Things You'll Need
Thick rubber gloves
Professional buffer/scrubber (can be rented)
Small nylon bristle brush
Garden hose to the area
Broom and dustpan
*opt. plastic sheeting
Plastic watering can
Glass measuring cup
Stiff push broom
Garage floors take a lot of abuse and generally, when installed by a builder or contractor, the concrete will be sealed to protect the surface from common garage spills such as oil. The sealer penetrates the porous concrete and prevents stains from seeping deep into the concrete. Over time the sealer wears thin or other surface coatings may be more appropriate for the type of use and wear by the homeowner. Removing sealer from a garage floor is not easy but it is essential in order to create a proper base for other flooring surfaces.
Remove everything from your garage to a location not on your driveway since you will be washing acid out of your garage onto your driveway. You may be able to cover some wall items with plastic sheeting and tape but keep in mind that you will want to clean the floor all the way to the foundation walls.
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Put on your protective gear and make sure you and your assistant have no exposed skin. Test your floor for sealer by mixing equal parts muriatic acid and water in your glass measuring cup. Pour a small amount on the floor in an area that has been covered by stuff for a long time. If the acid bubbles up it means the floor wasn't sealed so you won't have to strip it with acid. If it puddles then you have to strip it off.
Sweep your floor thoroughly and use a little household cleanser or paint solvent to clean up any big stains or spilled paint. Use your scraper and small brush to loosen anything stuck to the floor.
Power wash the floor to remove anything water can clean. You can use a cleanser in your power wash to add to your cleaning power.
Measure and pour water into your plastic watering can. Measure and pour an equal amount of muriatic acid - pour the acid directly into the water so that it doesn't touch the plastic). Use a painter's stick to mix the fluid well.
Apply the mixture to a section of floor at the back of your garage. Have your assistant stand outside when you first start up the scrubber. Some scrubbers are powerful and will jerk you around a bit until you get the feel for them. Once you feel comfortable, scrub a section of garage in one direction and then go over the same section of floor at a right angle to your first pass.
Move to another section of floor and repeat. Your assistant should be washing the acid toward and out of the garage doors using just water and the power washer. Repeat this over the entire floor.
Use the power washer to rinse the entire garage out again.
Starting at the back of the garage pour ammonia in a line on the floor and using the stiff push broom to scrub the ammonia across the floor. This will neutralize any remaining acid and further clean the surface.
Use the power washer to rinse the garage floor thoroughly and you are ready to apply your new garage floor coating. Be sure to completely dispel the muriatic acid from any puddles on your driveway as it may do damage. A good wash of your driveway will reduce the ratio so much that it will do no further harm.
Prevent children and animals from being outside during this job as the acid used is caustic. Protect anything near your driveway that might be damaged by over-spray. A great deal of the work on this job is in the preparations taken. Protect your shrubbery as well. There are natural products like lime and baking soda that counteract acids. Soak your yard with these products in advance so that any acid will dilute on contact with the soil.
Treat any contact with muriatic acid immediately by flushing the affected skin with water and sprinkling with baking soda. Follow this up by going to your local emergency clinic at once.