Two questions, one page. How many gallons of coating for a floor, and how many kits of patch for a crack or a spall. Both answered from Tri-Chem's own published figures, with a real material allowance so you order once.
How many gallons of coating?
Square feet. Measure the coated area, not the building footprint.
Volume solids and film build are pre-filled from the technical data sheet.
Percent. A 100% solids epoxy loses nothing to evaporation.
Mils dry film thickness. See the thickness guide below.
Percent. Tri-Chem's standard allowance is 10%. Raise it for open or badly spalled concrete.
Thickness above is per coat.
Order this much
— gallons
| Tri-Chem published coverage | — |
|---|---|
| Theoretical coverage at 5 mils dry | — |
| Practical coverage after 10% loss | — |
| Material for one coat | — |
| Total for 2 coats | — |
| Suggested order with 5% contingency | — |
Coverage figures are typical and depend on substrate condition, temperature, humidity and application method. They are a planning tool, not a guarantee. For a job you are quoting, confirm against the product's technical data sheet and talk to us.
How many kits of patch?
Feet.
Inches, at the widest point.
Inches. Measure it after chasing out — depth drives everything.
Square feet.
Inches. Published yields are quoted at ¼".
Count of similar repairs.
Inches.
Inches.
Inches.
Kit yields are taken from the technical data sheet.
Percent. Covers what stays in the pail, overfill and feathering.
Order this many
— kits
| Published kit yield | — |
|---|---|
| Volume to fill | — |
| With 10% allowance | — |
| Single kit holds | — |
| Kits required | — |
| Or master kits | — |
Kit counts are based on published yields and assume the void is filled solid. Irregular spalls, undercut edges and rough sawn joints consume more. For a job you are quoting, call 800.456.6255.
Part one
Floor coating coverage
Every coating datasheet quotes a coverage figure, and every one of them is quoting theoretical coverage: how far a gallon would go on a perfectly flat, non-absorbent surface with zero waste. No plant floor is that surface. Plan on losing around 10% to substrate absorption, surface profile and application waste.
Coverage starts from a fixed identity. One US gallon of liquid, spread one mil thick, covers 1,604 square feet. Everything else adjusts that figure.
theoretical coverage (sq ft per gallon) = 1,604 × volume solids % ÷ mils dry film
Volume solids is the percentage of liquid that stays on the floor once solvent or water has left. A 100% solids epoxy loses nothing, so what you pour is what cures. A product at 58.5% solids leaves a little over half the wet film behind as dry film, so reaching the same dry thickness takes roughly 1.7 times the material.
Film thickness moves coverage, not the product. Three of our four epoxies are 100% solids and cover identically at the same film build. The only reason their published figures differ is that they are specified at different thicknesses. Change the thickness and you change the material requirement proportionally.
Tri-Chem coating coverage
| Product | Solids | Thickness | Coverage | Typical use |
|---|---|---|---|---|
| 233 LV: Low Viscosity Epoxy | 100% | 5 mils | 320 sq ft/gal | Thin, tight coats; also a clear primer |
| 233 MV: Medium Viscosity Epoxy | 100% | 10 mils | 160 sq ft/gal | General-purpose build coat |
| Z-Poxy: 100% Solids Epoxy | 100% | 10 mils | 160 sq ft/gal | Durable plant floor coating |
| Z-Poxy HP: Novolac Epoxy | 100% | 20 mils | 80 sq ft/gal | Aggressive chemical service |
| 144NF: Water-Based Hybrid Urethane | 58.5% | 3–4 mils | 200–350 sq ft/gal | Low-odour topcoat and maintenance coat |
Read that as a thickness table. 233 LV covers twice as far as 233 MV because it goes down at 5 mils rather than 10 — that is what low viscosity buys you. Z-Poxy HP covers half as far for the same reason inverted, and that heavier build is what gives the novolac its chemical resistance. 144NF is the only one that is not 100% solids, and it is a topcoat, not a floor rebuild.
Choosing a film thickness
| System | Typical DFT | Where it belongs |
|---|---|---|
| Thin-film topcoat or maintenance coat | 3–4 mils | Recoating a sound floor, low-odour work in occupied areas |
| Thin, tight coat or clear primer | 5 mils | Abrasion and chemical resistance without building height |
| General-purpose build coat | 10 mils | Plant floors, light pallet-jack traffic, cleanability |
| Heavy build coat | 20 mils | Aggressive chemical service, wash-down, novolac |
| Self-levelling body coat | 40–125 mils | Forklift traffic, impact, floors needing rebuilding |
| Broadcast slip-resistant system | 60–250 mils | Wet process areas, ramps, aggressive exposure |
| Cementitious urethane | ¼–⅜ inch | Food and beverage, thermal shock, steam cleaning |
Cementitious urethane is specified in fractions of an inch because it is a mortar system, not a coating, and yield is quoted per unit rather than per gallon. If that is what your process area needs, see urethane cement versus epoxy and call a chemist.
