Correct floor for Mohawk System 1 lift

[MarkyK]

Hi Everyone

I am looking for an advice on the installation of the Mohawk System 1 9000LB lift in my garage. This is a used lift that is already in my garage, in a free standing position.

Garage that I have is 24" long by 14.2" wide with sealing at 118". Garage is attached to the house.



Few questions that I have are:

1. How can I tell if my current slab in the garage will be sufficient, my floor is probably 30 if not 50 years old, as the garage was build originally with the house. How should I measure thicknes of the slab and how do I know if there were any rebbar used? Floor does look very good no cracks and seems level.

The Mohawk requirements for installing this lift are 4000 psi (27579.02 kPa) mix 4½”(11.43 cm)depth
Specs are from this document http://www.tecequip.com/pdf/sys-1.pdf

2. Is there any other tests I need to do to the concrete to make sure it is suited for the job

3. The place that this lift was removed from, had it secured to the steel plate with 8 bolts sticking out from it, that was buried in the concrete.
So my question is what kind anchor bolts do I need as I have none at the moment.

4. Maybe a stupid question, but please recomend on how I should inspect my floor to be absolutely certain it is perfectly level for the lift.

5. My garage is 14'2",. The lift posts will be installed at 12" from each other, so that would leave about a foot from the edges of the slab on each side, I want to make sure it is sufficient.

Thank you for your help.

 

[Fiberglass Fred]

1) You can rent a metal detector to see if you have steel in there.
Drill in a few random places to see how thick it is. If the drilling gets really easy after less than 4.5", then it's not thick enough.

Also, dig (outside) beside the slab to make sure they poured a beam. A 12" deep by 12" wide beam is typical of many slabs. (IE: the concrete should be thick near the walls). If there's no beam, then I wouldn't put a 2 post lift that close to the edges of the slab, even if Mohawk says it's okay.

2) I have to admit, that I have no idea how to determine the psi rating after the mud is poured. Hopefully someone else knows.

3) Mohawk should recommend the anchors you need.

4) $500 method: buy some surveying tools
$15 method: buy a 4' level at Home Depot. You could attach it something longer to make it more accurate.
$0.02 method: poor a cup of water on the floor and see if it all rapidly flows in one direction or another. (sorry, I couldn't resist)

5) Mohawk should probably have a spec for that too, but like I said in #1, if there's no beam, I wouldn't put a post that close to the edge.

 

[krooser]

Drill a hole and measure the thickness... there's no way to test the specs on the mix AFAIK so don't worry about it. I have friends who have lifts in very old buildings with unknown concrete specs and none have ever come down... there's always a first time but I doubt you'd have catastrophic failure... it would crack and give you some warning I'm sure.

You can level the lift using steel shims under the columns.

I used 1' diameter "Wedg-it" anchors on my old Weaver lift... use the largest you can... I've also used Redhead and Hilti fasteners, too.

Here's a link with LOTS of info... http://www.confast.com/

After the thing is in and operating you will realize that it's no big deal installing your own lift... honest!

 

[Dave Heacock]

Hi Everyone

I am looking for an advice on the installation of the Mohawk System 1 9000LB lift in my garage. This is a used lift that is already in my garage, in a free standing position.

Garage that I have is 24" long by 14.2" wide with sealing at 118". Garage is attached to the house.



Few questions that I have are:

1. How can I tell if my current slab in the garage will be sufficient, my floor is probably 30 if not 50 years old, as the garage was build originally with the house. How should I measure thicknes of the slab and how do I know if there were any rebbar used? Floor does look very good no cracks and seems level.

The Mohawk requirements for installing this lift are 4000 psi (27579.02 kPa) mix 4½”(11.43 cm)depth
Specs are from this document http://www.tecequip.com/pdf/sys-1.pdf

2. Is there any other tests I need to do to the concrete to make sure it is suited for the job

3. The place that this lift was removed from, had it secured to the steel plate with 8 bolts sticking out from it, that was buried in the concrete.
So my question is what kind anchor bolts do I need as I have none at the moment.

4. Maybe a stupid question, but please recomend on how I should inspect my floor to be absolutely certain it is perfectly level for the lift.

5. My garage is 14'2",. The lift posts will be installed at 12" from each other, so that would leave about a foot from the edges of the slab on each side, I want to make sure it is sufficient.

Thank you for your help.

Mark,

There are two sets of requirements to meet when anchoring a lift. The first is the manufacturer's and the 2nd is the building and safety's if you are going to get an installation permit. I would strongly suggest not getting a permit for a lift installation in a home garage or existing building as it could be very difficult with an existing unknown slab design.

Concrete hardens as it ages. 2,500 - 3,000 PSI is a typical commercial slab mix. If your slab is as old as you say, it could easily be over 4,000 PSI. The only way to tell for sure is to core drill a sample and have it tested but that is very expensive. If you have good uncracked concrete, I would just worry about anchor embedment at this point. Rebar will not effect the lift anchors pulling out, but it will improve the punching force the slab can take if a seismic event occurs. Inadequate rebar could lead to a cracked foundation at worst case. Sonar would be the only way to check for rebar and it still would not tell you the bar size, only it's spacing.

