Getting a general contracting estimate for a home addition or major remodel doesn't have to feel like guessing in the dark. The difference between a solid bid and an inflated one often comes down to how detailed your request is and how thoroughly you vet the contractors you're asking.
Define Your Project Scope First
Before reaching out to any contractor, create a written description of exactly what you want done. Vague requests like "I want to add a bedroom" will generate wildly different estimates. Instead, specify dimensions (a 16×14 bedroom addition), materials (vinyl siding to match existing, or new windows with specific energy ratings), and finishes (hardwood floors, standard drywall, or premium fixtures).
If you're doing a kitchen remodel, note whether you're keeping the existing layout or moving plumbing and electrical. Relocating a sink adds $2,000–$5,000 in labor and materials alone. Moving a load-bearing wall? That's a structural engineer ($400–$800) plus reinforcement costs that can run $3,000–$8,000 depending on span.
The more specific your project description, the less room contractors have to pad estimates or interpret your needs differently.
Get Multiple Bids from Licensed, Insured Contractors
Request estimates from at least three contractors in your area. Aim for a range that includes a smaller local firm, a mid-size operation, and potentially a larger company. This helps you spot outliers and understand market rates for your region.
All contractors should be licensed for your state and carry liability insurance plus workers' compensation. Ask for proof before scheduling an estimate visit. Unlicensed work might seem cheaper upfront, but you're exposed to liens, poor workmanship, and zero recourse if something goes wrong.
General contracting for additions typically costs $150–$250 per square foot depending on complexity and your location. A basic 400-square-foot addition in a moderate market might run $60,000–$100,000; the same project in a high-cost area could easily exceed $150,000.
What to Look for in a Written Estimate
A professional estimate should be detailed, not a one-page quote with a lump sum. Here's what a solid bid includes:
- Materials list with quantities and brand names (don't accept vague terms like "quality lumber")
- Labor costs broken down by task (framing, electrical, plumbing, drywall, painting, finishing)
- Timeline with start and completion dates
- Payment schedule (typically 10% down, progress payments, final payment on completion)
- Allowances for items you haven't finalized (tile, fixtures, appliances)
- Exclusions clearly stated (permits, inspections, site cleanup, architectural fees)
If a contractor won't provide a written estimate, move on. Phone quotes and verbal agreements are how misunderstandings happen.
Compare Apples to Apples
Don't just pick the lowest bid. A $50,000 estimate that omits permit costs and final grading isn't comparable to a $65,000 estimate that includes everything. Call the low bidder and ask why they're cheaper—it might be efficiency, but it could also be that they're leaving work out.
Check whether the estimate includes:
- Building permits and inspections
- Material waste (usually 5–10%)
- Dumpster rental
- Site protection and cleanup
- Contingency markup (usually 10–15% for unexpected issues)
Ask each contractor about their warranty on workmanship. A year is standard; some offer longer.
Ask the Right Follow-Up Questions
Once you have estimates in hand, contact each contractor with clarifying questions:
- How do you handle scope changes or surprises during the project?
- What's your payment schedule if the timeline extends?
- Can you provide references from similar projects completed in the past 12 months?
- Do you manage all permits, or will I need to hire someone separately?
Check those references. Ask previous clients specifically whether the final cost matched the estimate and whether the contractor was responsive to changes.
Use a Resource to Compare Locally
If you're still in the search phase, platforms like Mercoly let you compare and review trusted general contracting providers in your area all in one place, which streamlines the vetting process.
Frequently Asked Questions
Q: How long should I expect a general contracting estimate to take after meeting with the contractor? A: Most reputable contractors deliver written estimates within 5–10 business days. If they're taking longer, follow up; delays sometimes signal disorganization or that they're overbooked.
Q: Should I accept a contractor's estimate if it's missing a contingency line item? A: No. A 10–15% contingency for unexpected issues (hidden water damage, code violations discovered mid-project) is standard practice. If they won't include one, they're either inexperienced or planning to change orders later.
Q: What's the difference between an estimate and a quote for a general contracting project? A: An estimate is an educated guess subject to change; a quote is typically a fixed price. For additions, you'll usually get estimates unless the scope is extremely simple and finalized.
Get your detailed estimates in writing, compare them carefully, and you'll hire the right contractor at a fair price.