Wet film and dry film
With a 100% solids epoxy the distinction does not matter — nothing evaporates, so wet film equals dry film. That covers 233 LV, 233 MV, Z-Poxy and Z-Poxy HP. With 144NF it matters a great deal.
144NF is specified at 3 to 4 mils dry. At 58.5% solids, reaching 4 mils dry takes roughly 6.8 mils wet. If a specification says "4 mils" meaning dry and the applicator reads it as wet, the finished floor is around 40% thinner than specified. Say which you mean, and check it on site with a wet film gauge while the material is still wet — once cured, verifying dry film thickness means destructive testing.
Part two
Concrete patch kits
Patch kits are sold with a coverage figure: so many square feet at a quarter inch. That is useful if you are skim-coating a floor. It is close to useless if you are filling a crack, because a crack has depth, and depth is what consumes material.
The question our people get asked most often runs like this. I have a 20 foot crack, about an inch wide, three inches deep. How many kits? You cannot answer that from a square footage figure without a conversion, which is why people call.
Here is the conversion. A kit is a volume. The published coverage is that volume expressed as an area at a reference depth.
kit volume (cu in) = published sq ft × 144 × reference depth (in)
A kit covering 24 square feet at a quarter inch holds 24 × 144 × 0.25 = 864 cubic inches, which is exactly half a cubic foot. Once you know that, every repair is arithmetic.
The 20 foot crack, worked through. 20 feet is 240 inches. At 1 inch wide and 3 inches deep that is 240 × 1 × 3 = 720 cubic inches, or about 0.42 cubic feet. Against a Perma-Fil single kit that is a little over four fifths of a kit at the top of the published yield range and a little over nine tenths at the bottom. So: one kit, and order a second if you cannot come back. Note how far that is from the intuition that a 20 foot crack must need a lot of material.
Tri-Chem patch kit yields
| Product | Yield at ¼" | Volume per kit | Aggregate | Use it for |
|---|---|---|---|---|
| Ranger Patch RD-12 | 8 sq ft | 288 cu in · 0.17 cu ft | 12 lb FS25 | Damp concrete, pre-measured single-repair kit |
| Ranger Patch RU-10 | 21 sq ft | 756 cu in · 0.44 cu ft | 18 lb RU | Cementitious urethane, high moisture tolerance |
| Ranger Patch RE-18 | 16 sq ft | 576 cu in · 0.33 cu ft | 24 lb FS25 | 100% epoxy repair, pre-measured kit |
| Z-Patch | 16 sq ft | 576 cu in · 0.33 cu ft | 24 lb FS25 | Heavy abusive traffic, expansion joints |
| Perma-Fil Cold | 21 sq ft | 756 cu in · 0.44 cu ft | 3.32 gal mixed | Low-temperature and freezer repairs |
| Perma-Fil High-Strength | 21 sq ft | 756 cu in · 0.44 cu ft | 36 lb FS25 | General high-strength floor repair |
| Perma-Fil Quick Set | 21 sq ft | 756 cu in · 0.44 cu ft | 36 lb FS25 | Fast return to service |
| Perma-Fil Damp Patch | 21 sq ft | 756 cu in · 0.44 cu ft | 36 lb FS25 | Damp and wet concrete |
| Perma-Fil Chemical Resistant | 21 sq ft | 756 cu in · 0.44 cu ft | 36 lb FS25 | Chemical exposure areas, novolac base |
| Perma-Fil master kit | 210 sq ft | 7,560 cu in · 4.38 cu ft | 360 lb FS25 | Ten single kits; large or repeated repairs |
Two things fall out of that. Ranger Patch kits are roughly half the volume of a Perma-Fil single, because they are built as self-contained pre-measured kits for one repair rather than as bulk material. And a Perma-Fil master is ten singles, so on anything over about nine repairs the packaging question is worth asking.
Measuring the repair
A crack or a sawn joint. Length in feet, width and depth in inches. Measure the width at its widest point rather than averaging by eye — cracks taper, and the wide end is where the material goes. If the crack has to be chased out and squared before patching, measure after that, not before.
A floor area. Square feet and depth. This is the case the published coverage figure already answers, provided you are working at a quarter inch. At any other depth the figure scales inversely: half the depth, twice the area.
Holes and spalls. Count them, take an average length, width and depth, and treat them as boxes. It over-estimates slightly on a rounded spall, which is the right direction to be wrong in.
