What is a subcontractor in construction? It is the specialist trade that actually builds most of a project. On a typical commercial job, the general contractor manages the work and self-performs little of it, while dozens of subcontractors handle each trade. This guide explains how subcontractors fit into a project, the main types, the contract terms that matter most, and how subs price and win work.
How this guide was prepared: written and reviewed by the Design Estimation estimating team, led by founder Austin Smith (7+ years in construction estimating) and backed by ASPE Certified Professional Estimators. Contract rules and rates vary by state and project.
Subcontractor vs. General Contractor
| General contractor | Subcontractor | |
|---|---|---|
| Contract with | The owner | The general contractor (or another sub) |
| Responsible for | The whole project, schedule and coordination | Its own scope of work |
| Typical work | Management, general conditions, some self-performed trades | Specialist trade work: concrete, MEP, roofing, finishes |
| Gets paid by | The owner | The general contractor |
| Estimates | The full project by CSI division | Only its trade, from its own takeoff |
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Types of Subcontractors
- Specialty trade subcontractors: licensed trades such as electrical, plumbing, HVAC and fire protection.
- Supply-and-install subcontractors: buy the materials and install them, such as roofing, drywall and flooring.
- Labor-only subcontractors: provide crews while the GC or owner supplies materials.
- Sub-subcontractors (lower tiers): hired by a subcontractor, such as an insulation installer working for a mechanical sub.
- Individual subcontractors: self-employed tradespeople working as independent contractors rather than employees.
Subcontract Terms Every Sub Should Understand
| Term | What it means |
|---|---|
| Scope of work | Exactly what the sub must furnish and install; the source of most disputes |
| Flow-down clause | Passes the GC’s obligations under the prime contract down to the sub |
| Pay-when-paid / pay-if-paid | Ties the sub’s payment to the owner paying the GC; enforceability varies by state |
| Retainage | A percentage of each payment held back until completion, commonly 5% to 10% |
| Insurance requirements | Certificates of insurance and additional insured status for the GC and owner |
| Bonds | Performance and payment bonds, often required on public and large private projects |
| Change orders | The process and pricing rules for added or changed work |
| Lien rights | On private projects, unpaid subs can usually file a mechanic’s lien; on public projects they claim against the payment bond instead |
Contract rules differ by state and project, so have subcontract agreements reviewed before signing.
How Subcontractors Win Work
- Receive an invitation to bid from a GC, with drawings, specifications and a bid date.
- Take off the quantities for their trade from the drawings.
- Price material, labor and equipment, then add overhead and profit.
- Write inclusions, exclusions and qualifications so the GC knows what the price covers.
- Submit the bid on the GC’s form, acknowledging all addenda.
Many trade contractors outsource step 2 so they can bid more jobs. Our subcontractor estimating services deliver trade takeoffs in 24 to 48 hours.
Advantages and Risks of Subcontracting
| For the GC | For the subcontractor |
|---|---|
| Advantage: specialist skills without permanent staff | Advantage: steady work from repeat GCs |
| Advantage: fixed trade prices reduce cost risk | Advantage: focus on one trade and build efficiency |
| Risk: stays liable to the owner for the sub’s work | Risk: payment delays, retainage and pay-if-paid clauses |
| Risk: schedule depends on many separate companies | Risk: scope gaps in the bid become unpaid work |
Frequently Asked Questions
Quick answers about subcontractors in construction.
What is a subcontractor in construction?
A company or individual hired by the general contractor to perform a specific part of the project, such as electrical, concrete or drywall, under a subcontract agreement.
What is the difference between a contractor and a subcontractor?
The general contractor contracts with the owner and manages the whole project; the subcontractor contracts with the GC for one scope of work.
Who pays a subcontractor?
The general contractor pays the subcontractor, usually through monthly progress payments, minus any retainage.
What is retainage?
A percentage of each payment held back until the work is complete, commonly 5% to 10%, depending on the contract and state law.
Is a subcontractor an employee?
No. A subcontractor is an independent business that controls how it does the work and handles its own taxes and insurance.
How do subcontractors estimate their work?
They take off quantities for their trade from the drawings, price material, labor and equipment, then add overhead and profit. Many outsource the takeoff to save time.
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