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Why use a topcoat??
- Thread starter Scramblur
- Start date
AlphaGarage
Well-known member
First a couple of quick definitions... sometimes "topcoat" is used to describe the color coat of epoxy, although that's also called the body coat or base coat. Other folks use "topcoat" when the talk about the final coat, also called the clear coat. It does get tricky.
I can't speak for other systems, but our recommended system consists of 3 layers; a primer (BondTite 1101), a body coat (usually LiquaTile 1184), and a clear coat. (generally EnduraShield 2254).
We have had clients who just use a layer of LiquaTile 1184, in fact there are quite a few floors out there like that. Most of them were before we came on board as the sole Wolverine Coatings distributor for the Do It Yourself market, so I don't have a lot of info on them. I know that if they had troubles that they would eventually call us, and I haven't had any of those calls so I imagine they're holding up fairly well.
Despite that we recommend that all our clients start with a prime coat of BondTite 1101. Before that let me note that the prep work for BondTite, and almost every epoxy out there, is pretty much the same. Some manufacturers have detailed instructions, some just a page or two, but the bottom line is that prep is prep, do it right. Once the prep is done put down a primer, a coating designed to adhere not just mechanically, but also formulated to penetrate the concrete and bond chemically. In the case of BondTite 1101 we spec a 5 mil depth thickness wet. Since it's a 100% solids epoxy there won't be any shrinkage due to water or solvents evaporating, although the final dry thickness might be less due to penetration, which is fine. There doesn't need to be a lot, it's the primer coat, there just need to be enough to dons to the concrete and provide a surface for the body coat to adhere to.
We have had some clients who like to wet look of the BondTite, and just left it at that. Although usually they aim for a final coat of at least 10 mils or more to provide some durability, because although the BondTite sticks like there's no tomorrow (it's even used on steel and other metals) it doesn't provide the same wear and the durability that LiquaTile 1184 does.
It goes on next, we spec 12 mils, and since it's also 100% solids there's no shrinkage, and with the concrete sealed there's no loss there either, so if you apply 12 mils wet, you'll end up with a 12 mil thick layer after it's all cured. As I mentioned LiquaTile can be applied directly to prepped concrete, but it's not really formulated for that - it's an entirely different material. One proof of that is its weight, a 3 quart kit of BondTite weighs about 9 lbs., a 3 quart kit of LiquaTile clocks in at 11 pounds. The big difference is that LiquaTile has ceramic content, that allows it to be hard, but not brittle. As it cures the ceramic content cross-links, so it has an internal lattice, a sort if built in trampoline, which helps it dissipate shock and impact, that helps prevent concrete chip outs, scratches, dings etc.
And that brings us to the clear coat, which I think was your initial concern. On thing to remember is that all epoxies are UV sensitive, they will discolor over time. Wolverine changed the LiquaTile formulation a few months ago, and it's made a big difference in the UV stability, but it will still yellow. On the other hand the polyurethane EnduraShield is UV stable, even if used outdoors in full sunlight. That's one of the main reasons to use a clear coat - UV stability. It's also very clear, so although it filters out most of the UV, a tiny bit will still reach any underlying epoxy, but it greatly decreases the epoxy color shifting.
The clear coat also is harder, it's very hard, so it will resist scratching. It goes on thin, about 3.2 mil when cured, so it doesn't offer a lot of impact mitigation, but that's okay because the underlying LiquaTile takes care of that.
I'd look at the clear coat as a very durable sacrificial coat. In a heavy use environment you may want to to apply another coat of it in a few years after it's seen a lot of use and abuse. But it's done its job, keeping any damage from hitting the LiquaTile layer. So to freshen up the whole floor at that time is a quick and painless process, no grinding or color matching headaches, just lightly sand the clear coat and apply another layer.
If you're on a budget I'd go for a quality primer coat (since that is where almost all epoxy floor failures occur - at that junction where the first layer of epoxy contacts the concrete) and the pigmented epoxy body coat. It will scratch and get marked up easier that a clear coated system, but you'll have a system that won't lift and will protect the concrete. You can still apply the clear coat when budget allows.