Depth is where estimates go wrong, and it is always deeper than it looks. A repair that appears to be half an inch deep is frequently an inch and a half once chipped back to sound concrete. Chase it out first, then measure, then order. Ordering from the surface appearance is the single most common reason a crew runs short.
How deep can you place it in one pour?
Two inches is the recommended maximum in a single lift, across the patch line. Deeper than that, build it up in two-inch lifts. Crews do sometimes pour to four inches in one go and we would rather they did not — a deep mass of epoxy generates heat as it cures and has nowhere to shed it.
So the 20 foot crack in the example above, at three inches deep, is a two-lift repair. That matters more for scheduling than for material: the kit count does not change, but the job is no longer a single trip.
The minimum is an eighth of an inch. Below that you are skimming rather than patching, and the way to get there is to use less of the kit aggregate for a thinner, more flowable consistency. Note which direction that moves your order: less aggregate means less volume from the same kit, so a skim repair needs more kits per square foot, not fewer.
The same lever works the other way. Use all the aggregate in the kit and you get a trowel consistency for a deep repair. Hold some back and it flows and self-levels. The calculator assumes you use all of it, because that is what the published yields assume.
Before you order, either way
- Test for moisture. A coating over a slab pushing vapour will blister or delaminate however well you calculated coverage. Run ASTM F2170 relative humidity probes or ASTM F1869 calcium chloride and choose a product rated for the result. Some of our products are formulated for damp and wet concrete specifically. Most are not.
- Chase repairs out to sound concrete and square the edges. Patch bonded to loose material fails at the bond line regardless of its compressive strength, and a feathered edge is the first thing traffic finds.
- Check the film build or lift depth against the product. Coverage figures are tied to a stated thickness. If your specification calls for 10 mils and you are pricing a product published at 5, your material requirement doubles. On patch, deep fills may need more than one lift or aggregate extension — call before placing anything much over a couple of inches.
- Patch before you coat. Coating is not a levelling compound, and using it as one is the most expensive way to fill a hole.
- Order the whole job at once, from one batch. Colour varies slightly between production batches, and the difference is permanent under plant lighting.
- Order the spare. A kit or a pail is cheap. A second shutdown is not.
Common questions
Why does my actual coverage never match the datasheet?
Because the datasheet quotes theoretical coverage on a perfect substrate with no waste. On a real plant floor, plan on losing around 10% to substrate absorption, surface profile and application waste. The datasheet is not wrong, it is answering a different question.
What does "100% solids" mean for coverage?
That none of the applied liquid evaporates, so wet film thickness equals dry film thickness. Our 233 LV, 233 MV, Z-Poxy and Z-Poxy HP are all 100% solids. With a 58.5% solids product like 144NF you apply roughly 1.7 times the wet film to reach the same dry thickness, and need proportionally more material.
Why do 233 LV and 233 MV have different coverage if both are 100% solids?
Only because of film build. 233 LV is specified at 5 mils and 233 MV at 10, so 233 LV covers 320 sq ft per gallon against 160. At the same thickness they would cover identically. Low viscosity is what allows the thinner, tighter coat.
Why does Z-Poxy HP cover only 80 sq ft per gallon?
Because it is applied at 20 mils rather than 10. It is 100% solids like the others, so at equal thickness it would cover the same distance. Doubling film thickness halves coverage, and that heavier build is what gives the novolac its chemical resistance.
How do I convert square feet at ¼" into a volume?
Multiply the square footage by 144 to get square inches, then by 0.25 for the depth. A kit covering 24 sq ft at ¼" holds 864 cubic inches, which is half a cubic foot. That volume is the real specification — the coverage figure is one way of expressing it.
I have a 20 ft crack, 1" wide and 3" deep. How many kits?
That is 240 × 1 × 3 = 720 cubic inches, or 0.42 cubic feet. One Perma-Fil single kit holds 792 to 864 cubic inches depending on where the yield falls in its published range, so one kit does it with a little to spare at the top of the range and is marginal at the bottom. Order two if you cannot come back for a second attempt.
Why do Ranger Patch kits cover less than Perma-Fil kits?
Because they hold less material. Ranger Patch is built as a self-contained pre-measured kit sized for a single repair, roughly 360 to 540 cubic inches. A Perma-Fil single kit is around 790, and the master kit is ten singles. Different packaging for different jobs, not different performance.
Does repair depth change how much I need per square foot?
Directly and proportionally. Published coverage is quoted at ¼". At ½" you get half the area from the same kit; at ⅛" you get double. A small deep repair can consume more material than a large shallow one, which is why the square footage figure alone will mislead you on a crack.
How much extra should I order?
The 10% allowance covers normal absorption, mixing loss and overfill. Add 5% contingency on a clean, well-understood job, or 10% if there is significant cove base and detail work, many small separate repairs, or you cannot shut down again to finish.