2 post car lift...

[bigbert]

Ready to install a 4000kg 2 post car lift and the concrete is too thin and not the correct psi

Is it better to have 2 pads cast at 4 wide x 5 long x 2 feet deep for each post

Or

4 wide x 16 long x 1 foot deep spanning the two posts

Not sure what is under the existing slab but I think it would just be earth.

Thanks

 

[firebirdparts]

I prefer going all the way across.

 

[Daedalus]

What are the lift manufacturer's requirements?

 

[bigbert]

Hi there,

If I went across with the pad how far past the post would I need to go on either side, a good foot past either post looks good.

Thanks.

 

[bigbert]

They say a 150mm thick slab, but not got that.

 

[CraigStu]

I'd go all the way across so you have one large pad. When you cut out the existing rectangle and start digging, dig back under the edges of the existing floor 6-8 inches so the new pad actually flows underneath the existing floor.

 

[pattenp]

The width of my 9000lb 2 post lift is a little less than 12ft and the manufacturer calls for a pad 14 feet X 4 feet X 12 inches thick keyed into original slab.

 

[SJW]

Who is the lift manufacturer? What are your actual concrete specs?

Many lift manufacturers whose specs I've looked at -- BendPak and Rotary, to name a few -- call for from 4 to 4.5 inches of concrete depth, 3000 psi for up through a 10,000 pound, two-post lift. Mohawk calls for deeper and stronger.

To answer your original question, having a single long slab is stronger than two pads, in general. Make sure, as pattenp points out, to key the new slab into the existing slab.

As for width of the slab, I would go at least two feet wider than the full width of the lift, which would probably be back of base plate to back of base plate.

 

[bigbert]

wow this slab is getting bigger.

Have looked at other people's slabs / pads they have put in and they are not that big at all.

 

[brownbagg]

i would do ten feet by 16 feet, four feet thick

 

[Lucid Moments]

The earth's crust is only about 3 to 5 miles thick depending on your location. That is barely thick enough to be truly safe. You will also need anchors that extend all the way through the crust into the mantle.

 

[bigbert]

Sounds like I maybe should get the floor torn up and get it re poured again to a 4" slab with fibre through it. Or sell the lift and go back to crawling under everything again...

 

[rburke65]

Mohawk has a good pictorial and specs on their web site. But I’d do the 4’x10’ single pour. Rebar. Fiber won’t add to the quality

 

[Lucid Moments]

Sounds like I maybe should get the floor torn up and get it re poured again to a 4" slab with fibre through it. Or sell the lift and go back to crawling under everything again...

TBH I wouldn't go to either of those extremes. Up to a point the more concrete you have the more secure it will be, but if you cut out a section maybe 1 meter wide by 2 meters long where each post is going to be, and dig under the existing slab a little it should be more than stable.

Some people on here tend to go to extremes.

 

[TimTheToolManTaylor]

The earth's crust is only about 3 to 5 miles thick depending on your location. That is barely thick enough to be truly safe. You will also need anchors that extend all the way through the crust into the mantle.

I prefer through to the core myself.