Reinforce the floor for 4 post lift?

[rarebreed]

So I am getting quotes to add a third bay to my existing garage and it's WAY more than I want to spend. So I am going back to my original plan to put in a high lift door kit with a jack shaft opener and a 4 post lift. I have heard from a few of the contractors stating that I will need to reinforce the floor for the 4 post lift so that the slab does not crack? The garage floor is a standard 4" slab. My question is if any of you have ever had issues with a lift cracking the floor or if you recommend a way to add in the extra concrete in the areas where the post's will sit on the floor.


Any advise is appreciated.

 

[rsanter]

Most 4 post lifts do not need the floor reinforced but check the manufacturer specs.
You could always put a 14"x14" by 3/8 thick steel plate under the legs to spread the load if it is an issue

Bob

 

[rburke65]

If your floor is in decent condition, you should have no problems with a 4 post lift on your concrete floor. At 4,000 psi, concrete can withstand a lot of weight. That's 144 times that in a given 12" by 12" area per each post! I think you will be fine. IMO.

 

[Stuart in MN]

You shouldn't need any extra reinforcement for a four post lift, as mentioned above they spread their weight out over a larger area than a car.

 

[malibu101]

I ain't not no engineer. :tard:
But I look at it this way- The car sits on 4 tires and the post sits on 4 areas about the same size as a tire footprint.
Add the weight of the car and the weight of the lift and the total weight is probably about equal to a loaded pickup truck.
Would you park a loaded pickup on the concrete?
See what I'm getting at?

 

[holdover]

the pads for a typical 4 post are 12 X 12 X 4 = 576 sq in. A typical tire contact patch area is let's say 7 X 8" X 4 = 224 sq in, even adding for the weight of the lift not a problem with even 3500 psi cement. The contractors you spoke to must be hungry...

 

[Rookie2]

A friend installed one outside on asphault and it's fine. AND it is made to pick up and roll to another location.

 

[rarebreed]

That was my thinking as well. Also, have any of you installed a high lift door kit? I don't need to reinforce the header above the door when I move it up, right? same contractor says that I would need to do that and wanted $2500 to do all the work with the high lift kit. He's nuts if he thinks I am going to pay that much.

A high lift kit is all of about $350 plus a lift master jackshaft opener, right?

 

[Dakota00]

The header above the door doesn't get touched. A high lift conversion cost about $350 installed which includes extension tracks, new springs, bigger drums and cables.