Epoxy Flooring for Corn Silage and Dairy Areas

The Important Question Is Not Just “What Is the pH?”

When we select an epoxy coating for chemical service, pH is useful background information, but it is not the deciding factor. The coating is exposed to a specific reagent, at a specific concentration, for a specific length of time and at a particular temperature.

Two liquids can have a similar pH and affect the same cured epoxy very differently. For a corn-silage or dairy floor, the useful questions are:

Which organic acids and fermentation products are present?
Approximately how concentrated are they?
Will the residue remain wet, dry in place, or be repeatedly rewetted?
Will urine, milk, manure, detergents, sanitizers or caustic cleaners also contact the floor?
How long will each material remain before cleanup?

What Corn Silage Produces

During successful ensiling, microorganisms convert plant sugars primarily into lactic acid, with acetic acid normally the second major fermentation acid. Smaller amounts of propionic acid, ethanol and other fermentation products may also be present.

Once silage is exposed to air during feed-out, additional aerobic spoilage and decomposition can occur. Poor or secondary fermentation may also introduce butyric acid, ammonia, amines and other decomposition products. The actual mixture varies with crop moisture, storage, temperature, oxygen exposure, inoculation, age and housekeeping.

Typical corn-silage fermentation products and approximate as-fed scale
Fermentation product	Typical level reported on dry-matter basis	Approximate as-fed level at 30–40% dry matter	Flooring significance
Lactic acid	About 3–6% of dry matter	About 0.9–2.4% of the total wet silage	Primary acid of concern in normal well-fermented corn silage.
Acetic acid	About 1–3% of dry matter	About 0.3–1.2% of the total wet silage	Second major organic acid; more volatile than lactic acid.
Propionic acid	Often around 0.1% DM or less in ordinary corn silage	Usually only a few hundredths of a percent as-fed	Normally a minor constituent, but still part of the chemical mixture.
Ethanol	Often about 1–3% of dry matter	About 0.3–1.2% as-fed	Fermentation byproduct that should also be considered in coating selection.
Butyric acid / ammonia	Normally low in good corn silage; elevated levels indicate undesirable fermentation	Highly variable	More likely where material has fermented poorly or is undergoing secondary decomposition.

These are composition estimates, not an analysis of liquid collected from a floor. The “as-fed” figures are simple estimates obtained by multiplying the dry-matter acid percentage by a 30–40% dry-matter content. Leachate or residue on a particular floor can be more or less concentrated.

What Happens to the Lactic Acid as the Residue Dries?

This is one of the most important points in evaluating the floor. Water can evaporate while much of the lactic acid remains. Lactic acid is far less volatile under ordinary floor-drying conditions than the water carrying it. Therefore, as a wet silage residue loses water, the remaining liquid phase can become progressively richer in lactic acid and other nonvolatile dissolved material.

Simple illustration: if a liquid initially contained 1% lactic acid and lost enough water that only one-fifth of the original liquid remained, the remaining liquid could theoretically approach about 5% lactic acid if none of the acid had reacted, biodegraded or otherwise been removed.

Real silage residue is more complicated than that calculation. Some acids can volatilize, microorganisms continue to act on the material, and acids can react with the substrate. Acetic acid, for example, is considerably more volatile than lactic acid and may be lost to the air to a greater extent during drying.

On unprotected Portland-cement concrete, lactic and other organic acids also react with calcium-bearing compounds in the cement paste. That means some acid is consumed while the concrete itself is being chemically attacked. The surface can progressively soften, become more porous, lose cement paste and eventually expose aggregate.

On a chemically resistant coating, residue can remain at the surface. If it is later hit with wash water, urine, fresh silage liquid or condensation, soluble residue can be redissolved. The coating may therefore see repeated:

wetting → concentration during drying → residue → rewetting

That repeated cycle is one reason it is prudent to select a coating with chemical resistance comfortably beyond the nominal acid concentration in fresh silage.

Why Product #633 Is a Logical Choice for This Exposure

In many feed or milking areas, the mechanical traffic may be relatively light—often little more than people walking in rubber boots. In that situation, the reason to move to a novolac system is not necessarily abrasion. It is the chemical environment.

Epoxy.com Product #633 is a chemical-resistant novolac epoxy coating. The published Epoxy.com Chemical Resistance Chart includes several reagents that are directly relevant to silage and dairy areas.

