MaxJax on shallow floor

[73 Mustang Bill]

I had my garage built almost two years ago, and knew that some day I'd get a MaxJax. I told the concrete guy that I needed at least 4 inches of depth, and would prefer 5. He said that he was giving me 5.5 inches. Stupid me, I trusted him without checking it before it was poured. I also asked for (and paid for) 3500 psi concrete.

I drilled my first hole for my new MaxJax and found out the depth is only 3.5 inches. The sumbitch lied to me. I wonder now if I even got my 3500 psi concrete, as I never saw the invoice from the concrete company.

I have an email into Dannmar to see if there is anything that can be done, but it's going to be a couple days (posted this on Saturday afternoon). Anyone else have this problem, and how did you solve it? I have a nice epoxy/polyurethane floor, and would hate to have to cut some pads and repour concrete.

Oh, and my concrete guy is OFF my Christmas card list.

 

[73 Mustang Bill]

And my saving grace might be that I'm at 109 inches, and I don't have to lift any tanks.

 

[mikeyr]

post your answer here when you find, I drilled my Maxjax holes today and found them between 3 3/4 (maybe 3 1/2+ hard to tell exactly) and 4 1/2, I was surprised at the variation expected it to be closer to all the same.

 

[73 Mustang Bill]

Just talked to Gabe. Since i"m not lifting massive vehicles (my heaviest car is about 3600 lbs), he thought that I'd be okay with just epoxying them in. He also mentioned that this is probably below code, so between the contractor, the concrete guy, and the inspector, maybe something will be done. I'm not sure that I like the possible options, since I have an epoxy/poly floor down, and any actions are going to involve ripping some or all of that up and redoing it.

 

[regguy1]

Just talked to Gabe. Since i"m not lifting massive vehicles (my heaviest car is about 3600 lbs), he thought that I'd be okay with just epoxying them in. He also mentioned that this is probably below code, so between the contractor, the concrete guy, and the inspector, maybe something will be done. I'm not sure that I like the possible options, since I have an epoxy/poly floor down, and any actions are going to involve ripping some or all of that up and redoing it.

If the specs were written in the contract and he didn't meet them you could have a case against him for the cost to bring your floor up to spec at his expense.

 

[73 Mustang Bill]

Yeah, I'm investigating that option. The plans call for 4 inches. I'm going out soon to drill another hole, more in the middle of the room. I hate the thought of having this fixed, because it will me removing everything in there, having them cut up two 4'x4' pads and repouring them, or possibly ripping out the entire floor and reporing it. Well, it would give me an opportunity to make the urethane/epoxy floor better.

I'll keep you posted.

 

[Cobra6]

I would just jackhammer out an area where the two posts will be sitting for the lift. You can get some exact specs, but you could go a foot larger all the way aroind the footprint of each post.

Or cut a large rectangle that will allow for the total area needed -

You can get the contractor to do the work to fix this and collect the difference in cash for what they didn't do on the pad and to redo the epoxy coat, but I wouldn't repour the whole thing.

 

[szyg6h]

Maybe a stupid question from me:
Is that a 2 post lift? ...or?
Ive wondered about how much concrete you need for a 2 post.

 

[73 Mustang Bill]

I talked to Gabe at Dannmar (he's great, by the way). He recommended 12 feet wide (the width of the car plus some), by 4 feet (longitudinally on the car), 12 inches deep. Since I want the option of being able to install the lift on the other side as well, we're talking 24 foot wide (side to side in the garage) by 4 feet. My garage is 26.67 feet wide inside, but have counters on one side that would be a pain to have to move, and metal shelves on the other side. Those might need to come down. The builder seems to be okay with this, although he hasn't talked to his concrete guy yet. I have to talk to Alpha Garage, the guys with the epoxy flooring to see what it's going to take to patch the floor there. I have a random blue color to the floor, so I'll have to do something so that it looks like it was done on purpose.

 

[73 Mustang Bill]

Maybe a stupid question from me:
Is that a 2 post lift? ...or?
Ive wondered about how much concrete you need for a 2 post.

It's for a MaxJax. It's not a question of being able to support a load, but being able to resist a bending moment. The bolts ont he outsid of the post are in tension, as the post is trying to tip inward. Without enough concrete thickness, the concrete could crack, or the anchors cold rip out of the floor. It might happen slowly, or it might happen quickly. It certainly would be stupid of me to continue the installation since I know there is a problem. I'll get it fixed properly, and not have to worry about it.

 

[szyg6h]

It's for a MaxJax. It's not a question of being able to support a load, but being able to resist a bending moment. The bolts ont he outsid of the post are in tension, as the post is trying to tip inward. Without enough concrete thickness, the concrete could crack, or the anchors cold rip out of the floor. It might happen slowly, or it might happen quickly. It certainly would be stupid of me to continue the installation since I know there is a problem. I'll get it fixed properly, and not have to worry about it.

Notice Mustang Bill, I was saying my question may be a stupid one, not yours- want to clarify that.
Also isn't there a fore/aft bending moment as well?
...and you are talking 2 post jack?

