2 post lift near shrink cracks??
 

My shop I had built is getting a lot of shrink cracks including right where I had always planned to install my lift. I know lots of steel was used and its thick enough. Anyone mounted a 2 post on or near a crack and had good or bad results?

Re: 2 post lift near shrink cracks??
 

That would depend on what a lot is. If they are long cracks that don't intersect it may not be an issue. If they are short and intersect it may be a problem. The amount of steel doesn't do any good if the mix was wrong. The floor should have been sawn to releave stresses and head off cracks.

You may have to re-pour the section where you want the lift. Get a Structural engineer to guide you on the concrete cracks.

I have seen the results of a poorly installed lift and it wasn't pretty. It snapped off the floor and a man lost his foot because of it. He was pinned and there wasn't anything we could do for him until heavy rescue got there.

Re: 2 post lift near shrink cracks??
 

The tape follows next to where the cracks are. The square on the ground is where I had planned to put one of the legs of the lift. It makes me sick just thinking about it. :barf: When my contractor was still taking my calls all I got was concrete cracks don't worry about it.

http://i936.photobucket.com/albums/a...g?t=1305598313

http://i936.photobucket.com/albums/a...g?t=1305598313

http://i936.photobucket.com/albums/a...g?t=1305598313

http://i936.photobucket.com/albums/a...g?t=1305598313

http://i936.photobucket.com/albums/a...g?t=1305598313

Re: 2 post lift near shrink cracks??
 

Thats a lot of cracks. Your floor has issues. I personally wouldnt put a car on a lift and stand under it on that floor. I have seen a lift rip out of the floor due to bad concrete and its scary.

Re: 2 post lift near shrink cracks??
 

I don't know a lot about structural things but I have a two
post and a crack-free old floor. My building leaks like a sieve
but the floor is unaffected nor is the hoist.

I would personally do the following:
1. Talk to your contractor (even if you have to visit in person) and have him fix your floor.

Did he know you were putting in a lift? if so...

2. If you need your lift now, cut out patches, set deep footings for the hoist and bill the contractor.
When he rebuilds your floor, make him work around your hoist.

Good luck and keep us posted.

Re: 2 post lift near shrink cracks??
 

You need a foundation expert for that floor. That is a lot of cracks for a fairly new floor. If Dallas is anything like Houston then this dry spell isn't helping

Re: 2 post lift near shrink cracks??
 

IMO, have someone come and take a look at it. In your pics I don't see any control joints or expansion joints (maybe the south is different from the north in that aspect?) , for all we know the slab is poured over mud.
It does appear you've got too much invested NOT to get what you paid for.

Re: 2 post lift near shrink cracks??
 

What's the slab sitting on? Sand, gravel, rock? Mine sits atop 20ft of blasted ledge, I had 1 crack in my 6 inch thick floor, I put my lift in, bolted it to the floor, and I had to bolt shallow as I have a heated floor. Holds my 07 cc duramax about half way up. I'm to chicken to go higher. Lol

But id have the guy that poured it back to take a look, that's slot of cracks.
Posted via Mobile Device

Re: 2 post lift near shrink cracks??
 

It all sounds great in a perfect world but I am dealing with a small company and he is constanty out of state on other projects and can't be reached. He knew there would be a lift and the floor is 6" and has lots of rebar. If I knew what I knew now I would have gone about this 100% different but I didn't so now I have to lay in the bed I made.

When I started this and was looking for a contractor none of the big well known companies wanted to deal with a small project like mine or was a year or longer wait. I started asking around the smaller guys and interviewed several. I felt the best (at the time) about who I went with but its been a nightmare since. It still took 4 months to get started and concrete and steel when up and my materials went up by 1/3. I was way over budget because of this but once finally started it went up fast. At the time there was a lot of small details I was not happy with but I convinced myself I was being to picky and most people don't have the same standards as I do. I was just happy to finally have a place to work again. The job was completed and then the real fun started. About 2 weeks later we had our first rain. It was just a light mist but I got home a had I a little water in the floor in the corner. I called the contractor and he cam right out said sorry my guys forgot a few screws at the top of that wall. Its fixed now. All is well..............NOT!!

A few weeks later we had a real rain and storm. I got home that night and the over side of the shop was a lake and every time it rained again the same thing but I could not figure where it was coming in. One night a storm was coming so 1:00 am with flashlight in hand I was going to find it. I did and it was coming from the top of the walls. After some more investigation The way they did the gutters and flashing was 100% wrong. All I got was excuses and blaming the sub contractor. After a month he got the sub out there to "fix" it. I got home that night excited to see the repairs only to find nothing changed. After 3 months of constant calls and near daily emails I finally recieved and refund check for enough money requested for materials so I can fix the leaks myself.