Of particular interest, #633 is listed for continuous service at 50% lactic acid. That is far above the approximate lactic-acid content normally associated with fresh corn silage, and it provides useful margin for concentration during drying and repeated exposure.

Important: A high test concentration does not mean every real-world silage application is automatically suitable. Chemical resistance also depends on temperature, exposure duration, mixtures, film thickness, substrate condition, cure, cleaning practices and whether the service is splash-and-spill or true immersion.

The Existing Concrete Still Matters

Concrete that has already been exposed to silage acids for years may have a weakened or chemically altered surface layer. A coating cannot restore strength simply by being applied over soft concrete.

Before coating, deteriorated material, contamination and unsound cement paste should be removed by appropriate mechanical preparation until sound concrete is reached. The condition of the existing substrate can be more important to long-term adhesion than adding unnecessary coating thickness.

Slip Resistance Without Making the Floor Impossible to Clean

Dairy and feed floors are frequently wet. Even when the only traffic is rubber-boot foot traffic, some surface texture is normally desirable.

There is a balance. Too little texture can create a slippery floor. Too much texture traps silage, manure and other organic material and makes routine washing harder. The goal is enough anti-skid texture for secure footing while preserving practical cleanability.

Other Dairy-Area Chemicals Should Be Identified

Corn silage is only one part of the service environment. Before final system selection, identify the cleaners and sanitizers actually used in the area. Depending on the operation, the floor may also see urine, manure, milk residue, detergents, sodium hypochlorite, sodium hydroxide or other cleaning compounds.

The correct way to specify chemical-resistant epoxy is to compare the actual chemicals, concentrations, temperature and cleanup interval with published resistance data—and to test under actual or simulated conditions when the exposure is unusual or critical.

The Bottom Line

Corn silage should not be treated simply as “something with a low pH.” It is a changing chemical mixture dominated by lactic and acetic acids, with other fermentation and decomposition products present in smaller amounts.

Fresh silage normally contains relatively dilute organic acids when viewed on an as-fed basis, but a residue left on the floor can change as water evaporates. Lactic acid in particular can remain while water is lost, creating a more concentrated residue that may later be rewetted.

For epoxy selection, the better question is not:

“What is the pH?”

It is:

“What reagent is present, at what concentration, at what temperature, and for how long?”

That is the technical basis for considering a chemical-resistant novolac epoxy such as Epoxy.com Product #633 in corn-silage and dairy-flooring environments.

Selected #633 Chemical-Resistance Ratings Relevant to Silage and Dairy Areas

The following is a small selection from the Epoxy.com Chemical Resistance Chart. Always review the full chart and the actual service conditions before final selection.

Product #633 — selected published ratings
Reagent	Published concentration	#633 rating	Why it may matter here
Lactic Acid	50%	+	Primary acid produced in normal corn-silage fermentation.
Acetic Acid	56%	S-2	Second major silage acid; this test concentration is far above normal as-fed silage levels.
Vinegar	Published as vinegar	+	Useful practical reference for dilute acetic-acid exposure.
Ethanol	Published without concentration	+	Common silage fermentation byproduct.
Urine	Published without concentration	+	Common secondary exposure in cattle and dairy areas.
Sodium Hypochlorite	10%	+	Representative of a possible chlorine-based cleaning or sanitizing exposure.
Sodium Hydroxide	50%	+	Relevant where strong alkaline/caustic cleaning products are used.

Rating key: + = Continuous Service (greater than 6 months). S-2 = Splash and Spill with 24-hour Cleanup. Ratings shown above are reproduced from the Epoxy.com Chemical Resistance Chart. Temperature, mixtures, immersion, cleanup practices and other service conditions can change suitability.

Technical Sources and Further Reading

Pennsylvania State University Extension, “What’s in Your New Crop Corn Silage?” — fermentation products and typical corn-silage acid ranges.
Pennsylvania State University Extension, “Corn Silage Production and Management” — fermentation profiles across different dry-matter ranges.
Epoxy.com, Epoxy Chemical Resistance Chart — published comparative chemical-resistance ratings.
Epoxy.com, Product #633 Chemical-Resistant Novolac Epoxy Coating — product information and chemical-service guidance.
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