What questions should I ask a garage floor coating installer in Columbia before signing?

Columbia sits halfway between Kansas City and St. Louis on I-70, and the garage slabs in this city span more than a century of pouring practice. An East Campus bungalow built in 1908 and a Highlands pad poured in 2018 are not the same job, and the questions you ask a coating installer should reflect that. Mid-Missouri's 30-plus freeze-thaw events per winter and MoDOT's brine program on every arterial mean a generic bid does not survive contact with the actual slab. Use the questions below before anyone writes anything in chalk on your floor.

Start with the slab walk, not the number

The first question is whether the installer plans to walk your slab in person before quoting. A measurement from an aerial photo or a phone call is not a bid, it is a guess. A serious installer in Columbia asks to come to your address, look at the concrete, identify the crack patterns, and check for the contamination, salt scaling, and subgrade movement that show up so often in this market. If the first response is a per-square-foot number without a visit, that is the first red flag.

For context on what a real assessment actually covers, the guide on what goes into a garage floor coating project walks through the seven variables an honest installer considers before scoping anything. Use it as a checklist when you compare bids in Columbia.

The questions, in roughly the order they should come up

1. Will you diamond-grind the slab, or are you etching it? Acid etching is the shortcut that low-bid Columbia installers still rely on. Diamond grinding is what mechanically opens the concrete to a profile the basecoat can grip. The answer should be diamond grinding, with the grit progression matched to the slab condition. An installer who says etching is fine for an East Campus 1920s slab is selling you a coating that will peel.
2. What is the basecoat product and the topcoat product, by name and chemistry? The answer should be high-solids epoxy basecoat and aliphatic polyaspartic topcoat. Vague phrases like "industrial coating" or "premium epoxy system" without product names point to a kit-style install rebranded as professional work.
3. How are you handling moisture testing on my slab? Mid-Missouri humidity stays elevated through summer, and Columbia slabs on the silty clay loam common around Old Southwest and Benton-Stephens can carry vapor loads that destroy a coating from below. The right answer involves either a calcium chloride test or a relative humidity probe before the basecoat goes down. The wrong answer is "we have never had a problem with that."
4. What is your crack repair scope for older slabs? An honest installer differentiates between hairline epoxy injection, polyurea fill for wider cracks with ongoing movement, and structural patching for spalled perimeter zones. The freeze-thaw history on a 90-year-old slab without air entrainment is not the same as a 10-year-old pad in The Forum, and the bid should reflect that.
5. Are you Verified by the Amazing Garage Floors network, or operating independently? Verification means the crew works under a documented installation protocol with manufacturer-backed product specifications and a Limited 15 Year Warranty. Independent operators in the Columbia market range from competent to disastrous, and there is no quick way to tell which one is bidding your floor without that backing.

Warranty questions: what is actually covered

The warranty conversation is where bids diverge fast. Ask for the warranty in writing before you sign, and read what is excluded. Many low-bid Columbia warranties exclude hot tire pickup, UV yellowing, edge peeling, and moisture-related failures, which are the four most common failure modes in this market. A warranty that excludes those is a warranty on a coating that will fail and not be covered.

Specific exclusions to read for

• Hot tire pickup, which is the most common failure mode in mid-Missouri summers. See the post on hot tire marks on a garage floor for why this matters.
• UV yellowing on south-facing or west-facing garage doors, which sees direct sun through the door opening for hours per day.
• Edge peeling at the threshold, where freeze-thaw and MoDOT brine concentrate.
• Any failure attributed to "homeowner misuse" with vague definitions that let the installer disclaim almost anything.

The Amazing Garage Floors Limited 15 Year Warranty covers the coating system against defects in materials and workmanship without those carve-outs for the most common failure modes. That is the comparison standard to hold every bid against.

Process questions: what installation day actually looks like

Ask what installation day looks like start to finish. A real one-day install in a Columbia residential garage runs grinder, prep, crack repair, basecoat, flake broadcast, topcoat, all in sequence with no abbreviated steps. Ask how many crew members will be on site. Ask whether they will move your vehicles and stored items, or whether you need to clear the garage the night before. Ask what time they arrive and what time they typically finish.

Ask about return-to-service. A properly installed polyaspartic floor is walk-ready the evening of install or the next morning, and vehicle-ready in roughly 72 hours. If an installer tells you the floor needs a week to cure, they are either using the wrong chemistry or hedging against a product that does not perform.

References specific to Columbia, not generic ones

Ask for references from completed installations in Columbia or the surrounding Boone County area. A regional installer who can only point to floors in Kansas City or St. Louis has not proven their work in this specific climate and soil context. Ask whether you can drive by a completed installation in Highlands, West Boulevard, or another Columbia neighborhood and see the floor through a garage door window in person.

DIY versus professional, asked honestly

If you are still weighing a hardware-store kit against professional installation, ask the installer to walk you through the differences. A serious one will tell you honestly when DIY is reasonable, a short-term rental, a property flip, a detached shed with no UV exposure, and when it is not. The post on DIY epoxy garage floor kits covers the comparison in detail. An installer who tells you every floor must be professional regardless of use case is selling, not advising.

Insurance, licensing, and the basics most homeowners forget to ask

Ask for proof of general liability insurance before any work begins. A coating installer working in your Highridge or Westchester garage is using diamond grinders, hazardous chemistries, and curing products in your home. An uninsured operator who damages your slab or your stored property is not a problem you want to discover after the fact. Ask whether the installer is licensed to operate in the City of Columbia and Boone County, and ask whether they carry workers compensation coverage for the crew on site. A serious installer answers all three immediately. A bargain operator hedges or changes the subject.

The Columbia-specific assessment as the answer

The bid you sign should come from a verified crew that walked your specific slab, identified the prep scope honestly, named the product chemistry, and put a real Limited 15 Year Warranty in writing. Schedule the free on-site assessment, ask the questions above, and compare the answers before committing. The slab is yours for the rest of the time you own the home, and getting the coating right the first time costs less than getting it right the second time after the first attempt failed.