In the mean time the concrete started the cracking and all I get is concrete cracks don't worry about it. I have talked to a few people for legal advise and have pretty much been told after I spend the money even if I win the chances are high they will fold the business and start up under another name. I am then stuck with the legal bills. I am just so ready to put this whole learning experience behind me and play with cars again.

The cracks started long before it got dry and hot and seems to have not got any worse over the last several months
in this heat.

At the time when I still trusted everything he said he told me they are not needed.

He has get to come back out but I have send multiple pictures close up and the ones you see here. All I get it it normal don't worry about it. Whats funny now is everywhere I go I see cracks in concrete and they are everywhere. From the mall parking lot to bridge overpasses. My eyes just go to them.

Its built partly over a old stable 24 x 36 shop slab that had been there 10 years and sand. I had 4' x 4' x 10" areas poured for the old shop for the lift and it worked fine but I did not want to have to do that with the new shop but I may have to.

Re: 2 post lift near shrink cracks??
 

I like the idea of an expert opinion. Cracks big? hairline?
If the slab is flat maybe just cut out a section a little bigger than your rack.
If you do that be sure they(or you) install epoxied rebar to tie into the old slab.

Your siding? What is it? has a very interesting (cool) look to it.
I spy a Cutlass. Are you the same gearheads78 moderator on ClassicOlds?

Re: 2 post lift near shrink cracks??
 

Yup...Thats me. Kinda been tired of the Oldsmobile or No-mobile vibe around there lately.

The cracks ar not big but not small. They range from hairline to 1/8" in the widest spots.

The walls and roof are all covered in closed cell spray foam insulation and coated white. I am very happy with that part of the building. (someone else did that)

Re: 2 post lift near shrink cracks??
 

CO does get a bit dramatic at times :lol: Still my fav Olds site.
1/8th" seems pretty wide on the cracks. Maybe the county could point you in the right direction as to whom has architectural engineering background that can inpect your slab?

Re: 2 post lift near shrink cracks??
 

All concrete will shrink (and crack) when it cures. Most contractors will put in control joints every 12 ft or so in a slab. That way it will control where the cracks will be. In your case not under the lift posts. They usually saw-cut the slab about ½ inch deep for the control joints or imbed a plastic strip in the concrete when they pour it. Too late now, though. I wouldn’t worry too much about it, but would try to move the lift posts as far away from the crack as you can. Also try to find a lift that has as large a foot on the post as possible. If you’re really worried about it, you could cut out the area where your posts will go and pour a nice big footing, but I wouldn’t mess with it. You might check with the manufacturer of the hoist and see what they recommend.

Re: 2 post lift near shrink cracks??
 

dmarty is on the right track. The cracks are only in the surface, a result of concrete expanding and contracting. It used to be standard for a floor to crack, which is why they cut the surface now.

Personally, I am not a fan of two post lifts, but they have their advantages. Big thing is to balance the load. It's the unbalanced load that tears the bolts out of the floor. With a good mix and the right steel in a 6" slab you won't have any problems. I would stay away from the cracks, if possible, but wouldn't be too concerned if there was a crack between the posts.

Re: 2 post lift near shrink cracks??
 

The only sure way to tell if its the skin cracking when it dried would be to rent a core drill and cut a core over the crack pull it up and see how deep it goes. You can them make your decision and just plug the hole. A 2" core would be more than enough to see whats up. It should only take about an 1/2 hour to drill and pull the core. Yo will also know exactly how thick your floor is.

Re: 2 post lift near shrink cracks??
 

I would assume the cracks go all or most of the way through if it is due to shrinking right? Would the bottom shrink less tan the top?

I do know the thickness is 5" plus all over. I messured the depth of the set ups the morning before they poured.

Re: 2 post lift near shrink cracks??
 

If they don't water the top enough when they float it and while its drying it can get surface cracks in the top kind of like a skin that cracks, If its only goes down less than 1/2" then you most likely don't have to worry about it. If it goes 3-4 inches then you have a structural issue and I would not put a lift in without re-pouring the section under the lift area.

Re: 2 post lift near shrink cracks??
 

our rotary lifts have cracks in the floor around the base. you should have at least 3000 psi concrete I would cut out a 4 foot by 4 foot section pore it 6 inches thick and "key" it into the existing slab. you can drill into the existing slab and epoxy rebar in. thats what i would do. I am a civil engineer that would rather build cars:lol: cinch anchor the bolts in at least 4inches or you can buy the epoxy test tubes that have aggagrate in them and insert them in the drilled holes but they run around 30.00 each. crank the bolt torque down to 145-50 foot pounds. you will be good to go. git er done:lol:
you can rent the saw and do it yourself. hard part would be getting the small order of concrete you may have to mix yourself but around here you can buy it in small orders.