If a 2 layer system is still too much, you could go for just the primer coat or just the body coat. I'd opt for the primer coat, especially if the concrete's in pretty good shape. In that case the wet look is a pretty sharp look. If the concrete is nasty looking and has a lot of patches etc., the best technical solution would again be just a quality primer coat, but aesthetically it'd be tough to choose something other than a single coat of high quality pigmented epoxy. One of those form over function calls, but with the right product one that should work out well nonetheless.
I can't speak for other systems, but our recommended system consists of 3 layers; a primer (BondTite 1101), a body coat (usually LiquaTile 1184), and a clear coat. (generally EnduraShield 2254).
We have had clients who just use a layer of LiquaTile 1184, in fact there are quite a few floors out there like that. Most of them were before we came on board as the sole Wolverine Coatings distributor for the Do It Yourself market, so I don't have a lot of info on them. I know that if they had troubles that they would eventually call us, and I haven't had any of those calls so I imagine they're holding up fairly well.
Despite that we recommend that all our clients start with a prime coat of BondTite 1101. Before that let me note that the prep work for BondTite, and almost every epoxy out there, is pretty much the same. Some manufacturers have detailed instructions, some just a page or two, but the bottom line is that prep is prep, do it right. Once the prep is done put down a primer, a coating designed to adhere not just mechanically, but also formulated to penetrate the concrete and bond chemically. In the case of BondTite 1101 we spec a 5 mil depth thickness wet. Since it's a 100% solids epoxy there won't be any shrinkage due to water or solvents evaporating, although the final dry thickness might be less due to penetration, which is fine. There doesn't need to be a lot, it's the primer coat, there just need to be enough to dons to the concrete and provide a surface for the body coat to adhere to.
We have had some clients who like to wet look of the BondTite, and just left it at that. Although usually they aim for a final coat of at least 10 mils or more to provide some durability, because although the BondTite sticks like there's no tomorrow (it's even used on steel and other metals) it doesn't provide the same wear and the durability that LiquaTile 1184 does.
It goes on next, we spec 12 mils, and since it's also 100% solids there's no shrinkage, and with the concrete sealed there's no loss there either, so if you apply 12 mils wet, you'll end up with a 12 mil thick layer after it's all cured. As I mentioned LiquaTile can be applied directly to prepped concrete, but it's not really formulated for that - it's an entirely different material. One proof of that is its weight, a 3 quart kit of BondTite weighs about 9 lbs., a 3 quart kit of LiquaTile clocks in at 11 pounds. The big difference is that LiquaTile has ceramic content, that allows it to be hard, but not brittle. As it cures the ceramic content cross-links, so it has an internal lattice, a sort if built in trampoline, which helps it dissipate shock and impact, that helps prevent concrete chip outs, scratches, dings etc.
And that brings us to the clear coat, which I think was your initial concern. On thing to remember is that all epoxies are UV sensitive, they will discolor over time. Wolverine changed the LiquaTile formulation a few months ago, and it's made a big difference in the UV stability, but it will still yellow. On the other hand the polyurethane EnduraShield is UV stable, even if used outdoors in full sunlight. That's one of the main reasons to use a clear coat - UV stability. It's also very clear, so although it filters out most of the UV, a tiny bit will still reach any underlying epoxy, but it greatly decreases the epoxy color shifting.
The clear coat also is harder, it's very hard, so it will resist scratching. It goes on thin, about 3.2 mil when cured, so it doesn't offer a lot of impact mitigation, but that's okay because the underlying LiquaTile takes care of that.
I'd look at the clear coat as a very durable sacrificial coat. In a heavy use environment you may want to to apply another coat of it in a few years after it's seen a lot of use and abuse. But it's done its job, keeping any damage from hitting the LiquaTile layer. So to freshen up the whole floor at that time is a quick and painless process, no grinding or color matching headaches, just lightly sand the clear coat and apply another layer.
