference number: WA-001, WA-002, etc. Keeps your records organized, especially when you're running multiple authorizations on the same project or client.
2. Project Information
- Project name and address
- Client name and contact info
- Date of authorization
- If this authorization is related to an existing contract: reference the contract number
3. Description of Work to be Performed
Specific, not vague. The same standard as a change order description:
Repair water damage to drywall in master bedroom (approx. 8 sq ft area). Includes: removal of damaged drywall section, drying and antimicrobial treatment of exposed framing, installation of new drywall (matching existing texture), tape and mud (2 coats), prime and paint (matching existing: Benjamin Moore HC-172, "Blue Danube"). Client-supplied paint acceptable if provided before work begins.
What you include in the description defines what's in scope. "Fix the wall" is not a description — that's a symptom, not a scope of work.
4. Start and Estimated Completion Date
When does the work begin, and when do you estimate finishing? For emergency repairs, the start date might be "immediately upon signing" or "within 24 hours." Write it in.
5. Total Price and Payment Terms
For work authorizations, you have two pricing options depending on the work type:
Lump sum (fixed price):
Total project cost: $850
Deposit due at signing: $425 (50%)
Balance due upon completion: $425
Payment due within [X] days of invoice date.
Time and materials (T&M):
Rate: $75/hour, includes labor and standard materials.
Additional materials (beyond standard): billed at cost + 15%.
Estimated hours: [X] hours — final invoice based on actual time.
Not to exceed: $[cap] without written approval.
T&M authorizations should always have a not-to-exceed cap. Without it, you're working on an open-ended agreement that the client may dispute at invoice time.
6. Scope of Materials and Work Included
List specifically what your price covers and what it does not cover:
- Labor included (hours, tasks)
- Materials included (brand, model if applicable)
- Work EXCLUDED (what you are not doing)
- Client responsibilities (what the client must provide)
7. Warranty or Guarantee Statement
State your warranty terms for this work. Even a simple statement is valuable:
Contractor warrants this work for 30 days from completion date. Warranty covers labor and materials supplied under this authorization. Warranty does not cover damage caused by client, third parties, or natural wear.
Without warranty language, the client may expect "lifetime" coverage for a repair, which you never agreed to.
8. Client Authorization Signature and Date
Non-negotiable. The client must sign before work begins. A text message or email "sounds good" can serve as authorization in some states, but a signed work authorization is unambiguous.
By signing below, client authorizes the work described in this authorization and agrees to the payment terms stated above. Work will not begin until this authorization is signed and deposit received.
Client Signature: _________________________ Date: ________
Contractor Signature: _________________________ Date: ________
The Contractor Pack includes work authorizations, change orders, contracts, and more — everything you need for clean job documentation.
Start free — get the Change Order Form → Get the Contractor Pack →How a Work Authorization Connects to Lien Rights
This is the part most contractors miss. In most states, mechanics lien rights attach to the work described in your contract or authorization. If you do work without a signed authorization, and a dispute arises about payment, the lack of a written scope of work weakens your position significantly.
A signed work authorization proves:
- The client authorized specific work (scope established)
- The client agreed to specific pricing (price established)
- The work was performed at the client's request (not voluntary)
- The relationship was commercial, not amateur (contractor for hire)
If you need to file a lien or take the client to small claims court, a signed work authorization with specific scope and pricing is a strong document. A verbal agreement followed by an invoice is a weak document.
Work Authorization vs. Verbal Agreement — Why It Matters
The scenario: client calls you for an emergency repair. They say "just fix it, I'll pay whatever." You spend four hours and $600 in materials. They refuse to pay because "it wasn't in the original contract."
With a work authorization: you have their signature on a document that describes the work, the price, and their agreement to pay. The client can't dispute that they asked for the work and agreed to the price.
Without: you're relying on "they said they'd pay" — which is not evidence in most courts.
The cost of a work authorization: five minutes of your time. The benefit: a legally enforceable document that protects your payment.
Work Authorization Checklist — Before You Start
- Authorization number assigned (sequential)
- Project and client information complete
- Work description is specific — no vague language
- Start date and estimated completion written in
- Price is fixed OR T&M with not-to-exceed cap
- Payment terms and deposit amount stated
- Inclusions and exclusions explicitly listed
- Warranty terms stated (even if brief)
- Client signature and date obtained before work begins
- Copy provided to client (paper or email)
Related Resources
- How to Write a Change Order — companion document for scope changes on existing contracts
- Scope of Work Template — the full scope document that goes in your primary contract
- Contractor Payment Terms Template — payment language and collection terms for authorizations
- HVAC Contractor Templates — work authorization and repair authorization forms for HVAC
- Plumbing Contractor Templates — service authorization templates for plumbing professionals