Homeowner Guide
Who should not get a garage floor coating in Metro Detroit?
You should not coat a Metro Detroit garage while the slab is leaking, heaving, salt-rotten, painted, or still a new pour under 28 days, because freeze-thaw, road salt, and vapor on 1940–1980 concrete will peel a film that had no right to go down, and the honest next step is drainage, slab work, or waiting—not a prettier failure.
This page is a list of nos. Each section is a situation, why it fails in Michigan, and what to do instead. It is not a funnel back into a coating.
If none of these apply, read the cost and problems guides, then quote a grind-first polyaspartic system.
Should I coat a garage that still takes on water?
No. Active leaks and MVER at or above 4.0 lbs / 1,000 sq ft / 24 hr without mitigation are a stop, not a color choice.
Situation: water tracks in from the apron, a downspout dump, or the slab reads at or above 4.0 lbs. Why it fails in Michigan: freeze-thaw turns trapped moisture into lift. 1940–1980 bays often have no vapor barrier, so the vapor does not “dry out” after you close the door.
What to do instead: fix grading and drainage, then retest MVER. If the number stays high, the path is a moisture barrier or no decorative film. Do not roll epoxy over a wet slab in January.
Should I coat a garage slab that heaves or is salt-rotten?
No. A coating cannot stitch a slab that is moving or that has lost its surface to chloride.
Situation: corners lift, the control joint has a step, or the surface is a salt-scaling network across most of the bay. Why it fails in Michigan: freeze-thaw and road salt keep working under any film you put on rotten paste.
What to do instead: talk to a concrete contractor about patch, overlay, or replace. A flood coat only belongs after the failed surface is gone and more than 50% pitting has a repair plan—not as a mask on a heaving slab.
Should I coat over paint or a warehouse-store kit?
No. Unknown paint and DIY epoxy get 100% removal. There is no skim-and-recoat on a mystery film.
Situation: you want a new flake look over last year’s kit. Why it fails in Michigan: hot tires and chloride find the weak intercoat. The published rule is strip to bare concrete.
What to do instead: budget removal. Calculator coating-removal adders are $1–$2 / sq ft extra, then a full system in the $5–$12 / sq ft range. Do not add another kit on top.
Should I DIY epoxy in a January garage?
No. Conventional epoxy wants a 50°F–90°F substrate. A cold Michigan slab stretches cure and invites amine blush and hot-tire pickup.
Situation: you bought a kit in January because the bay is empty. Why it fails in Michigan: the slab is often below the epoxy window even when the air feels “fine.” Soft films then take hot tires in March.
What to do instead: wait for a substrate in the epoxy window, or use a system actually rated for cold. Polyaspartic on this site is published at about 35°F to 100°F+ with the right kit. That is still a contractor install with a grind, not a weekend roll-on.
Should I coat a garage that was poured last month?
No. New concrete is typically 28 days or more before coating, and it still needs an MVER test.
Situation: builder just finished the bay and you want flake before you move in. Why it fails in Michigan: leftover moisture and outgassing blow pinholes, then freeze-thaw opens them.
What to do instead: wait the 28 days, test MVER, and only then grind to CSP 2. If the reading is at or above 4.0 lbs, barrier first.
Should I coat over a crack I can put a finger in?
No. A decorative film is not structural repair.
Situation: a wide crack, a settled joint, or a slab that moves when a truck parks. Why it fails in Michigan: freeze-thaw keeps working the joint. The coating will telegraph or split.
What to do instead: a concrete or foundation trade for the movement. Hairline cracks can be part of a coating repair plan after the slab is stable. A finger-width crack is not a flake color problem.
What do people ask when they should not coat the garage?
No. Active water is a drainage and slab problem. A moisture barrier is for vapor readings at or above 4.0 lbs after leaks are controlled, not a substitute for a downspout that dumps on the apron.
If the paste is rotten or the slab heaves, it is a no for a decorative coating. If the field is pitted but stable, a flood coat after prep is a possible path when more than 50% of the field shows that network—not a roll-on over scaling.
Unknown epoxy is 100% removal to bare concrete on this site. Skim-and-recoat on a mystery film is how hot tires and chloride peel the new layer. Removal calculator adders are $1–$2 / sq ft extra.
For conventional epoxy, yes, if the slab is outside 50°F–90°F. Cold concrete stretches the 3–7 day drive-on window and raises blush risk. Polyaspartic is published at about 35°F–100°F+, which is a different chemistry, not permission to skip the grind.
Typically under 28 days. Coat sooner and you fight outgassing and moisture. Test MVER even after 28 days, especially on Metro Detroit pours with no vapor barrier.
Fix water, replace rotten concrete, wait on a new pour, or strip the old film. Those are other trades or other steps. A coating quote belongs after the slab is a candidate, not as a cover for the problem.