If you're on a budget I'd go for a quality primer coat (since that is where almost all epoxy floor failures occur - at that junction where the first layer of epoxy contacts the concrete) and the pigmented epoxy body coat. It will scratch and get marked up easier that a clear coated system, but you'll have a system that won't lift and will protect the concrete. You can still apply the clear coat when budget allows.
If a 2 layer system is still too much, you could go for just the primer coat or just the body coat. I'd opt for the primer coat, especially if the concrete's in pretty good shape. In that case the wet look is a pretty sharp look. If the concrete is nasty looking and has a lot of patches etc., the best technical solution would again be just a quality primer coat, but aesthetically it'd be tough to choose something other than a single coat of high quality pigmented epoxy. One of those form over function calls, but with the right product one that should work out well nonetheless.
Very good info, thank you much. I purchased miracote and pitthane, but no primer, you've convinced me to go get some! I am still a little confused though. If the sealer is well adhered to the concrete, why won't the epoxy bond to that? Doesn't really matter, I'm grinding my **** off to get this sealer off and have $2 a foot in it so far with grinder and materials... What's a little more.
AlphaGarage
Well-known member
I guess a good analogy would be a stain and a paint. A stain is thin and soaks into a lot of places the thicker and more viscous paint won't. But then there are some paints that will adhere better than some stains. These products are lumped into a few classifications, but yet they are vastly different in design and construction. That is even with the same formula they can vary a lot due to the raw materials and manufacturing technique.
Not challenging you at all, but I see it as different than paint and stain. Here's why. If urethane will stick to epoxy as a topcoat, then why won't epoxy stick to urethane as a topcoat? Is it because the urethane is in liquid form when it goes on top?
AlphaGarage
Well-known member
It is different, that was just an analogy. The actual chemical differences are beyond me.
The rule of "urethane on top of an epoxy, but never an epoxy on top of a urethane" is true, but the reasons are likewise beyond me. But your observation is probably correct, the urethane as a liquid is entirely different from the urethane when cured. While it's in it liquid form it bonds with the epoxy, but after it's cured it's an entirely different material.
I'll step out on the ledge yet again (slow learner); water and ice are chemically the same, yet they have entirely different forms and properties. For example, I can easily drive my car on a lake covered with ice, but...
The rule of "urethane on top of an epoxy, but never an epoxy on top of a urethane" is true, but the reasons are likewise beyond me. But your observation is probably correct, the urethane as a liquid is entirely different from the urethane when cured. While it's in it liquid form it bonds with the epoxy, but after it's cured it's an entirely different material.
I'll step out on the ledge yet again (slow learner); water and ice are chemically the same, yet they have entirely different forms and properties. For example, I can easily drive my car on a lake covered with ice, but...
Last edited:
thegarageguy
Well-known member
Epoxies will bond to urethanes, they just have to be sanded and solvent wiped....in some cases re primed.
As to your original question, why top coat? Well, uretanes and polyaspartics afford you more stain resistance, scratch resistance, uv protection and discoloration protection than epoxy alone.
Its not necessary but IMO, will make your floor last much longer.
As to your original question, why top coat? Well, uretanes and polyaspartics afford you more stain resistance, scratch resistance, uv protection and discoloration protection than epoxy alone.
Its not necessary but IMO, will make your floor last much longer.
AlphaGarage
Well-known member
Epoxies will bond to urethanes, they just have to be sanded and solvent wiped....in some cases re primed.
As to your original question, why top coat? Well, uretanes and polyaspartics afford you more stain resistance, scratch resistance, uv protection and discoloration protection than epoxy alone.
Its not necessary but IMO, will make your floor last much longer.
You bring up a good point, that being that with epoxies and coatings in general one must deal with manufacturers for specific info because although many products have the same name they vary greatly.
I should have written "urethane on top of an epoxy, but never an epoxy on top of EnduraShield 2254." We've tried that last combo, various different epoxies on top of scuffed and solvent wiped EnduraShield 2254, in the lab and have had nothing but failures. I guess that's a good thing, you don't want stuff sticking to your clear coat. So we never recommend applying an epoxy over EnduraShield regardless of the epoxy or the preparation.