 

[73 Mustang Bill]

No, I understood what you meant. I don't think the fore/aft bending moment is anywhere near as much. Yeah, the MaxJax is a two-post lift. Go out to their web site, and look at the FAQ. They talk at length on the moments, and how strong the anchors are in the concrete (at 4 inches), etc.

 

[szyg6h]

No, I understood what you meant. I don't think the fore/aft bending moment is anywhere near as much. Yeah, the MaxJax is a two-post lift. Go out to their web site, and look at the FAQ. They talk at length on the moments, and how strong the anchors are in the concrete (at 4 inches), etc.

Good, happy that you understood!


Thanks for the MaxJax info- I'll go there next.

 

[TommyK]

Rather than replacing that much floor perhaps you could pour piers with rebar and drop in anchors.

 

[73 Mustang Bill]

The idea of piers was brought to the attention of Gabe at Dannmar. The 12x4x1 new pour is what he suggested. I don't like the drop-in anchor approach, because they have to be placed very precisely. If any of them shift even the slightest, it won't work and you are screwed. It seems that the epoxy is the way to go when setting the anchors because they are sctroner than just the wedge anchors, and the larger pour makes it one continuous reaction mass, which is less likely to shift.

 

[skamp]

You are doing the right thing. If there is a doubt it is not worth the risk. I am right at 4" on mine and not all of my anchors set as nice as I would like. I did fill the hold about 60% with expoxy before setting. I still have to mount the posts and tourque to 90 ft/lbs. If they dont rotate or pull up I am going to test with a light car and work my way up. If I have any doubt during my testing I will be cutting out the concrete and repouring. In my case I will be doing 4'x4' sections ~18" deep. I cannot do the whole length as I have post tension cables 4' apart so need to do 2 smaller pads. I am also going to use the expoxy anchors if I need to repour. Good luck on your repour.

Steve

 

[73 Mustang Bill]

Concrete guy called this morning, looked at it at 1:00, wants to cut it out tomorrow morning, possibly pour new concrete in the afternoon. I'll take pictures and post them, as well as get an estimate for that this would cost someone else to do, as I'm sure someone out there in TV land will have to pay to have it done at some point.

 

[regguy1]

Concrete guy called this morning, looked at it at 1:00, wants to cut it out tomorrow morning, possibly pour new concrete in the afternoon. I'll take pictures and post them, as well as get an estimate for that this would cost someone else to do, as I'm sure someone out there in TV land will have to pay to have it done at some point.

Is this the builder making it right at his expense?

 

[73 Mustang Bill]

He is. They came out this morning and ripped out a patch of concrete 21' by 4'. Gabe at Dannmar recommended 12'x4', but I want the ability to have a narroow set of posts, turn the center one around and have a wide set of posts, which is why I went to 21'. That way, the original pad still has a couple feet on each side to maintain the original integrity. They had 20 places where the drilled into the exisiting slab (two on each end, the rest on the long segments) and epoxied in steel rebar sticking out 12". They poured 3500 psi concrete with extra hardener this afternoon, and are just slicking it off now. The guy that slicked it off with the machine originally is out there slicking this, to try to get the same finish (good or bad), so that the stain will hopefully take in the same manner.

I'm going to try to stain it as original, but if that fails, I'll do something like a Start/Finish line, or embed car emblems in there. They scratched and chipped some of the floor to the door, so I'll have to investigate fixing that as well (at their cost as well). It gives me an excuse to fix some of the problems that I caused during installation, and that I've caused over 2 years of use.

I was bragging to my friends this mornign that I was having a lap pool installed in my garage. I don't think anyone believed me.

 

[skamp]

Wow, that was quick. That is great that they did the right thing and made this right. I would for sure go with the epoxy anchors after this cures. Congrats!

Steve

 

[73 Mustang Bill]

Epoxy anchors are already on order, and will be here tomorrow (even though I can't use them for 30 days). Also note that I didn't call and scream at the builder. Since it was less than 2 years from new, I didn't have to. He realized his mistake, and was willing to correct it. I'll bet the total bill on this one reaches $1500 by the time I finish the floor, so maybe there is a lesson to be learned there. I'd bet that they poured it a little shallow to save $100 on 1+ yard of concrete, and it bit them. I don't think I would have had any problem proving that they didn't order enough concrete to pour it 4 inches thick, so obviously a mistake or intentional on their part. They stood up and fixed it though.

 

[skamp]

Epoxy anchors are already on order, and will be here tomorrow (even though I can't use them for 30 days). Also note that I didn't call and scream at the builder. Since it was less than 2 years from new, I didn't have to. He realized his mistake, and was willing to correct it. I'll bet the total bill on this one reaches $1500 by the time I finish the floor, so maybe there is a lesson to be learned there. I'd bet that they poured it a little shallow to save $100 on 1+ yard of concrete, and it bit them. I don't think I would have had any problem proving that they didn't order enough concrete to pour it 4 inches thick, so obviously a mistake or intentional on their part. They stood up and fixed it though.

It is nice to hear that a contractor did not try to worm out of this. I am going to test my MaxJax this weekend so I will know if I am in for a similar cut and repour operation.

