A home addition can add thousands to your property value—but only if you hire the right contractor. Vetting builders carefully protects you from cost overruns, structural disasters, and projects that drag on indefinitely. Here's what to watch for.
No Clear Written Estimate
If a contractor gives you a ballpark figure over the phone or a vague estimate on a napkin, walk away. A legitimate builder provides a detailed, itemized estimate that breaks down labor, materials, permits, and contingencies. For a typical room addition (200–400 sq ft), expect estimates between $25,000 and $80,000 depending on region and finishes—and that estimate should list what's included.
Red flags include:
- Estimates missing labor costs or material specifics
- Refusal to put the estimate in writing
- Drastically lower quotes than competitors (often signals corner-cutting ahead)
- No mention of permit costs or timelines
Lack of Verifiable References and Licensing
Ask for at least three completed addition projects you can contact directly. Call those homeowners and ask about timeline adherence, final costs versus estimates, and whether punch-list items were actually completed.
Check your state's contractor licensing board online—most states maintain searchable databases. Verify the contractor's license is current and look for complaints. A few minor resolved complaints are normal; multiple unresolved disputes or license suspensions are not. If they claim they "don't need a license," don't hire them. Most jurisdictions require licensing for home additions.
Unwillingness to Pull Permits
A contractor who says permits are "expensive" or "unnecessary" is cutting corners on a fundamental level. Unpermitted work voids warranties, complicates future home sales, and fails inspections. Building permits for additions typically cost $500–$2,000 depending on project scope and location, and they exist to ensure structural safety and code compliance.
Legitimate contractors factor permit costs into their bid upfront. If they resist, that's a sign they'll resist other safety standards too.
Requesting Full Payment Upfront
Never pay the full amount before work starts. Standard payment schedules for additions look like this: 25–33% down to secure materials and scheduling, periodic payments as milestones are hit (foundation poured, framing complete), and a final 10–15% holdback until final walkthrough and punch-list completion.
A contractor demanding 50% or more upfront is either financially unstable or running a high-risk operation. If they go under mid-project, you've lost that deposit with no recourse.
Vague or Non-Existent Timeline
"Sometime next spring" isn't a timeline. A professional addition contractor provides a start date, estimated duration, and key milestone dates. Most room additions take 4–8 weeks from permit approval to substantial completion, though this varies by size and complexity.
Get the timeline in writing. Include provisions for what happens if the contractor causes delays versus weather delays versus permit delays—these have different implications for your budget and schedule.
No Insurance or References to It
Ask for proof of general liability insurance and workers' compensation coverage. Call the insurance company directly to verify the policy is active. If a worker is injured on your property and the contractor is uninsured, you could be liable. Insurance costs are built into professional estimates; it's non-negotiable.
Poor Communication or Unprofessionalism
How a contractor communicates during the sales phase is how they'll communicate during the project. Red flags include:
- Takes days to return calls or emails
- Defensive when you ask questions
- Dismissive about your design preferences
- No written contract or proposal
A trustworthy contractor is responsive, collaborative, and thorough in writing.
Frequently Asked Questions
Q: What should I do if a contractor's estimate is 30% lower than others? Ask specifically what's excluded or cheaper. Sometimes lower costs reflect efficiency or buying power; sometimes they reflect skipped steps or low-quality materials. Get itemized comparisons and verify the contractor's licensing and references before assuming it's a good deal.
Q: How do I know if a contractor will actually follow the timeline? Request a detailed project schedule with start date, completion date, and interim milestones. Include contractual penalties or compensation terms if the contractor causes delays, and clarify which delays (weather, permit hold-ups) are outside these terms.
Q: Can I negotiate the contract terms, or should I accept what the contractor offers? Absolutely negotiate. Key items to adjust include payment schedule, timeline penalties, warranty length, and who handles permit applications. A contractor unwilling to negotiate reasonable terms on these points may be inflexible about quality or safety concerns too.
Use Mercoly to compare and find trusted home addition contractors in your area, read verified reviews, and get multiple estimates in one place—saving time and protecting your investment.