AlphaGarage
Well-known member
For most cases grinding is the ideal prep, but for a lot of jobs an acid etch will do the trick just fine. I'd say that probably 85% of our DIY projects use a chemical etch, with most of those using muriatic acid.
The chemical, other than muriatic acid, that's frequently used is our OrganiPrep, which isn't caustic as muriatic acid and doesn't have the smell or toxicity.
I should note that the same prep should be used whether you're using a primer or not, in fact the preparation is probably a bit more critical to nail correctly if you are not using a primer. BondTite is a bit more forgiving than a typical pigmented body coat.
There are two thread here at Garage Journal, unfortunately I've lost track of them, but they were from members who used BondTite on their floors.
One related how when he installed his epoxy system he had a set of old floor cabinets, he didn't move them and wasn't able to clean or prep the concrete beneath the cabinets. Months later he go around to replacing the cabinets and while removing the old ones he saw that some of the BondTite 1101 had seeped under the cabinets and was stuck to the totally unprepped concrete.
The other member told of a similar case, but with a floor threshold. A bit of BondTite had leaked under it, adhering to completely uncleaned or prepped concrete.
Both of them thought that it'd be easy to just scrape of the BondTite, after all the are hadn't been even cleaned first, and the BondTite wasn't even back rolled, it just leaked onto the floor. But in both cases they had to chisel off the BondTite, and even then it didn't come off, but rather the concrete broke free first with the BondTite still attached!
We're not say that just because you're using BondTite 1101 primer you can skip prepping the floor, or even take any short cuts, just pointing out that for a long lasting and durable system proper prep - grinding or chemically - and priming is the way to go.
If the floor has previous sealers or coatings, and for some other situations, grinding or shot blasting would be the best option for the pre-prime prep work.
The chemical, other than muriatic acid, that's frequently used is our OrganiPrep, which isn't caustic as muriatic acid and doesn't have the smell or toxicity.
I should note that the same prep should be used whether you're using a primer or not, in fact the preparation is probably a bit more critical to nail correctly if you are not using a primer. BondTite is a bit more forgiving than a typical pigmented body coat.
There are two thread here at Garage Journal, unfortunately I've lost track of them, but they were from members who used BondTite on their floors.
One related how when he installed his epoxy system he had a set of old floor cabinets, he didn't move them and wasn't able to clean or prep the concrete beneath the cabinets. Months later he go around to replacing the cabinets and while removing the old ones he saw that some of the BondTite 1101 had seeped under the cabinets and was stuck to the totally unprepped concrete.
The other member told of a similar case, but with a floor threshold. A bit of BondTite had leaked under it, adhering to completely uncleaned or prepped concrete.
Both of them thought that it'd be easy to just scrape of the BondTite, after all the are hadn't been even cleaned first, and the BondTite wasn't even back rolled, it just leaked onto the floor. But in both cases they had to chisel off the BondTite, and even then it didn't come off, but rather the concrete broke free first with the BondTite still attached!
We're not say that just because you're using BondTite 1101 primer you can skip prepping the floor, or even take any short cuts, just pointing out that for a long lasting and durable system proper prep - grinding or chemically - and priming is the way to go.
If the floor has previous sealers or coatings, and for some other situations, grinding or shot blasting would be the best option for the pre-prime prep work.
Dan Metzler
Active member
- Joined
- Apr 5, 2010
- Messages
- 34
Fred, Your first post is awesome....very informative and straight forward!
So the procedure is an acid wash for the floor prep. Followed by a primer/bonding agent, then the epoxy, and finally a top hard layer to protect against UV and impacts.
How long do you need to wait for a new concrete pour to cure before applying an epoxy floor?
How long do you need to wait for a new concrete pour to cure before applying an epoxy floor?
AlphaGarage
Well-known member
So the procedure is an acid wash for the floor prep. Followed by a primer/bonding agent, then the epoxy, and finally a top hard layer to protect against UV and impacts.
How long do you need to wait for a new concrete pour to cure before applying an epoxy floor?
28 days. Be sure to inform the concrete contractor that you want no sealers applied.