To see if you have the proper thickness, take a roto-hammer and drill a test hole near each column. Do not assume that the concrete is the same thickness at each location. Be careful not to apply too much pressure to the hammer drill as you make each hole. If you lean on the drill, the bottom of the slab can spald as you break through and give you a thinner measurement than you really have. Once you have drilled the holes, take a wire coat hanger and hook the end and test each hole for thickness. The aggregate (rock) in the concrete usually settles to the bottom of the slab so really try to measure the smooth portion of the hole and not the rock at the bottom for an accurate measurement.

You will be using wedge anchors for the installation. Most manufacturers send out the cheapest ones they can find with the lift. The newest and best anchor bolts, that can be used near cracks and edges of the slab are Hilti "TZ" anchors. http://files.buildsite.com/dbderived-f/hilti/derived_files/derived330778.pdf
Follow the manufacturer's instructions for anchor lengths and embedment depths for a minimum requirement. Thin floors can sometimes work with epoxy anchors because they do not require a setting length like expansion anchors and therefore can use the full thickness of the slab instead of only 3/4 of the slab.

A straight 2x4 and a 3' level will give you am idea on the floor slope. Since it sounds like your slab is close you will not have to do too much shimming, but you will have to shim and level the columns slightly to get them perfect. The best way to do this is with plastic horseshoe shaped washers. Don't worry to much about the floor slope as it is what it is, just get the lift level. Only a very dramatic slope will cause problems with adapter height on a level lift.

12" from the edge of slab is more than enough for the anchor bolts but it does sound a little tight for access walking around the lift.

Good Luck getting it installed!

 

[nehog]

I've a 10K Rotary 2 post in my garage. As to some of your questions:

1. Contact the lift manufacturer for their recommendations. Rotary was very good at making sure that things went well for me. Also (mine was new) they are good at being sure that everything needed was included with the kit, including the anchor bolts.

2. Level: Generally you'll just level with shims. Rotary included plastic shims with the lift (I was surprised they were plastic, but they're the experts). I never needed any as we made sure the floor was absolutely level and flat (two different things!) when we poured it.

3. Your 12" on each end (side?) is way too close. Personally I don't think that will work.

4. As others mention, concrete gets stronger as it ages. I doubt that it will be an issue, but flooring people have the ability to test it for you. Consider contacting one or two places and ask if they can do the testing. It may be a good investment.

5. Rotary specifies how to replace floor sections if the existing floor is not adequate for the job. Not that difficult, you cut out a section, and simply re-pour to the desired thickness.

Again, however, I don't think you can work with a 12 ft wide lift in a 14.5 ft wide bay with walls.

 

[rsanter]

you have some options. the previous answers given are all good ones, but I will give an alternative

check your concrete thickness and if it is not thick enough you have a couple of options.
1 cut 4 pieces out of the floor and pour new footings in the floor with anchor bolts for mounting the lift.

2 get 4 - 1/2'' thick steel plates that are 18''x18'' and install them between the floor and the lift on your existing slab. this will spread the load out to where the PSI loading should work even for a 3'' to 4'' thick floor

the floor does not have to be level, just the lift.
figure out the elevation change and install shims as needed to level the lift

bob

 

[nehog]

the floor does not have to be level, just the lift.
figure out the elevation change and install shims as needed to level the lift

bob

I'll stick in this: if the floor is not flat, you must shim up the posts (on a two post lift) to allow the arms to swing properly. Otherwise they can scrape on the floor (been there, done that!) when the lift is all the way down. Of course that doesn't apply to a four post lift.

Rotary does say in their installation, that you can replace sections of the floor if it is not up to specs. (In my case, we poured it specifically to meet the lift's specifications.)

 

[MarkyK]

Thank you every one. After measuring the concrete I found it to be to thin 3". But with the information you all have given me Plus the power of Google I am confident I will have the new slab in and the lift operational in a reasonable amount of time. Thank you again.

 

[nehog]

Thank you every one. After measuring the concrete I found it to be to thin 3". But with the information you all have given me Plus the power of Google I am confident I will have the new slab in and the lift operational in a reasonable amount of time. Thank you again.

You probably won't have to repour the entire floor, but just a section. If Mohawk can't supply you with the specifications, I can send you the ones that came with my Rotary lift. IIRC, it was about a 4x4 section that you'd replace with a certain depth of concrete.

 

[Snap50]

You can check the concrete strength in place; it's called a Windsor Probe test. A pointed stud is "shot" into the concrete using a powder actuated gun and then the portion left projecting from the concrete is measured and referenced to a chart to determine the approximate concrete strength.

You can core a hole to find the approximate thickness, but that doesn't tell you what you have a foot away.

It's a good plan to cut a portion of the floor out and replace it or install appropriately designed footings for the lift. Your life and vehicles are at risk. You are probably talking about a minimum load of delivered concrete, so you might as well pour a substantial thickness, not just 5" or 6". That way you can get substantial anchor bolt embedment and the strip can act as a footing. And absolutely install some rebar in both directions, both for strength and to control cracking.