Worked case: a three-car polyaspartic flake garage on a new tract slab in Audie Murphy Ranch — what happens and what it costs

The scenario

Picture a three-car garage in a tract home built within the last few years. The room is about 32 by 22 feet, roughly 700 square feet, with a smooth builder-troweled slab, a few hairline shrinkage cracks near the control joints, no old coating and a faint sheen where the builder's curing compound is still on the surface. Two steps lead up to the house door. The garage faces west, so the afternoon sun runs deep into the room.

The family has just moved in. The slab was poured well before that, but the owner's first question is whether it is ready. Manufacturers commonly advise waiting at least 28 days after the pour, and up to 60 in some conditions, and they also say the reading matters more than the date. The owner wants a speckled floor that looks quiet from the street, a few colors picked to match the cabinets and finished steps at the house door.

The starting conditions at a glance:

• Size: three-car garage, about 700 square feet
• Slab: sound, new, hairline cracks only, builder curing compound or sealer still on top
• System: epoxy base with a custom flake blend and a polyaspartic top coat
• Setting: a master-planned tract with an association, a west-facing door and a July mean high near 97°F

What the job involves

1. The installer asks when the slab was poured and whether a builder sealer was applied, then runs a moisture check, a calcium chloride kit or in-slab humidity probes, since the installed system sets the level the slab may read.
2. The owner sends the management company a short note naming the address, the dates, the fact that the work is inside the garage, where the installer parks and why the door stays open for ventilation; the association decides what applies.
3. A diamond grinder with a dust shroud and a vacuum takes off the curing compound and opens the surface, and the hairline cracks are routed, filled and ground flush.
4. The start is set for early morning, because a warm slab and warm air shorten the working time of the polyaspartic top coat; the installer checks the slab temperature and the dew point before mixing.
5. Primer and a pigmented epoxy base go down in sections, the custom flake blend is broadcast by hand until the base is covered, and the two entry steps are coated with the same stack.
6. After the base has cured, loose flake is scraped and swept, the polyaspartic top coat is mixed in small batches and rolled quickly, and the data sheet sets the day for foot traffic and the day the cars return.

Materials and prep

• Moisture testing kit (calcium chloride) or in-slab relative humidity probes
• Floor grinder with diamond segments, dust shroud and vacuum, plus a hand grinder for the two steps
• Primer, tinted epoxy base coat, vinyl chips blended to the owner's palette and a polyaspartic clear top coat
• Notched squeegee, roller covers, a flake hopper, cleated shoes and box fans
• Infrared thermometer and dew point meter for choosing the start time

Add-ons often paired with this job

• Coat the stem wall (the low wall around the garage) — +$150–$400. Wrapping the short curb wall in the same system gives the room a finished perimeter.
• Move the garage contents out and back — +$150–$400. Clearing cabinets and bins before the grind and returning them afterward is a flat line the owner can handle.
• Extra crack or joint repair (many cracks) — +$150–$450. Should the control-joint hairlines multiply, a separate flat line pays for the extra routing and filling.

Why it is done this way

The hybrid stack splits the work between layers. Epoxy bonds well to a ground slab and gives the installer time to broadcast the flake while the base is wet; a polyaspartic top coat is generally more UV-stable and cures faster, which fits a garage with a west-facing door. That is the reason to pay $6–$10 per square foot instead of $5–$8.

The wait is the part of the story most owners have not heard. A tract slab can be a few months old, and a slab can be cured and still hold too much moisture for a coating. In-slab humidity probes are named as the most accurate test, and the data sheet of the chosen system names the limit. The calendar says when to test, and the number says whether to coat.

Heat shapes the day. With July and August mean highs near 97°F and 98°F, a fast-curing top coat has less working time on a hot afternoon, so the start time matters more than the choice of system. A polyaspartic top coat can be installed in one day on a dry, workable slab, but vehicles return only after the time on the data sheet, often 24 hours to several days; the cars park outside until then.

The association note is part of the job even though the floor is inside. The open door and the installer's truck at the curb are what the rules usually cover, and the CC&Rs decide.

The alternatives that were weighed and set aside:

• Epoxy throughout would cost $5–$8 per square foot but can amber in sunlight at an open door.
• Waiting longer before coating costs nothing but time, and is the right answer if the moisture reading is high.

What would change the price

• A moisture reading above the system's limit calls for a vapor-barrier primer, the damp-slab line of $2–$4 per square foot, or a longer wait.
• More than a few hairline cracks adds the crack line of $1–$2 per square foot or the flat extra-crack line.
• A two-car garage instead of a three-car changes the area to about 400 square feet, and every per-square-foot line scales with it.
• A start pushed to a hot afternoon can force a smaller batch size and a second crew member for the top coat.
• Stem walls, steps and moving the contents are flat add-ons.