1. Ask for the full street address in writing. Not a phone conversation, not a verbal answer on-site — text or email. A legitimate contractor gives you a number, a street, a city, and a ZIP in under a minute. Hesitation, deflection, or "I'll send it later" is your first data point.

2. Paste that address into Google Maps and switch to Street View. You're checking one thing: does the address correspond to something that could plausibly house a business or a working tradesperson? A commercial unit, a warehouse, a residential home used as a base — all fine. A UPS Store, a strip-mall mailbox center, or an empty lot is not.

Cross-check the address against public records

3. Search your state's Secretary of State business registry (search "[your state] secretary of state business search"). Type in the company name. A real business will list a registered agent and a principal address. Compare it to the address they gave you. Mismatches aren't automatically fatal, but they need an explanation.

4. Check the address on your county or city business-license lookup. Most municipalities require a licensed contractor to register a physical business location. If the license lists a different address — or no license appears at all — ask why.

5. Run the address through the USPS ZIP lookup tool (tools.usps.com). If USPS classifies the location as a "Commercial Mail Receiving Agency" (CMRA), that's a mailbox rental — a PO Box wearing a costume. This one check alone catches the most common trick.

A CMRA address looks exactly like a real suite number. The USPS tool is the only fast way to tell a 'Suite 200' apart from 'Mailbox 200.'— Common tip from construction fraud investigators

Confirm they actually operate there

6. Call the number listed with the business registration — not the cell number they gave you. See if it connects to the same company and whether anyone answers as the business.

7. Ask a direct question: "Can I stop by your shop or office to sign the contract?" You don't have to actually go. You're watching the reaction. A contractor with a real location says "sure." A contractor without one suddenly prefers to meet at your house or a coffee shop.

8. Request a piece of mail or a document tied to the address — a business insurance certificate (COI) or a utility bill. The COI will list the insured's address. If it matches, you've now confirmed the location through a third party who has money on the line.

Put it in the paperwork

9. Write the verified physical address into the contract itself, in the party-identification section. This matters if you ever need to serve legal papers or file a mechanic's lien dispute. "You can't sue a PO Box" is close enough to true that it should change how you draft the agreement.

10. Save every screenshot: the Street View, the Secretary of State page, the USPS classification result, and the COI. Ten minutes of saving now is the difference between "I know where they are" and "I have no idea who I paid."

The one red flag that shows up in almost every bad hire

The contractor only has a cell phone and a mailbox — no fixed physical location they'll let you verify. Every other warning sign tends to follow from this one. Someone with no address to defend has nothing to lose by disappearing.

If you'd rather skip the detective work entirely, start with contractors who've already been vetted and who agree to hold your money in escrow until the work is done. When payment is tied to completion, vanishing stops being an option.