How Thick Concrete for Car Lift?

Having a car lift whether it’s a 4-post or a 2-post is so advantageous, there isn’t anything comparable. The car lift efficiently boosts the workflow of your workshop; enables easy access underneath and provides extra space in the garage. While everything is true, there is one important thing people tend to forget; the thickness of the concrete floor where the lift stands.

If you want to get all the benefits a car lift provides, you need solid ground. Not just any solid ground, a concrete floor with a minimum of 5 inches of thickness. Technically, you can place a car lift on any strong surface but there is a lot more to that than meets the eye.

Each type of car lift will have different thickness requirements on the Car lift guide. Some lifts can stand on the 4-inch thick floor and others require up to 12 inches of thickness. Have you seen the truck lift? Those machines lift around 6,000-10,000 pounds.

But for a car lift, you don’t need to get that serious about the floor thickness. Most cars weigh around 2500 – 3500 pounds that means you can get away with 5-6 inches of floor thickness without any issue.

how thick concrete for car lift

What is the difference between a concrete slab and a cement slab?

Concrete slab and cement slab, both are very important parts of the masonry work in construction. However, people tend to think these two different types of floor are the same. Indeed cement is the main ingredient for both compounds, but they are not the same.

The cement slab consists of only Portland cement and water. Sometimes, it also has plaster to make the surface smoother. The standalone cement slab includes material from limestones like silica sand, clay, and other stuff like calcium, aluminum, and so on. 

If you look closely, you will see most construction of a driveway and various walkways. Because of the smooth finish and low-cost construction, it’s a popular choice among people. However, cement slab is not good with weights and easily cracks over time.

On the other hand, the concrete slab is a mixture of various aggregate or gravel, sand, water, and most importantly Portland cement. The ratio of each ingredient varies depending on the use cases. In general, the major portion of the mixture is the gravel and the rest 10-30% is cement.

Concrete slabs are stronger and can withstand a tremendous amount of pressure. Whether it’s for a workshop floor with heavy equipment or a storage facility, concrete floors won’t disappoint you. The most amazing part is it will last a lot longer than cement floor in any environment or the usage cases.

How to pour a concrete slab for a car lift?

If you are planning to install a car lift in your garage make sure you have a concrete floor beforehand. Only cement floor won’t do you any good as it will be holding a lot of weight. You need to prepare the concrete floor and give it time to cure itself at least 28 days. In the meantime, you can choose a suitable car lift for yourself.

Here is a quick guide on how you can pour a concrete slab for a car lift:

  • Step 1: First, mark the surface where you want to make a concrete floor. Most post lifts have a width of 11-12 feet. So keep in mind not to take less than that.
  • Step 2: Gather all your equipment for the digging and ingredients for the concrete mixture. Such equipment includes a jack hammer, shovel, rebar wirings, reinforced steel bar for the structure, and so on. If you hire professionals, you don’t need to worry at all.
  • Step 3: Break the current floor structure and dig a hole around 7-10 inches. Even if your lift maker requires a 4-inch concrete floor, getting a few inches extra only makes it stronger and lasts longer. It’s definitely worth the cost considering the application.
  • Step 4: Fill out the first 1 or 2 inches of the bottom with sand and level as best you can. Now make a square mesh with a steel bar covering the whole place. Make sure to connect each end of the bar with the existing floor structure; do a sideway drill if you have to.
  • Step 5: Once you have the steel bar placed evenly, it’s time to pour the concrete mixture. Do not try to hand mix the concrete, use the wheelbarrow to mix the ingredients uniformly.
  • Step 6: Slowly pour the mixture on the blank space up to the level of current floor height. You can also place a half-inch wooden frame around the slab which will give you space to expand on temperature fluctuation. That way it won’t crack so easily. Now let it rest for around one month before installing a car lift.  

How thick does concrete need to be for a 2 post lift?

The rule of thumb for 2 post car lifts, the concrete floor needs to be at least 5 inches thick or more. The anchor bolts that come with the post are around 4-7 inches long. To get good contact with a floor that is 5 inches thick is imperative. Anything less would put you at risk of losing anchor grip at the base of the post. 

How thick does concrete need to be for a 4 post lift?

Just like the 2 post lift, you need a similar 5-6 inch thick concrete floor. Remember the 4 post lift is heavier and covers more ground on the floor. So the thickness needs to be similar under each postbase. Each post base has 4 or more bolt holes that you will put the 5-7 inch anchor bolts on.

How thick does concrete need to be for a portable scissor lift?

Most of the portable scissor lifts, don’t use anchor bolts as the post car lift. That means you don’t have to make drill holes on the floor. But you are still lifting heavy cars like 2500-3000 pounds that call for a sturdy concrete surface. To be on the safe side it’s best to have a 4-6 inch thick concrete floor so it doesn’t crack under pressure.

Why does concrete thickness matter for car lifts?

To have a solid bond with the concrete floor, thickness matters the most. Anchor bolts that you use in the postbase have specific functionality. It clamps into the drill hole by expanding the loose parts of the bolt. If your concrete floor is anything less than 5 inches, the bolt won’t have a solid grip on the floor.

Can a car lift fall?

Most car lifts come with a top bar that connects two posts. Unless the lift has a car on it and the base anchors severed the connection with the floor your car lift won’t fall. If one of the posts is working and the other one is not as much as the first one, your car will topple along with the post.

Why do cars fall off lifts?

The main reason for that is a crooked post that is not functioning as the other one. Both the posts need to move at the same rate when lifting. This happens due to a malfunction in the lifting mechanism.

In addition to that misplacement of contact pads under the car is another reason cars fall off lifts. If you place it at the wrong point, it won’t clutch the car securely. Also when you try to lift cars that exceed the rated lifting capacity, they will fall after a failed attempt.

Frederick James is an expert mechanic with years of experience under his belt. He excels in diagnosing, troubleshooting, repairing, and modifying everything related to automobiles including but not limited to cars and pickup trucks. Read more...

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