Single vs Double Quartz Broadcast: How Much Aggregate You Need
What separates the two systems, and why "broadcast to refusal" is an end point on the floor with a planning rate behind it.
Last updated October 22, 2026
Single broadcast is one epoxy coat, quartz broadcast to refusal, then a clear topcoat, which is the usual choice for residential and light commercial floors. Double broadcast repeats the whole cycle twice for extra film build, typically for high-traffic commercial or outdoor areas. Either way, “broadcast to refusal” is an end point you see on the floor, and the ordering figure is a planning rate behind it. A common manufacturer figure is 0.5 lb/ft² (2.44 kg/m²) per coat.
What “broadcast to refusal” actually means
Refusal is a physical end point, not a measured quantity. You keep throwing quartz into the wet resin until the surface stops taking any more and fresh aggregate simply sits dry on top of what is already there. At that point the coat is saturated: there is no wet resin left showing anywhere, and the floor looks uniformly like quartz rather than like resin with quartz in it.
The 0.5 lb/ft² figure is what refusal costs you in material on a typical floor. It is a planning number for ordering, not a target to meter out on site. You do not stop broadcasting because you have used your half pound; you stop because the floor refused it. If your floor takes noticeably more or less, that is real information about your substrate and profile, and the calculator lets you replace the rate with your own figure.
Under-broadcasting shows as shiny or wet-looking, resin-rich patches. Caught while the coat is still wet, the fix is to broadcast more into them. If the topcoat goes on over them, the only fix is another coat, which is why the order has to cover a full saturation.
Single or double, and how to decide
Double broadcast is not a heavier single broadcast. It is the whole cycle run twice: base coat, broadcast to refusal, cure, sweep back the excess, then a second resin coat and a second full broadcast. That is why it doubles the quartz exactly, and why it takes more labor and time: a second resin coat, a second broadcast and another cure.
Single broadcast suits
- Residential garages, basements, laundries
- Light commercial: retail floors, offices, showrooms
- Interior floors with predictable, mostly foot traffic
Double broadcast suits
- Commercial kitchens and food service
- Pool surrounds and outdoor areas
- Warehouse floors that need extra build
What you actually gain
- More film build, so more to wear through before the substrate is exposed
- A second coat can cover minor flaws in the first
What it costs you
- Exactly double the quartz, which the calculator shows directly
- A second full resin coat on top of that
- An extra cure window, which can add a day on site
How to read the inputs
Floor Area
- The total area getting the quartz broadcast, in ft² or m²
Broadcast Coats
- Single (one epoxy coat, one broadcast) or double (two full coats, each broadcast to refusal). Double simply doubles the quartz needed
Broadcast Rate & Waste
- Defaults to the 0.5 lb/ft² full-saturation rate, editable to match your product’s TDS, plus a waste allowance for overspray and edges
Bags to Order
- Defaults to a 50 lb bag with common presets, always rounded up to a whole bag
Worked example
A 1,000 ft² floor, single broadcast, at the default 0.5 lb/ft² rate: net quartz = 1,000 × 0.5 = 500 lb. With a 10% waste allowance: 500 × 1.1 = 550 lb total, exactly 11 bags at 50 lb each. Switching to double broadcast would double the net figure to 1,000 lb before waste.
Ordering without double counting
Three separate things pad a quartz order, and it is easy to apply all three without noticing. The waste allowance is the first, and it is already inside the total the calculator reports. Rounding to whole bags is the second, and it happens automatically. A third manual overage on top of those is where contractors end up with an unopened pallet in the corner of the workshop.
Take the worked example above. Net quartz is 500 lb. The default 10% waste allowance takes it to 550 lb, and 550 divides exactly into 11 bags with nothing left over, which is unusually tidy. On an 800 ft² floor it is less tidy: 400 lb net becomes 440 lb with waste, and 440 lb needs 9 bags, so you buy 450 lb. The round-up alone added another 10 lb you did not ask for.
If your site genuinely needs more headroom, raise the waste percentage rather than adding a second allowance by hand. That keeps one number doing the job, and it keeps the figure the tool reports the same as the figure you actually order against.
Try it with your own floor
Enter your floor area and choose single or double broadcast. The rate and bag size are both editable.
Full result gives total quartz, net quantity, and bags to order.
Open the live calculator →When your floor will not match the rate
The default rate is a broadcast-grade quartz figure taken to refusal on a prepared slab. Several ordinary things move it, and none of them mean the number is wrong:
Surface profile
- A more aggressive grind leaves more texture to fill
- An open, porous slab takes more resin, which can mean a heavier first coat
Aggregate size
- Mesh size mainly changes texture and slip resistance
- A genuinely different grade can change the rate, so use your own product sheet
Technique and conditions
- Throwing high and letting quartz fall flat wastes less than throwing across the floor
- Wind on an outdoor pour adds to the loss
Edges and cut-ins
- A small floor with many edges loses proportionally more than a big open bay
- This is what the waste allowance is for, so raise it rather than the rate
Whatever you settle on, put it in the rate field and leave it there. The calculator remembers it, so your own measured figure becomes the default for every future job instead of a number you rederive each time. If quartz is one line in a bigger quote, the epoxy flooring cost calculator builds the whole floor up coat by coat.
Common mistakes
- Using a light accent-broadcast rate as if it were the full-saturation rate, when 0.5 lb/ft² is specifically the refusal rate, not a light dusting
- Treating double broadcast as one thicker coat with extra quartz instead of two full, separate broadcast cycles
- Not accounting for aggregate size or broadcast technique shifting the actual consumption rate
- Rounding bag count down instead of up, rather than ordering the full bag the calculator gives you
Frequently Asked Questions
When do I need double broadcast instead of single?
Double broadcast is typically used for high-traffic commercial floors, outdoor areas, or anywhere that needs extra film build. Slip resistance depends on the aggregate size and the topcoat, so specify it either way. It means two full epoxy coats, each broadcast to refusal, rather than one thicker coat with extra quartz.
Does "broadcast to refusal" mean exactly 0.5 lb/ft²?
0.5 lb/ft² (2.44 kg/m²) is the typical full-saturation rate for standard broadcast-grade quartz, and the calculator’s default. Actual consumption varies with the substrate, the grade of aggregate and broadcast technique, so always confirm the rate against your specific product’s data sheet.
What’s the difference between a quartz system and a flake system?
Quartz uses colored sand-like aggregate broadcast to full saturation for a uniform, slip-resistant, commercial-grade texture. Flake uses larger vinyl chips, also broadcast to refusal in a full system, but chips are far lighter than quartz, so the weight per square foot is much lower. The look is decorative and less uniform. Different materials, different weights per square foot, different typical markets.
Can I blend quartz colors like a custom flake blend?
Not with this calculator. Quartz is usually ordered as a pre-blended color from the manufacturer, though some manufacturers offer custom blends, rather than mixed on site the way flake colors are.