A floor grinder is hired as a system, not a machine: the grinder, the diamond tooling that matches the concrete, and a dust extractor that is not optional on any occupied job. Single-head walk-behinds commonly advertise $100 to $250 a day, with a HEPA vacuum adding $40 to $90. Which diamonds you fit changes the result far more than which brand of grinder the yard happens to stock.
Pick the disc size by the room, not the price
A 5 or 7 inch hand grinder is for edges, stairs and the last inch against a wall. A 10 inch single-disc walk-behind suits a garage or a small shop. A 20 to 30 inch planetary machine covers a warehouse bay in a session but needs three-phase power and will not turn in a bathroom. Most jobs need two machines, not one.
The diamonds do the work
Soft-bond segments cut hard concrete and hard-bond segments cut soft concrete, which is the opposite of what most first-time renters assume. Coarse metal bonds strip coatings and level high spots; fine resin bonds polish. Tooling is billed separately, often per set and sometimes on wear, so tell the counter what is on the floor now and what you want afterwards.
Dust control is a rule, not a courtesy
Grinding concrete releases respirable crystalline silica, and the federal construction standard sets out a dust-control method for handheld and walk-behind grinders: a shroud on the machine feeding a vacuum with a filter-cleaning mechanism, used indoors with ventilation. In practice that means renting the matched extractor with the grinder. A shop vacuum is not the same thing and will blind within minutes.
Check the power before delivery
Small grinders run on ordinary 115-volt circuits, but they trip breakers when a vacuum shares the line. From 10 inches upward you are usually looking at 230 volts single-phase, and planetary machines commonly want three-phase. Ask what the site has before booking, because a machine that cannot be plugged in still bills its day.
Questions people ask about concrete floor grinder rental
How long does it take to grind a garage floor?
A two-car garage with a 10 inch machine is generally a day for a single pass, plus edging by hand. Removing old adhesive, paint or a thick coating can easily double that, since those passes are slower and eat tooling.
Can I use a floor grinder to remove epoxy?
Yes, with coarse metal-bond or PCD tooling made for coatings. Standard grinding segments will glaze over on a soft coating and stop cutting, so name the coating at the counter and take the tooling meant for it.
Do I need a HEPA vacuum with a rented grinder?
For any indoor work, in practical terms yes. The dust-control method described in the silica standard for grinders is a shroud and a vacuum with filter cleaning, and yards hire the matched pair for that reason.