The Importance of Solid Content in Concrete Sealers and Coatings
- Sep 17
- 2 min read
If you’ve ever talked with somebody about concrete sealers or coatings, you’ve probably heard numbers and terms like 70%, 85%, acrylic, polyaspartic, epoxy, polyurethane, 100% solids—and maybe felt a little overwhelmed.
Understanding solid content doesn’t have to be complicated at all. Once you know the basics, it’s an easy concept to grasp.
What Exactly is Solid Content?
Every coating or sealer you buy—whether it’s acrylic, epoxy, polyurethane, or polyaspartic—is sold as a liquid. But not all of that liquid stays behind after application.
Solid Content is the portion of the product that remains on the surface once it cures.
The Carrier (or Carrying Agent) is the part that evaporates, leaving the solid film behind.
For example:
An 85% solids epoxy will leave 85% of the applied material as a durable film, and 15% will evaporate.
A 25% solids acrylic sealer will lose 75% of what you spray to evaporation, leaving only 25% as a protective layer.
The higher the solid content, the thicker and more durable the final coating will generally be.
What Exactly Is The Carrier, and Why Is It Needed?
If some of the product evaporates, why do we need it in the first place? The carrier (the evaporating portion) is what makes the product workable.
It spreads the resins evenly across the surface.
It helps control application rates and drying times.
It makes resins usable, since many are too thick or sticky to apply in pure form.
What Are The Most Common Carriers?
Water – found in water-based sealers; usually has a lower odor and is easier to work with.
Solvents – often stronger in odor, but can provide deeper penetration and higher gloss.
Interesting Fact: Most of the smell from sealers and coatings comes from the carrier, not the solids themselves.
Why Does Solid Content Matter?
The solid content percentage impacts nearly every performance factor of a concrete sealer or coating:
Dry Time – more carrier means longer evaporation and longer cure time.
Film Thickness – higher solids create a thicker, more durable film.
Appearance – affects gloss, sheen, and depth of color.
Workability – determines how easy the product is to apply.
Breathability – coatings with lower solids often allow more vapor transmission.
Knowing these basics helps you choose the right product for your job—whether you need a light acrylic for breathability, a heavy-duty epoxy for durability, or a polyaspartic for fast turnaround.
Key Takeaway:
Solid content isn’t just a confusing number—it’s one of the most important factors in how your sealer or coating will perform. Once you understand the balance between solids and carriers, you can make better choices for your projects, ensuring the right protection, appearance, and longevity for your concrete surfaces.
Stay tuned—we’ll be diving deeper into different carriers, sealers, and coatings in future posts.
