What Is an Epoxy Flake Broadcast Rate?

An epoxy flake broadcast rate is the mass of decorative flakes applied over a measured floor area, usually stated in pounds per 100 square feet or kilograms per square metre. The rate affects the look and flake density, but it is not universal. Flake size, resin system, and broadcast method all matter, so the product specification controls.

A common source of confusion is seeing a number such as “10 lb per 100 sq. ft.” and assuming it guarantees a full, even finish. It does not. That number only describes the amount of flake used for a given area under a particular system and method. It does not, by itself, tell you the correct rate for your floor.

I use the rate as a planning figure, then check the coating manufacturer’s current technical data sheet (TDS) and make a sample area when needed. The TDS sets the system requirements; the sample shows how that flake and resin look together.

What an epoxy flake broadcast rate means

The broadcast rate is the weight of decorative flakes spread over a known floor area. It may be listed as pounds per 100 square feet, pounds per square foot, or kilograms per square metre. It describes flake use, not the coverage rate or thickness of the epoxy resin.

For example, a rate of 10 lb/100 ft² means the plan calls for 10 pounds of flake per 100 square feet. It does not say how much primer, base coat, or clear topcoat to use. Those materials have separate coverage and thickness requirements in the system specification.

Keep the units clear. One pound per 100 square feet equals about 48.8 grams per square metre, or 0.0488 kg/m². That conversion matters because a misplaced decimal can produce a major ordering error.

Broadcast rate versus broadcast-to-refusal

A partial broadcast uses a set amount of flake to create a chosen look. Broadcast-to-refusal means adding flake to wet resin until the surface is no longer visibly exposed. The terms describe different methods, so a rate for one method should not automatically be applied to the other.

With a partial broadcast, the specified weight helps control how much of the base coat remains visible. With refusal, the installer adds flake until wet resin is covered, then recovers loose excess after cure. The amount used can vary with flake size, technique, and the resin layer. Do not infer a refusal quantity from a generic coverage figure.

Key takeaway: Treat a listed rate as a system-specific instruction, not a universal rule for all flake floors.

How to choose a rate and plan flake coverage

The right rate depends on the system, the flake, and the visual result you want. A lower rate may leave more base coat visible; a denser broadcast hides more of it. But flake size and distribution also affect the appearance, so rate alone cannot promise a particular finish.

Start with the product TDS or written system specification. Check whether it calls for a measured partial broadcast or broadcast-to-refusal, and confirm which flake size and type the system allows. If the documents do not state a rate, ask the manufacturer or supplier for written direction rather than treating a retailer’s general estimate as a requirement.

A small test area can help you judge the appearance and the installer’s distribution method. It does not replace the TDS or prove that the floor is ready for coating. If you compare samples, use the same base coat, flake, broadcast method, and topcoat planned for the job.

Do not confuse flake rate with coating coverage

Resin coverage is commonly expressed as an area per unit of product, while flake broadcast rate is a mass per unit of area. They answer different questions. Use the resin TDS to calculate base coat and topcoat quantities, and use the flake specification to estimate decorative flake.

Key takeaway: Choose the method and appearance first, then confirm a compatible rate in the system documents.

How to calculate the flake quantity

To estimate flake needed for a partial broadcast, multiply the floor area by the specified rate. Keep the units consistent. If the rate is given per 100 square feet, divide the area by 100 before multiplying by that rate.

Flake quantity (lb) = floor area (ft²) × rate (lb/ft²)

For example, 500 square feet at a specified rate of 0.10 lb/ft² requires 50 pounds of flake before any allowance for waste or recovery. This is a calculation example, not a recommended rate. The project’s specified rate must come from its coating system.

The rates in the table show the math only. They are not coverage recommendations. For a partial broadcast, ask the system supplier how much extra to allow for handling, edges, and cleanup. For refusal, do not use the table to predict consumption; the method is based on fully covering wet resin, and loose excess is recovered after cure.

Key takeaway: Write down the area, rate, units, and broadcast method before ordering. That makes the estimate easy to check.

Substrate inspection, concrete preparation, and moisture testing

A broadcast rate cannot make an unsuitable floor ready for coating. Most epoxy flake systems are designed for sound, properly prepared concrete. The coating manufacturer must approve the substrate and preparation method; do not assume a product approved for concrete is suitable for wood framing or another floor assembly.

Check the slab for weak or loose material, cracks, oil, old coatings, and other contamination. Prepare concrete mechanically to the surface profile required by the TDS. Some thin-film systems call for about ICRI CSP 2–3, but that is not a universal target. The specified profile controls. Remove dust and debris before coating.

Moisture needs a test, not a visual guess. A dry-looking surface does not prove that moisture movement is acceptable. Use the method required by the coating manufacturer, commonly ASTM F2170 for in-situ relative humidity or ASTM F1869 for moisture vapor emission rate (MVER). There is no single moisture limit that suits every epoxy system. Follow the product limit, and use only a compatible mitigation system if results exceed it.