Steve

 

[wachuko]

It is nice to hear that a contractor did not try to worm out of this...
Steve

+1

 

[73 Mustang Bill]

Before the concrete guys came in to remove my concrete, the wife and I humg some plastic sheeting from floor to ceiling, and taped EVERY inch of it. One area was covered twice with the same method. After it was all said and done, I took the plastic down, hoping for nice clean workbenches, etc. WRONG. There was dust EVERYWHERE. I've already spent a couple hours cleaning it up, and will have to spend many more. It got on top the workbench and tool boxes, and inside of cabinets and drawers. When you wipe it off, it just generates mud, so you have to clean everything 2-4 times. I don't know what the right answer is.

 

[Cobra6]

That type of dust is nasty - can't really even vacuum it up.

It is "heavy" dust, so you have to touch every square inch of it to get it up. You just about have to use at least a damp or wet cloth to keep from scratching everything, and yes it turns to mud.

In my experience, it takes two times cleaning to get it off.

 

[In My Garage]

I drilled my first hole for my new MaxJax and found out the depth is only 3.5 inches.

Well my concrete floor is about 4 inches, more or less, depending where you measure.

As far as I'm concerned, I would not trust my MaxJax install unless I had at least 6 inches, and preferably 8 inches of the type of concrete used in industrial shops (appears to be smooth and high density). Unfortunately, when I had the house built, I never expected to install a lift.

So I dug out a 3 foot by 12 foot trench that will be roughly 16 inches deep and reinforced with re-bar that will hook into these stainless steel mounts that I made. The MaxJax will sit atop those plates and bolt into the rods which are now threaded.

Additional round stainless steel cross bars have since been welded to the bottom of the vertical bars for additional anchoring. This ain't going nowhere!

 

[78Bird]

I like overkill, but damn man...


you could lift the house with that.

 

[In My Garage]

I told the concrete guy that I needed at least 4 inches of depth, and would prefer 5. He said that he was giving me 5.5 inches. Stupid me, I trusted him without checking it before it was poured. I also asked for (and paid for) 3500 psi concrete.

I drilled my first hole for my new MaxJax and found out the depth is only 3.5 inches. The sumbitch lied to me.

Well, if you want the job done right, you have to do it yourself. My motto: trust no one (especially where money is involved), which is why I never hire any trades and do everything myself.

Although the specs for my garage floor are 4 inches, it is thinner in various areas. But it does what it was designed to do...park cars on it.

I'm just in the tail end of my MaxJax installation and all I can say is I am glad I did not assume my floor is thick enough. I was not so much concerned about the load bearing capabilities, but more concerned about the effectiveness of the supplied Wej-It anchors in questionable concrete.

I decided to go all out, after all, I'm the one going to be under my car. I fabricated my own anchoring system and set it in a rebar reinforced 3' x 12' x 14" thick concrete slab.

The original 4 inch concrete slab in my garage. Quite a bit thinner in places.

My anchoring system. Not in place yet: there are two more lengths of rebar running at the edges of the mount.

Personally, if I used the supplied anchors, I would not go with a slab less than a true 6 inches. After all, Wej-It calls for a minimum 5 inch drilled hole when using the PD-58 anchor and Dannmar clearly shows a diagram calling for an approximate 5 1/2 inch hole.

 

[NUTTSGT]

My anchoring system. Not in place yet: there are two more lengths of rebar running at the edges of the mount.

Is that being set in place and then the concrete poured or set in the concrete after being poured ?

 

[In My Garage]

Is that being set in place and then the concrete poured or set in the concrete after being poured ?

Both mounts were in position as the concrete was poured slowly into the excavated area. The leveling bolts were marked on the existing concrete floor just in case the mounts were accidentally bumped into. Also, it enabled slight lifting and resetting during the pour.

A concrete ******** was used to take care of any air pockets.

When the concrete reached the bottom of the existing concrete floor, I made sure there were no air cavities under it. Same for under the plates of the mounts. At that point, I also pulled up the eight 4 foot rebars that were across the cut slab so that they were under the existing concrete floor (see pic below).

That was a week ago. I have another 3-week wait for full strength and I am keeping burlap that is damp/wet on top of the set concrete. The temperatures here are good for slow curing.

Now that the concrete has set for a week, I ran a black nylon fishing line along the scribed lines atop the center of the plates...they line up 100% and the plates are level on both axis.

 

[pauls340]

Here's what I did. There is a product available called Vapor Lock by SPG. This product uses water IN the concrete to change it to additional CSH (calcium silicate hydrate gel), the stuff that makes concrete stronger...raises the psi level. I'm thinking my concrete guy shorted me also but as a cheap additional helper, I used Vapor Lock. As long as your concrete has not been sealed with anything, really wet the floor with water, it soaks in and then spray two coats of VL. VL chases the water as deep as possible and changes it to CSH. My garage floor has ZERO moisture anywhere on it. Checkit out and good luck.

 

[regguy1]

That lift isn't going anywhere......and if there's a nuclear war it should still be standing