“100% solids,” “water-based,” and “solvent-based” describe formulation and film-formation features—not a universal quality ranking. Each category contains products with different resin/hardener chemistry, volume solids, viscosity, thickness limits, cure schedules, moisture requirements, VOC values, hazards, and system roles.

Short answer: 100%-solids epoxy can retain nearly all applied volume as film and support high build where its TDS permits. Water-based epoxy uses water as part of the carrier and commonly leaves a thinner dry film than its wet application. Solvent-based epoxy uses organic solvent carrier and also loses volatile volume. None of those facts alone establishes adhesion, strength, safety, or project suitability.

This is a technical, research-based comparison. Named products are documented examples—not universal representatives, rankings, or evidence of hands-on testing.

Start with solids by volume

Volume solids is the percentage of a mixed coating’s liquid volume expected to remain in the dry film under the product’s stated test method. It connects wet-film thickness (WFT) and dry-film thickness (DFT):

DFT ≈ WFT × volume-solids fraction

A 50%-volume-solids product applied at a hypothetical 10 mils WFT would have a theoretical 5 mil DFT. That is calculation, not a permission to apply that product at 10 mils. The TDS must allow the wet and dry build.

For a product documented as 100% solids by volume, the simple theoretical relationship makes WFT and DFT approximately equal. Real installed film can still vary because of profile, porosity, surface geometry, transfer loss, entrained air, measurement, and application control.

Read the floor thickness and coverage guide before comparing package coverage.

Category comparison

Attribute 100%-solids epoxy Water-based epoxy Solvent-based epoxy
Carrier/volatile phase Designed with essentially no volatile carrier by the named solids definition Water is a principal carrier, with formulation-specific co-solvents/additives possible Organic solvent is a carrier; exact solvents and amount vary
WFT-to-DFT change Theoretical dry film remains close to wet film when 100% volume solids is documented Dry film is materially thinner than wet film according to volume solids Dry film is materially thinner than wet film according to volume solids
Typical system role High-build coat, binder, broadcast receiver/sealer, primer, mortar, or specialty lining depending on product Thin coating, primer/base, breathable system component, or finish depending on product Penetrating/coating roles and specific industrial floor uses depending on product
Application behavior Can be viscous or exotherm/working-time sensitive; product design varies Water release, humidity, ventilation, freeze protection, and substrate conditions can matter Solvent release, ventilation, flammability, and recoat conditions can matter
VOC/odor May publish low or zero regulatory VOC, but that does not establish toxicity or odor May publish low VOC/odor, but water-based does not mean solvent-free or harmless Often has higher VOC content, but exact value and exempt compounds require the TDS/SDS
Best use Only when the exact product/system fits build, substrate, exposure, and schedule Only when the exact product/system fits film, cure, moisture, and service Only when the exact product/system and site controls fit the task

The word “typical” must not replace a product document. Some water-based epoxy systems are described as breathable; that does not make every water-based coating moisture-mitigating. Some 100%-solids products are high build; that does not authorize unlimited thickness.

100% solids: what the term means

“100% solids” should be verified as by volume, by weight, or “as supplied.” Those are not automatically the same specification. Pigment packs, reducers, aggregate, and field additions can also change the mixed material.

Sika’s Sikafloor-225 N TDS describes a low-odor, 100%-solids epoxy intended for high-build and decorative quartz/flake applications. It also identifies named system roles and the possibility of an aliphatic urethane topcoat. That demonstrates a documented high-solids floor product, not every possible use of 100%-solids epoxy.

Advantages that may be available

  • higher dry film from a given permitted wet film;
  • reduced loss of carrier volume during cure;
  • high-build, broadcast, slurry, or mortar roles where documented;
  • low regulatory VOC values in some formulations;
  • fewer coats for a target build when the complete system permits it.

Limitations to verify

  • viscosity and ability to wet the specified profile;
  • working time, exotherm, mixed mass, and immediate placement;
  • maximum and minimum film thickness;
  • outgassing and pinhole response on porous concrete;
  • temperature and dew-point limits;
  • UV/color stability and required topcoat;
  • exact moisture acceptance;
  • component SDS hazards and PPE.

“100% solids” does not mean non-toxic, food safe, odorless, nonflammable, moisture proof, or acceptable without ventilation. Those are separate claims.

Water-based epoxy: water is not a safety certification

Water-based or waterborne epoxy uses water in the formulation/carrier system. As water and any other volatile components leave, the remaining film is governed by the product’s volume solids.

Sherwin-Williams’ April 2024 Resuflor WB PDS is a documented example from its EMEAI portfolio. It describes a two-component water-based polyamine epoxy and publishes 41% ± 2% mixed volume solids, with product-specific WFT/DFT recommendations and environmental conditions. That number applies to that regional product/document, not to all water-based epoxy.

Advantages that may be available

  • lower product-specific VOC content than a comparable solventborne option;
  • water cleanup while uncured when the manufacturer permits it;
  • thinner coating or breathable-system roles;
  • application in occupied-project strategies when the complete emissions, odor, ventilation, and cure requirements fit.

Limitations to verify

  • minimum/maximum application and substrate temperature;
  • humidity, ventilation, and water-release conditions;
  • freeze protection and storage;
  • thinner DFT at a given WFT;
  • number of coats and hiding/color uniformity;
  • chemical, abrasion, and water-service limitations;
  • moisture tolerance versus true mitigation;
  • current SDS for resin, hardener, additives, and cleaners.

Water-based does not mean the uncured components can be handled without skin/eye protection or exposure controls. It also does not prove zero VOC: co-solvents and other volatile compounds may be present.