Excess moisture beneath a low-permeability coating can contribute to blistering or loss of adhesion. If the slab fails the product’s limit, do not coat it until the manufacturer-approved corrective plan is clear.

Key takeaway: Confirm substrate approval, surface profile, and moisture acceptance before calculating application quantities.

Applying the base coat and broadcasting flakes

Broadcast flakes into the specified wet base coat, while it remains within the product’s application and recoat window. The base coat’s coverage and thickness come from its TDS, not from the flake rate. Keep a steady wet edge so the coating does not cure before the next section is joined.

A reliable sequence is:

• Inspect the substrate, test moisture, and repair defects with compatible materials.
• Mechanically prepare concrete to the specified profile, then vacuum it thoroughly.
• Apply the approved primer or base coat at the stated coverage and thickness.
• Broadcast flakes evenly at the specified rate, or to refusal if the system calls for that method.
• Let the coat cure as directed. Scrape or abrade sharp, high flakes if the system requires it, then vacuum loose material.
• Apply the specified clear topcoat or coats at the stated coverage and thickness.

Watch temperature and humidity during application and cure. Follow the TDS limits, and keep the slab at least 5°F (3°C) above the dew point unless the system specifies otherwise. If resin has skinned over or passed its recoat window, do not broadcast onto it without an approved corrective procedure.

Key takeaway: Timing matters. Use the flake method while the resin is in its approved working window.

Installation examples: using the rate in real planning

These examples show how rate and method change the quantity calculation. They are planning scenarios, not reports of completed jobs, and they do not establish a recommended rate. In both cases, the selected system’s current written instructions take priority.

Example 1: Measured partial broadcast

A homeowner has a 500-square-foot concrete floor and a written system specification calling for 0.10 lb/ft². The math is 500 × 0.10, or 50 pounds. The homeowner should then confirm any waste allowance with the supplier and use a test area to check the intended appearance.

If the flake size or broadcast technique changes, the same weight may not look the same. The homeowner should not raise or lower the rate based only on a general online estimate.

Example 2: Broadcast-to-refusal

A tradesperson coats a 300-square-foot area using a system that calls for refusal. Here, multiplying by a generic rate would not establish the quantity. The installer broadcasts flake until wet resin is no longer visibly exposed, allows the coat to cure as directed, and recovers loose excess.

In either scenario, the area must be measured accurately, and the resin must be applied at its specified rate. A change in floor area or coating method changes the work plan.

Key takeaway: Use arithmetic for a specified partial rate; use the system’s refusal procedure for a refusal broadcast.

Topcoat, edges, and floor movement

The clear topcoat protects and locks in the flake, but it does not correct poor preparation or an unsuitable broadcast. Apply the specified topcoat at its stated rate and thickness. Follow its recoat window and cure instructions, and confirm whether the system requires more than one coat.

Plan edges, thresholds, drains, and transitions as part of the coating system. Respect existing movement joints and use the manufacturer’s detail for cracks or transitions. Do not bridge a joint or assume that a decorative flake layer will prevent substrate movement from affecting the coating.

If the substrate is wood, get approval for the entire floor assembly, including its stiffness and any required overlay. A concrete coating approval does not automatically approve wood. Tile deflection guidance, such as L/360, is not a substitute for the epoxy manufacturer’s substrate requirements.

Key takeaway: A durable finish depends on the full approved system, including edges, joints, and topcoat.

Conclusion and frequently asked questions

The broadcast rate tells you how much flake to apply over a measured area, but the number only makes sense alongside the flake size, resin system, and broadcast method. Confirm the current TDS, calculate quantities with consistent units, and prepare and test the substrate before coating. A sample area can help check appearance, but it does not replace system requirements.

What does lb/100 ft² mean?
It means pounds of flake used for each 100 square feet of floor.

Is there one standard epoxy flake broadcast rate?
No. The rate depends on the coating system, flake, and method. Follow the current TDS.

Does a higher rate always mean a better floor?
No. It generally means more flake is applied, but the correct amount depends on the specified look and system.

How do I calculate flakes for a partial broadcast?
Multiply the floor area by the specified rate in pounds per square foot. Keep units consistent.

Can I use a partial-broadcast rate for refusal?
No. Refusal means covering exposed wet resin with flake. It cannot be reliably estimated from an unrelated partial rate.

How much flake does 500 square feet need at 0.10 lb/ft²?
The calculation is 500 × 0.10, which equals 50 pounds before any waste or recovery allowance.

Does flake size affect the broadcast rate?
It can affect how a given weight looks and spreads. Use the flake size approved for the system.

Can I broadcast onto cured or tacky resin?
Only if the system’s written procedure allows it. Do not broadcast onto resin that has skinned over or passed its recoat window without approved direction.

How should I check concrete moisture?
Use the test method and acceptance limit required by the coating manufacturer, commonly ASTM F2170 or ASTM F1869.

Can a concrete epoxy system go over wood?
Not automatically. The manufacturer must approve the full wood assembly and its preparation.

(This article was written by one of our staff writers, Marcus Vance. Visit our Meet the Team page.)