Who has installed a 2-post lift on a residential slab?
07-07-2010, 08:29 PM
#1
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Who has installed a 2-post lift on a residential slab? I'm looking at getting a two-post lift from an out of business car dealership. I live in a regular housing tract, so I'm sure my slab is no more than 4" thick, and lift specs call for a minimum of 4" steel reinforced. I've heard of people just cutting out, let's say a 2' square hole around where the lift posts will be anchored, and pouring nice deep concrete in that area, rather than a whole new slab. Is this safe?
07-08-2010, 01:48 AM
#2
2 post lift here in my house just got done back in Feb.10.you need at least 2foot deep where the post will be anchored and dont forget to reinforced it with reebar before you pour the concrete.I use a 2500psi concrete from cement truck since we were doing our whole yard.be safe do it right.ask around maybe from where your buying the lift.
07-08-2010, 09:43 AM
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I ve got two two posts lifts in my garage. I poured my floor, but at the time of the pour I only planed on one lift. The thick part of the floor was 9-10 inches. The lift that was installed for me, I asked that very question. How thick? The guy said they ussually drill all the was through, and many many many times the commercial floors are only 4 inches. He said they are so bad that they often times epoxy the anchors in.
I could see pouring a deep footer if you cut a section out, but I would go a lot bigger then 2x2.
I ve had my cummins ram dually on my big two post where the floor is 9 inches or so, and I ve used it to lift my 50 ft trailer. My used lift wont lift over about 4000lbs.
I could see pouring a deep footer if you cut a section out, but I would go a lot bigger then 2x2.
I ve had my cummins ram dually on my big two post where the floor is 9 inches or so, and I ve used it to lift my 50 ft trailer. My used lift wont lift over about 4000lbs.
07-08-2010, 09:58 AM
#4
http://www.rotarylift.com/uploadedFiles/FAQ1.pdf
According to that link Rotary requires only 4 1/4" of 3000psi concrete for it's 10,000lb 2 post lift. It also specifies a required torque for the anchor bolts and tells you how to repair the slab if the anchors can't hold the required torque.
I would just drill through the existing slab and see how thick it is. If you have 4" then I would use it as is because 4" of cured concrete is better than 6" of green concrete.(It takes 7 years for concrete to fully cure.)
According to that link Rotary requires only 4 1/4" of 3000psi concrete for it's 10,000lb 2 post lift. It also specifies a required torque for the anchor bolts and tells you how to repair the slab if the anchors can't hold the required torque.
I would just drill through the existing slab and see how thick it is. If you have 4" then I would use it as is because 4" of cured concrete is better than 6" of green concrete.(It takes 7 years for concrete to fully cure.)
07-08-2010, 10:39 AM
#6
Concrete hardens and gains strength as it hydrates. The hydration process continues over a long period of time. It happens rapidly at first and slows down as time goes by. To measure the ultimate strength of concrete would require a wait of several years. This would be impractical, so a time period of 28 days was selected by specification writing authorities as the age that all concrete should be tested. At this age, a substantial percentage of the hydration has taken place.
Taken from here: http://www.cement.org/basics/concretebasics_faqs.asp
That site does not say seven years, but I have seen it from more than one source. That's just the first site that came up in my google search. I figured I better post a little bit of proof before everyone goes crazy and starts calling me an idiot!
Taken from here: http://www.cement.org/basics/concretebasics_faqs.asp
That site does not say seven years, but I have seen it from more than one source. That's just the first site that came up in my google search. I figured I better post a little bit of proof before everyone goes crazy and starts calling me an idiot!
And that IS good to know! 
07-08-2010, 01:57 PM
#8
I'm looking at getting a two-post lift from an out of business car dealership. I live in a regular housing tract, so I'm sure my slab is no more than 4" thick, and lift specs call for a minimum of 4" steel reinforced. I've heard of people just cutting out, let's say a 2' square hole around where the lift posts will be anchored, and pouring nice deep concrete in that area, rather than a whole new slab. Is this safe?
Cutting out a section and re-pouring will weaken it IMO.
I poured my own slab & I had it around 6-8 inches deep where the posts where going to be. BUT I made sure my steel wasn't going to be in the way for drilling the holes for the anchor bolts.
07-08-2010, 03:04 PM
#10
Curing is a chemical process that requires that there be some moisture to continue, basically you're growing crystals in the concrete and the longer it grows and knits together the stronger it is, and gives off heat as it happens (that's why you can pour a concrete slab blow freezing and not only does the water in it not freeze but it actually gets warm). Curing time depends on thickness and humidity, you can extend it by covering it with a plastic tarp, and that will make it stronger. Supposedly there is so much concrete in the hoover dam that it's still wet and curing inside...
You could run into all sorts of weirdness with your "stock" garage slab... in my case, all the houses that the builder that built ours got an 8-10" rebar reinforced slab, supposedly 3000# concrete, that would pass the standards for putting just about anything on it, but that's because they built the whole house with a pit in the garage foundation and use that space to dump all the construction debris, the covered it over when everything was built and they were grading the yard and put that slab on top, I'm guessing it's so over spec to make sure that if any of the trash under it moves whatever you have sitting on the slab doesn't go through the floor... OTOH, I have a 15' ceiling in there also...
You could run into all sorts of weirdness with your "stock" garage slab... in my case, all the houses that the builder that built ours got an 8-10" rebar reinforced slab, supposedly 3000# concrete, that would pass the standards for putting just about anything on it, but that's because they built the whole house with a pit in the garage foundation and use that space to dump all the construction debris, the covered it over when everything was built and they were grading the yard and put that slab on top, I'm guessing it's so over spec to make sure that if any of the trash under it moves whatever you have sitting on the slab doesn't go through the floor... OTOH, I have a 15' ceiling in there also...
07-08-2010, 06:02 PM
#11
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Well it seems like it'd be relatively easy to get the slab up to par. How hard are these things to put up? The dealer that is selling them will disassemble it and help load it on my trailer, then it's up to me to set it up a home. It sure looks like a HEAVY mf'er! How'd you guys put them up?
07-09-2010, 12:17 PM
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I would just use the slab you have, as long as its not full of cracks. just make sure you place the vehicle on the lift so it's balanced.
Last edited by blown402; 07-09-2010 at 04:17 PM.
07-09-2010, 12:58 PM
#15
I drilled mine and found it was 3.5" I have a 9k Eagle two post. I cut out approx 4'x10' section. Drilled into the existing slab and tied rebar to the new slab that was poured about 12" thick.
Better safe than sorry. Only cost about $400 doing most myself.
Better safe than sorry. Only cost about $400 doing most myself.
Last edited by LS1NOVA; 09-10-2010 at 05:12 PM.
07-10-2010, 03:39 AM
#17
no not really.elec. here that does commercial and residential wants $2800 bux to do it and mentioned about getting a permit.plus I had to move my main power line coming to the house moved to the side so it wont enterfere and out of the way of the lift.like said better safe than sorry.
07-10-2010, 04:01 PM
#18
no not really.elec. here that does commercial and residential wants $2800 bux to do it and mentioned about getting a permit.plus I had to move my main power line coming to the house moved to the side so it wont enterfere and out of the way of the lift.like said better safe than sorry.
07-10-2010, 10:11 PM
#19
my main power line was right over my lift so I had to move it to the side of the house.need a permit to do that but didnt have to since I knew the elec. through my hookups.now it needs a roof.saving $ for that one.lift is operational.no more workin on my back.
