The garage has got to be the number one of all the floors in your house where level matters the least. You are good to go as long as you can get the car in and it stays in place. It is also true that even level critical services like the washer and water heater can be leveled individually. 

Garage Floor 

However, when two critical scenarios happen, an out of kilter garage floor may require leveling. First is when the floor is so out of level that makes the garage door unable to meet the edge of the floor. The second and most critical one when the garage floor has begun to tilt back toward the house. This will cause the water to flow towards the house. 

    Apply Leveling Compound  

To fix a floor that is uneven, a leveling compound is the classic and easiest way. You just need to lift and level properly. In fact, you just need to pour the leveling compound out and letting it find its own level. It is a little less simple for garages. 

Some home improvement guides suggest for troweling the concrete patch compound across the entire area of the floor. It can be difficult for novices to achieve such results like two inch gain over 20 feet even though it is technically a good idea and perhaps a viable one for professional masons. 

If you might have a section that has cracked off and is now sloping down, you can apply a leveling compound as a spot fix. Since they are fairly localized, dips and sags are also great candidates for concrete leveling compound. 

For this product to adhere properly, all areas that will receive the leveling compound must be roughly clean. Abrading the concrete may be necessary because motor oil can be difficult and even impossible to clean from concrete. 

    Slab Jacking With Slurry 

To correct the tilt of an entire concrete slab floor, you can use a method called slab jacking. This method is quite expensive and you cannot do this on your own. However, this is much cheaper compared than demolishing and rebuilding your garage. With only minor touch-ups required if the slab jacking efforts succeed, it only utilizes your existing concrete slab. 

Concrete raising is another method wherein a matrix of holes, each about three inches in diameter is drilled directly into the concrete and then a slurry of sand, ash, and gravel is injected into the holes. Technicians have to make sure that the slab is supported in all areas by test and intuition.   

It can crack the slab by forcing it upward too much if one area gets too much push. It can also be left unsupported and can eventually crack and break if one area gets too little slurry.  For the slurry to cure to its eventual strength, it will take about one day. 

    Slab Jacking With Polyurethane Foam 

Since technicians can better predict the expansion of the polyurethane foam, you can use foam injections that are similar to slurry injections but are considered effective. More projects need to be injected under the slab and the slurry injections require larger injection holes.