Solvent-based epoxy: formulation-specific, not automatically stronger

Solventborne epoxy uses one or more organic solvents to adjust application properties and film formation. The exact carrier, solids, VOC, flammability, exposure controls, permitted thickness, and cure behavior belong to the named product.

Sherwin-Williams describes ArmorSeal 1000 HS as a two-component, high-solids polyamide epoxy using solvent-liquid-coating technology. Its public page lists a representative VOC value below 340 g/L and directs users to exact part-specific data sheets. That is a product example, not a category performance benchmark.

Advantages that may be available

  • product-specific wetting, flow, or penetration behavior;
  • an established industrial system role;
  • thinner-film application where the selected specification calls for it;
  • a particular recoat or service profile documented by the manufacturer.

Limitations to verify

  • exact solvents and SDS hazards;
  • ventilation and occupational exposure controls;
  • fire/ignition and storage requirements;
  • regulatory VOC restrictions by jurisdiction and use;
  • permitted WFT/DFT and solvent entrapment risk;
  • recoat timing and full cure;
  • compatibility with occupied-space schedules.

Solvent-based does not mean universally stronger, more chemical resistant, or more durable. Those require product- and test-specific evidence.

VOC, odor, exposure, and toxicity are different

EPA explains that VOC terminology can refer to different outdoor regulatory and indoor-air contexts. Its current technical overview warns that compounds excluded from an outdoor regulatory VOC definition may still matter indoors. EPA also states that a low- or no-VOC label does not by itself establish a safer product because the individual compounds and emissions differ.

Therefore:

  • low odor does not prove low VOC;
  • low VOC does not prove low emission of every relevant chemical;
  • zero regulatory VOC does not prove non-toxic;
  • water-based does not prove harmless;
  • 100% solids does not prove no inhalation or skin hazard;
  • a respirator decision cannot be made from formulation category alone.

NIOSH advises preventing skin contact with uncured epoxy/resin components and using exact product information to select controls. It also recommends engineering controls, PPE, and worker education for organic-solvent exposure. Begin with the current SDS for Part A, Part B, pigments, reducers, cleaners, and any other component, then apply task-specific occupational guidance.

Application behavior and cure

Formulation affects placement, but category slogans are unreliable.

Working time

A high-solids coating can concentrate reactive material in the mixed pail; mass and temperature may shorten usable time. A water-based product can have a long pot life but still require controlled drying conditions. A solventborne product can remain wet while solvent releases, but that does not make its recoat schedule flexible.

Compare exact pot life, working time, induction time, batch size, material temperature, and placement instructions.

Film formation

Reactive cure and carrier loss can occur together. Do not treat “dry to touch” as full cure or recoat permission. Applying a waterborne or solventborne product too thickly can interfere with release; applying a 100%-solids product too thickly can create other cure, heat, leveling, or defect risks.

Use the exact cure and recoat schedule.

Shrinkage

Lower volume solids means more initial wet volume is expected to leave before the theoretical dry film remains. That is film-volume change, not proof of cracking, delamination, or dimensional failure. Those outcomes depend on product, thickness, substrate, cure, stress, and system design.

Substrate wetting and primer selection

A low-viscosity product may wet a prepared surface effectively, but neither solids category nor carrier alone proves penetration or adhesion. Profile, porosity, surface energy, contamination, temperature, application rate, and cure matter.

Use the technical primer guide to decide the required role and the primer comparison to choose among documented system products. Do not dilute or reduce a coating unless the current TDS expressly permits the exact material and amount.

Selection framework

Choose a formulation only after answering:

  1. What layer is this—primer, build coat, broadcast receiver, grout, or topcoat?
  2. What WFT/DFT and volume solids does the current TDS specify?
  3. Does the product accept the verified concrete moisture, profile, temperature, and exposure?
  4. Can carrier release or reactive cure occur under actual ventilation and humidity conditions?
  5. Do the product’s working and recoat windows fit the crew and floor size?
  6. Does its documented chemical, UV, abrasion, and service performance fit the project?
  7. Are all neighboring layers manufacturer-approved?
  8. What controls and PPE do the current component SDS documents require?

For a garage, use these answers inside the complete system selector. A formulation category is one input, not the final system.

Commercial comparison rules

A useful future product module can compare documented layer role, solids by volume, permitted film, coverage, mix, working/recoat schedule, moisture limit, temperature range, finish compatibility, SDS access, and package size.

It should not rank by solids percentage alone or claim that the “strongest” formulation wins. There are no affiliate product links on this page at publication; see the affiliate disclosure.

Return to the epoxy flooring hub for the substrate-to-service decision sequence.

Future visual opportunity

A future film diagram could show equal WFT bars drying to different theoretical DFT values at user-selected volume solids. It should explain volume loss without implying that one resulting film is automatically better.

Sources and technical references

Accessed September 2026. Product documents can change; verify the current revision before specifying or installing a system.

  1. Sikafloor-225 N Product Data Sheet — Sika USA
  2. Resuflor WB Product Data Sheet, April 2024 — Sherwin-Williams Protective & Marine
  3. ArmorSeal 1000 HS product information and datasheets — Sherwin-Williams Protective & Marine
  4. Technical Overview of Volatile Organic Compounds — US Environmental Protection Agency
  5. Does EPA regulate VOCs in household products? — US Environmental Protection Agency
  6. About epoxies and resins and reproductive health — CDC / NIOSH
  7. Organic Solvent Neurotoxicity — CDC / NIOSH