Floor coatings
Epoxy floor preparation: the unglamorous work that decides whether the coating lasts.
A floor coating is a thin film sitting on a slab that has its own moisture, dust, oil and cracks. The coating usually gets the credit or the blame, but the outcome is settled well before the first coat goes down.
Reviewed 21 September 2026 by PremiumWalls operations.
At a glance
What preparation does a floor need before an epoxy coating?
The slab must be sound, clean and dry enough to hold a coating. That means testing for moisture rising through the concrete, removing dust, oil and old coatings, grinding the surface so the coating can grip, and repairing cracks and joints properly. Coatings peel mainly where these steps were skipped, and the finished floor also needs to cure fully before it's used.
Epoxy Floor Preparation: What Decides the Result
Moisture in the slab
Concrete holds and passes water, and a slab with no proper membrane below can push moisture up through it for months. A film-forming coating over that moisture blisters and lifts, often in patches. So the floor is tested before anything is specified. If moisture is a problem, its source has to be dealt with first, because no coating will hold against water that keeps coming.
Cleaning, and why the surface needs a profile
Oil, grease, dust and old coatings all stop a new coating from bonding. They're removed properly, and where oil has soaked into the concrete, that needs particular attention. The surface is then ground or otherwise opened up, so the concrete has a texture the coating can key into. A smooth, glossy or laitance-covered slab gives the coating very little to hold onto.
Cracks, joints and damaged areas
Cracks, spalled edges and holes are cut out, filled and levelled before coating, since a coating will follow every ridge and dip beneath it. Joints are treated on purpose, because they're places where a slab is designed to move. A coating that bridges a moving joint without allowing for it will crack along the line. A crack that's still moving needs a proper look before it's covered.
Why coatings peel when preparation is skipped
Peeling, bubbling and pinholes are almost always a sign that something under the coating was wrong. Dust or oil meant it never bonded, moisture pushed it off from below, or a smooth surface gave it nothing to grip. The finish itself may have been perfectly good. Cutting the preparation is the quickest way to make an expensive floor look poor within its first season.
Testing and curing before the floor is used
The coating should be checked once it's down, and the floor must be left to cure fully before it takes traffic, furniture, vehicles or spills. A coating that feels hard on the surface can still be soft underneath. Follow the maker's stated cure times for the system used, and keep the floor clear until we say it's ready. Driving a car onto a garage floor too soon is one of the commonest ways to ruin it.
Epoxy Floor Preparation: What Decides the Result — your questions.
Can epoxy go over old tiles or an existing coating?
Sometimes, if what's underneath is sound and firmly bonded, and it's prepared properly. Loose tiles, hollow patches or failing coatings need to come up first. We check the floor at inspection before saying yes or no.
Why is my garage floor peeling after coating?
The usual causes are moisture rising through the slab, oil or dust left on the concrete, or a surface that wasn't ground open. Hot tyres and early use before full cure can also lift a coating. The cause has to be found before recoating, or it will happen again.
Does a new slab need to wait before coating?
Fresh concrete holds a lot of moisture and needs time to dry before a coating goes on. How long depends on the slab and conditions, so it should be tested, not guessed. Coating too early is a common reason for blistering.
How long before we can use the floor?
It depends on the system and site conditions, and the maker's stated times are the guide. Light foot traffic and heavy loads or vehicles are usually not the same wait. We tell you when each is safe for your floor.
Let us look at your walls first.
Tell us about the property and we will set up a free colour and wall inspection. You get a written, itemised quotation afterwards, with no obligation to go ahead.
- We call you back the same day to get a picture of the property and the surfaces.
- We agree a time and come out for the free inspection.
- You get the written scope and itemised quotation.
- Nothing starts until you approve it.