Why Do Contractors Use Subcontractors? (Explained for Homeowners + New GCs)
By Fabio Freire, Founder & General Contractor at EZ-Estimates. Published 2026-05-01.
Why Do Contractors Use Subcontractors?
Most general contractors do not pour their own concrete, install their own electrical, or hang their own drywall. They hire subcontractors. Homeowners often wonder why — "I am paying the GC, why are other people doing the work?"
Here is the honest answer.
The Quick Answer
GCs use subcontractors because:
- Specialization beats generalization. A licensed electrician installs faster and safer than a GC running wire occasionally.
- Capacity flexibility. A GC running 5 jobs cannot have permanent staff for every trade. Subs scale up and down.
- Risk transfer. Subs carry their own insurance and licensing. The GC pushes liability down the chain.
- Cost. A specialist sub working 40 hours a week on plumbing is faster (and cheaper per job) than a GC employee doing plumbing 2 days a month.
- Code compliance. Many trades (electrical, plumbing, HVAC) require licensed practitioners. The GC may not be licensed to self-perform.
The GC is the project manager. The subs are the execution crews.
What "General Contractor" Actually Means
A general contractor is the party legally responsible for delivering the project. They:
- Sign the contract with the homeowner
- Hold the building permit
- Schedule and coordinate all trades
- Carry insurance for the entire project
- Provide the warranty
- Manage payments and lien waivers
- Get inspections passed
- Resolve disputes
The GC is the single point of responsibility. The homeowner has one phone number to call. Everything else is the GC's problem.
Self-performing every trade would require the GC to:
- Hire 8-12 full-time tradespeople
- Carry licensing and certification for every trade
- Maintain volume of work for each trade or pay them to sit
- Carry insurance covering every specialty
For most residential GCs, this is impractical. The economics only work for very large operations (50+ employees) or very specialized GCs (e.g. design-build firms).
What Each Sub Brings to the Table
Plumber: Licensed, knows code, has the right tools (snake, pipe threader, drain machine). Bids the job, runs the job, signs off on inspection.
Electrician: Licensed, NEC code-certified. Pulls permits the GC cannot. Faster than a GC doing electrical occasionally.
HVAC tech: EPA-certified for refrigerants. Understands load calculations. Carries the manufacturer relationships for warranty.
Drywaller: Hangs and finishes drywall faster than anyone else (a 2-person crew can do 1,000 sq ft per day). Mud quality is a craft skill.
Painter: Knows paint products, prep techniques, finish quality. Has the sprayers and lifts.
Tile setter: Specialized skill (especially for shower waterproofing). Knows Schluter systems, mortar selection, layout.
Roofer: Faster, safer, and warranty-backed. Insurance for roofing is expensive — only roofers carry it.
Concrete contractor: Owns the equipment (forms, vibrators, finishers). Knows mix designs and weather-pour management.
Each sub spends 100% of their time on their specialty. The GC spends 100% of their time managing the project. Both are full-time jobs.
Why Not Just Hire Direct (Skip the GC)?
Some homeowners try this. They become their own GC and hire subs directly. It works sometimes, fails often. Here is why:
1. Coordination is the actual job.
GCs spend more time coordinating than building. When the framer leaves a wall out of plumb, the drywaller cannot fix it. The GC sends the framer back. A homeowner-as-GC has no leverage to do this — the framer has already moved on.
2. Subs do not love working for homeowners.
Subs prefer GCs because GCs:
- Have repeat work
- Pay reliably (not nickel-and-diming)
- Speak the language
- Resolve issues fast
A homeowner running their own job often gets the B-team subs (or nobody at all on tight schedules).
3. Permits and inspections.
The permit holder is responsible. A homeowner permit holder absorbs all the inspector communication, code corrections, and re-inspection scheduling. This is 5-10 hours per week of pure admin.
4. Lien risk.
If a sub does not get paid (by the homeowner), they file a mechanics lien on the property. A homeowner-as-GC who screws up a payment becomes their own enemy.
5. Schedule chaos.
Subs serve 5-10 GCs simultaneously. They prioritize the GCs they have ongoing relationships with. A one-time homeowner client gets pushed to last priority.
For projects under $10K, self-managing might work. For anything larger, the GC's coordination is worth the markup.
What Markup Goes On Subs
GCs typically mark up subcontractors 15-25%. That markup covers:
- Coordination and supervision time
- Warranty risk
- Cash flow (GC pays subs in 30 days, owner pays GC in 60-90)
- GC overhead
- Profit
This is normal. It is not the GC pocketing free money. See Why do contractors mark up subcontractors for the full breakdown.
What This Means for Homeowners
When you hire a GC:
- You are paying for coordination, not just construction
- The subs you see on site are working for the GC, not you
- Communication should flow through the GC, not directly to subs
- Quality of subs is the GC's responsibility
If you have a problem with a sub's work, tell the GC. Not the sub. The GC will fix it (or eat the cost). Going around the GC to the sub creates relationship and legal mess.
What This Means for New GCs
If you are starting out as a GC:
- Build a sub roster early. 3-5 reliable subs per major trade. Backup options for everything.
- Pay subs fast and fair. Late payments destroy sub relationships.
- Standardize the subcontractor agreement template. No handshake deals.
- Mark up consistently. 15-20% across all subs for residential. Track actual cost vs estimate.
- Charge for coordination time. It is real labor.
Tools
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