help with lift footings

Hi Guys,

I am setting up my new shop on a not so good concrete floor (cracked floor). At the moment I cannot afford to pour a new floor, and I would like to install/pour footings for safety. I am on a tight budget and have to do it myself.

I am a mechanic by trade, and know nothing at all about how to install a footing. I am thinking it cant be that hard to do.

I have access to a jackhammer.

Does anyone have a step by step way to do this? Once again, I would need EVERY step...including making sure the footings are level.

The lift is a 10,000lb rated 2 post lift. The brace for the lift goes across the top....open span across the bottom.


Thanks in advance for the help.

Pete

I recommend shooting an email to the 2 post lift company. They should have a suggestion as to what size and depth to make the new footing and possible rebar reinforcing. When we detail thickened footings to be cut into existing slabs we try to 'pin' the slabs together if the thickness of the existing slab allows it. By pinning I mean we have them drill and epoxy set a #4 rebar into the existing slab that will go into the existing about 6" and stick out about another 6" and place these about 12" OC (on center). If the existing slab is too thin or breaks when trying to drill for rebar pins then we typically have the thickened slab undermine the existing slab by about 6" so that the existing slab basically sits on top of the new thickened footing. I am not a structural engineer so these are only recommendations and I strongly suggest talking to the company providing the 2 post lift.

An easier way to remove concrete is to rent a concrete saw. I like the kind you can walk behind. Make several cuts to create 6" cubes. After you've made the cuts break the cubes apart, if they aren't already loose, with a sledge hammer. The 6" cubes are much easier to handle and move than concrete that's been busted up with a jack-hammer.

I'm not a structural engineer, nor an expert on lifts, so take my suggestions with a grain of salt. If you cut a rectangle 14ft wide and 3 ft front to back and 12" deep, you would need less than 2 yards (1.56 yards) of concrete to refill the hole. Concrete in my neighborhood (Massachusetts) costs approximately $100 per yard. 5000psi concrete costs only a few dollars more. Because it is a small amount, there may be delivery charge. You can easily make a rectangle form out of 2x framing lumber. Set the form level in the hole in close proximity to the height of your existing floor. When the concrete is delivered use another 2x or other stiff, straight material to scree (drag) the concrete level with the top of your form. To add additional strength to the concrete lay steel reinforcement rod horizontally into the concrete. Set the rod 1/3 of the way off the bottom (if the hole is 12" deep, the rod should be 4" from the bottom). Space the rod 4" to 6" apart criss cross.

Approximate costs:
Lumber and #4 (1/2") reinforcement rod $100
Walk-behind concrete saw rental $55 for 4 hours.
2 yards of concrete $200 plus delivery fee (?)

The most difficult part of the job will most likely be getting rid of the old concrete.

I have a BendPak 4 post. The manual that came with it has a section on minimum concrete requirements. You should be able to find a copy of the manual for your lift online. Good Luck.

I have recently installed an Atlas 2 post lift, the concrete specs and instructions are on their website. They call for min. 4" thick 3000lb mix, I blocked out two spots 3'x3', 12" deep in my slab. I sometimes overdo things.....
I think Jlbc212 has the right direction on this.

Lots of info on this site on lift/concrete requirements, but what does your lift mfg. Require? Goog is your friend as well as YouTube on concrete floors. This isnt something you aregoing to learn by reading though. You wont have all week to place a load of concrete. Good luck!

59chief said:

I have recently installed an Atlas 2 post lift, the concrete specs and instructions are on their website. They call for min. 4" thick 3000lb mix, I blocked out two spots 3'x3', 12" deep in my slab. I sometimes overdo things.....
I think Jlbc212 has the right direction on this.

Click to expand...

It may be a bit of an "overkill" but it is far better to have more conrete than you need than not to have enough. Besides that, the cost of the extra concrete is not some crazy stupid price.

Just finished doing the same. The slab I poured is based on the spec for a 7000lb lift. Document links are in the thread:

http://www.garagejournal.com/forum/showthread.php?t=265806