Published August 17, 2026 · Updated August 23, 2026 · By Tupep
Broadcast flake is the cheapest looking upgrade on an epoxy floor and the most commonly underestimated one. Not because flake is expensive, but because of what it does to the clear coat that goes over it. A full flake floor can eat nearly twice the top coat of the same floor with no flake at all, and the reason is geometry, not absorption.
What “broadcast to rejection” actually means
You seed color flake into the wet base coat. A light broadcast means you throw a controlled amount and let base color show between chips. Broadcast to rejection means you keep throwing until the surface will not accept another chip and the excess bounces off. Once cured, you scrape and sweep off the loose flake, and what’s left is a surface of chips standing at every angle, most of them partly on edge.
That surface feels like coarse sandpaper. It’s essentially a field of tiny vertical walls. Roll a clear coat on it and the resin has to fill every valley before it can level, and the true wetted area is well above the floor’s plan area. Both effects push consumption up.
Where the base number comes from
One gallon of 100 percent solids resin covers 1,604 square feet at one mil of dry film thickness. That’s a gallon, 231 cubic inches, spread 0.001 inch thick: 231,000 square inches, divided by 144 square inches per square foot, is 1,604. Every figure below starts there and then gets corrected for what the flake did to the surface.
The formula
Flake weight (lb) = Area x broadcast rate in lb/sq ft
Clear coat gallons = (Area x target DFT in mils) / 1,604 / volume solids fraction x flake factor
The flake factor accounts for the fill demand and the added surface. It is a planning number, not a physical constant, and it climbs with both broadcast density and chip size.
Broadcast rate, flake factor, and coverage
| Broadcast level | Rate (lb/sq ft) | Flake factor | Clear coverage at 10 mils |
|---|---|---|---|
| No flake | 0 | 1.0 | 160 sq ft/gal |
| Light, 10 to 25 percent | 0.05 to 0.10 | 1.15 | 139 sq ft/gal |
| Medium, 50 to 75 percent | 0.15 to 0.25 | 1.35 | 119 sq ft/gal |
| Full rejection, 1/8 in chip | 0.30 to 0.40 | 1.6 | 100 sq ft/gal |
| Full rejection, 1/4 in chip | 0.40 to 0.50 | 1.8 | 89 sq ft/gal |
The coverage column is 1,604 divided by 10 mils, which is 160.4 sq ft/gal, then divided by the flake factor. Bigger chips stand taller and leave deeper valleys, so a quarter inch flake floor needs more clear than an eighth inch floor at the same broadcast density.
Worked example: 400 square foot garage, full flake, 1/4 in chip
Flake. 400 x 0.45 lb/sq ft = 180 lb. You will sweep up a lot of that. Reclaim on a clean floor typically runs 30 to 50 percent, but you have to have it on hand to throw it, so buy for the broadcast, not for the net. Order 180 lb and expect to keep 60 to 90 lb.
Grout coat. This is the first clear, the one that fills. 100 percent solids clear at a 10 mil target. 400 x 10 = 4,000, divided by 1,604 is 2.49 gallons. Multiply by the 1.8 flake factor and you get 4.48 gallons. That works out to about 89 sq ft per gallon, which is roughly half what the same clear would cover on a flat floor.
Second clear. The surface is mostly filled now, so the factor drops. Take a 90 percent solids polyaspartic at 4 mils. 400 x 4 = 1,600, divided by 1,604 is 1.00 gallon of film. Divide by 0.90 for solids and you get 1.11 gallons. Multiply by a 1.15 factor for the residual texture and you’re at 1.28 gallons.
Total clear: 4.48 + 1.28 = 5.76 gallons, before waste. Add 10 percent and buy 6.5 gallons. On the same floor with no flake, two coats would have run under 4. We have watched people buy the no-flake quantity for a full flake floor and end up with a starved, gritty finish they had to recoat.
Why full flake changes the finish, not just the volume
- Texture is permanent below a certain thickness. A thin clear coat over full flake stays rough. If you want a smooth floor, you need enough grout coat to bury the chips, and often a light sand between clears to knock down the high points.
- Slip resistance comes free, or gets removed. Full flake with a thin clear is naturally grippy. Bury it in a thick, glossy clear and you have a slick floor, which is why many installers add an anti-slip additive to the final coat rather than relying on the chips.
- Prep between coats is real work. Scraping and sweeping a rejection-broadcast floor takes longer than the broadcast did.
Timing, temperature, and safety
Broadcast has to happen into wet base, which means the base coat’s pot life sets the pace of the whole job. Pot life roughly halves for every 18 degrees F of temperature rise, so a base that gives 40 minutes at 65 degrees may give 20 at 85. On a hot day, we cut the base into smaller sections and keep one person mixing and rolling while another throws flake, because a section that skins over before it’s seeded is a section that has to be ground back.
Throw flake upward and let it fall flat rather than firing it at the floor. Chips that land on edge and stick that way are exactly what drives the top coat number up.
On safety: ventilate the bay, move air out rather than just stirring it around, and wear chemical resistant gloves and eye protection. Broadcasting flake also puts light plastic dust in the air, so wear a dust mask during the throw and the sweep. Rates, solids, and recoat windows vary by product, so confirm everything against the technical data sheet before you order.
Related guides
- How Much Epoxy for a 2-Car Garage Floor
- Epoxy Primer on Bare Concrete: The Porosity Test
- Epoxy for a Countertop Flood Coat
- Concrete for a 4×8 Patio
Sources and Further Reading
Run your own numbers with the Epoxy Calculator, or browse every tool on the calculators index. Coverage figures and material constants are cross-checked against manufacturer technical data sheets before publication. See our Methodology page for how figures are selected and verified.
Planning estimate only. Results assume standard conditions and are intended for material planning. Verify against your product’s technical data sheet and your local building code before purchasing. Structural, electrical, and gas work should be specified by a licensed professional.
Last updated: August 23, 2026
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