Half the garage floors we get called to in Ellisville already have something on them. The real question is never what to put down. It is what has to come off first.
Why the first one let go is quick to explain. Resin grips concrete by reaching down into it, and whatever got rolled on had nothing to reach into, so it held by surface tension until a warm tire or a wet shoe asked it a serious question. That is the short answer and it is not the useful part of the phone call. The useful part is what happens next, because a slab with a failed finish on it is a different job from a bare one, and the difference shows up in the hours, in the dust and in what anybody can tell you before the machine has touched it. We are ten minutes up the road, so we end up on a lot of these floors, and the conversation is nearly always about removal.
Removal is the job, not a step in it
People picture us arriving, running something over the old finish for an hour and then getting on with the floor. On a thin film that is already giving up, that is close to true. On anything else it is the bulk of the day. All of it has to come off, because a new system bonded to a failing one fails on the same schedule as the one underneath it, and the only way to know you are down to concrete is to be able to see concrete right across the slab.
How long that takes has very little to do with how bad the floor looks. A coating that is still stuck is harder to get off than one that is already failing. The sheets lifting by the door come away in minutes. The two thirds of the floor that never got driven on is still gripping, and that is the part we are still working at four in the afternoon. A garage that looks half ruined is often an easy morning, and a garage with one small blister in the corner can be a long day.
A coating that is still stuck is harder to get off than one that is already failing.
Layers, and how many of them there are
The other thing that sets the length of the day is how many times the floor has already been done. Two coats of garage paint over an old sealer is three separate things to take off, and they do not come away at the same rate or by the same method. Soft films smear and load the tooling, so they come off in shallow passes. Hard brittle ones shatter and lift fast. A floor carrying one of each gets both treatments, in whatever order the slab will allow, and that is where an hour turns into three.
Now and then we find a coating that was put down properly and simply wore out, usually in a garage that gets worked in rather than parked in. Those are the good ones. The slab under them was opened up by whoever did it the first time, so once the tired layer is gone there is less in front of us than on a floor nobody ever prepared.
A test patch comes before anybody quotes it
There is no way to answer the removal question from the doorway, so we cut a patch about the size of a dinner plate, usually behind where the door swings or in the corner nobody looks at. That patch takes twenty minutes and it answers more than an hour of talking would. It shows how many layers are stacked up, whether they come away cleanly or smear, how far into the concrete the last crew got, and whether there is something in the pores nobody mentioned because nobody knew it was there.
Most of what we read is the edge of the cut. A clean step straight down to open gray concrete means one film over a slab that was never prepared, and the rest of the day is ordinary. Two or three distinct bands in that edge means somebody has been here more than once. A cut where the machine burnishes instead of biting means a sealer is sitting in the pores, and that moves the whole plan.
That patch takes twenty minutes and it answers more than an hour of talking would.
What a removal does to the day
A bare slab in a normal garage is one day of our time. A removal stretches the front of that day and occasionally pushes the back of it into a second one. Nothing at the end moves, because the cure clock belongs to the resin rather than to us, so the hours you spend waiting after the last coat are the same hours you would have waited on a bare floor.
What does change is dust and carrying. Taking a film off a slab makes far more of both than opening clean concrete does, so extraction runs the entire time and there are more bags going out to the trailer than anybody expects. If the garage shares a wall with a bedroom or a laundry, say so when you call, because sheeting that off beforehand is easy and dealing with it afterwards is not.
Where we will ask for a second day is a floor with several layers and a lot of crack work waiting underneath them, or a slab where pulling the old finish uncovers damage it had been hiding. We would rather say that at the test patch than discover it with half the garage already open and your shelving sitting on the driveway.
How to tell before you call
You can get most of the way to the answer in five minutes with a scraper and a cup of water, and it makes the first conversation much shorter.
Turn over a piece that is already loose
Lift something that is lifting anyway and look at the back of it. Gray concrete stuck to the underside means it did bond and then lost the argument for some other reason. A clean back, the same color as the top face, means it never bonded anywhere, and the rest of the floor is in exactly that condition whether or not it has let go yet.
Count the bands on a chipped edge
Find a broken edge, by the door or at a corner, and look at it sideways in good light rather than from above. One thin band is one coating. Two or three colors stacked on top of each other means the floor has been done more than once, and that is the single thing most likely to turn one day into two.
Put water on a bare spot
Where you can see concrete, tip a little water on it and watch. Concrete that darkens straight away is open and drinking. Water that beads up and sits there means something is in the pores, usually from long before the paint went on. Neither answer is bad news by itself. They are just different amounts of work.
Notice the pattern of the failure
Letting go in two tracks and nowhere else is one story. Lifting in a line along the door is another. Coming away in scattered patches across the middle of the floor with sound coating in between is the third, and that one usually means the surface was prepared unevenly rather than not at all.
What the plan looks like once we know
With the patch cut, the rest is an ordinary conversation. We can say what the removal involves, whether it is one day or two, what the slab underneath is going to need, and what you will be standing on at the end. The chip deck comes out to the house either way, so the blend gets chosen in your own garage under your own light. The fuller write-up on garage floors on Ellisville slabs covers how we read a slab before any of this starts, and the garage epoxy system page sets out what goes down once the old finish is gone. The finished floors are the fastest way to see where a second attempt ends up.
Questions about coating over a failed floor
Can you coat over what is already on there?
No. A new system bonded to a failing one fails with it, so whatever is down has to come off. On a garage that has been painted twice, that removal is most of the work in the day, which is why we cut a patch before putting a number on anything.
How much longer does a removal take than a bare slab?
Usually a few hours at the front of the day, and sometimes a second day when there are several layers or crack work hiding under them. The waiting times at the end are the same either way. The test patch is what tells us which of those you have.
What if the old coating is still stuck down hard?
Then it takes longer, which catches people out. A well bonded old finish fights the machine far more than one that is peeling, so the floors that look worst are often the quickest, and the ones that look nearly fine are the slow ones.
Cut a patch with us first
Describe what a broken edge looks like when you call and Kevin can usually tell you on the phone whether yours is a scrape job or a straightforward one. Tell us what the edge is doing and we will come cut a patch in the corner nobody looks at. Being ten minutes away is why floors in town get looked at the same week rather than next month.