Max Jax install and concrete thickness issue

[jaym3smg]

Hey all,

I finally installed (or at least tried to install) a Max Jax lift. I know a few people here have them, and I need some help with an issue.

Basically on each post you have three 'rear' bolts and two center bolts which are closest to the arms. I managed to get the wej-it bolts in for the rear three on each post with no issue, and they are SOLID. The center ones, different story.

The concrete is 4700PSI reinforced and 4" at least throughout, according to the builder. Upon drilling however I found that this is not necessarily the case everywhere. Again, all the rear bolts are fine but the center bolts are not. Only one center bolt caught properly into 4" concrete. The other 3 holes are 2.75-3.5" deep and that's it. I have no idea why, but I suspect as you get closer to the center of the garage the concrete might have gotten shallow for some reason.

So what should I do to solve this? I was thinking of dropping these in:

http://www.grainger.com/Grainger/RE...?cm_mmc=PJX-_-GraingerBrand-_-43737-_-Generic

They would fit the already drilled hole and the tension ratings seem to be way more than I need for this lift. Would these work fine for what I am looking to do?

The other alternative is to carve out a chunk of the floor and repour, but I don't want to do that if I don't have to... at least not right now. Next year I would, and probably will regardless of my solution here.

In the meantime I am going to call the builder, as 4" minimum is building code so they haven't met code. I might be able to get something out of them, who knows.

So would the drop in anchors above work? Or am I looking at a rip and repour?

Thanks in advance!

 

[pattenp]

I'd cut out and re-pour concrete. I wouldn't trust any anchor in concrete that's 2.75 to 3.5 inches thick.

 

[JJThrasher]

Did you pay to have the pour done? If so did you specify the 4"? Sounds like you need to go yell at your contractor.

 

[jaym3smg]

I'd cut out and re-pour concrete. I wouldn't trust any anchor in concrete that's 2.75 to 3.5 inches thick.

Well that's the end plan I think... but I don't see any reason the anchors I posted wouldn't do the job I need them to do. Given their listed strength, they should be about 7x more than necessary.

Did you pay to have the pour done? If so did you specify the 4"? Sounds like you need to go yell at your contractor.

It's a builder home, but building code states a minimum PSI of 4500 and a minimum thickness of I believe 4". I am going to verify this Monday and if I find the builder has violated code, we'll be having a little chat

 

[dmeadow]

Check out the specifications on the MaxJax website. IIRC, the engineering and tolerances were done using only the "back" anchors. If so, I'd epoxy in the center ones and enjoy your new lift.

 

[jaym3smg]

Check out the specifications on the MaxJax website. IIRC, the engineering and tolerances were done using only the "back" anchors. If so, I'd epoxy in the center ones and enjoy your new lift.

Indeed, I checked the site, the three back bolts seem to take the most punishment.

I don't like the idea of just relying on epoxy for a 3" hole with the wej-it though, so I am thinking of picking up those Red Head drop anchors for the center bolts and epoxying them in. People here seem to like the Red Head stuff...

 

[70runner]

I'm in the same boat, related thread not far from yours. 7K lift, akin to a heavy duty Maxjax, on a 3.5" non reinforced slab. I posed my situation to several lift install companies. The gist of the feedback was two options, both cut and repour: (1) 4x16 pad, 8" deep if the job needs a permit/seismic checkoff (CA); (2) non-permit: 4x4 pad, 12" depth, pinned and/or doweled to the existing lab, with rebar.

The lift manufacturer specified 3x3, 18" pads. I ended up doing 4x4 pads, 18" deep with 2-3" undercut of current slab. Per feedback I got here I plan a free standing rebar cage, 2 matts, not doweled to the slab. Plan to use 3/4" Wej-it epoxy anchors (7" long). Overkill, perhaps, but peace of mind when lifting 2-3 tons overhead. More overkill, I plan to fab an overhead brace using 2" square, .188" wall steel tube.

I wouldn't go near ANY fastener for a lift on a 3.5-4" pad, but that's just me.

 

[In My Garage]

The back anchors take care of all inward moments.

The ones on the sides are for fore and aft moments should your car not be centered about the C of G.

I didn't piss around with the concrete that I had and poured a new section of slab. Either you trust what you have now, or you don't. I don't see the logic in using the lift now and doing it right in a year as you mentioned.

 

[jaym3smg]

Thanks for the feedback so far, all.

I'm in the same boat, related thread not far from yours. 7K lift, akin to a heavy duty Maxjax, on a 3.5" non reinforced slab. I posed my situation to several lift install companies. The gist of the feedback was two options, both cut and repour: (1) 4x16 pad, 8" deep if the job needs a permit/seismic checkoff (CA); (2) non-permit: 4x4 pad, 12" depth, pinned and/or doweled to the existing lab, with rebar.

The lift manufacturer specified 3x3, 18" pads. I ended up doing 4x4 pads, 18" deep with 2-3" undercut of current slab. Per feedback I got here I plan a free standing rebar cage, 2 matts, not doweled to the slab. Plan to use 3/4" Wej-it epoxy anchors (7" long). Overkill, perhaps, but peace of mind when lifting 2-3 tons overhead. More overkill, I plan to fab an overhead brace using 2" square, .188" wall steel tube.

I wouldn't go near ANY fastener for a lift on a 3.5-4" pad, but that's just me.

Sounds like I am starting with a bit better setup.. most spots are 4.5" and it is reinforced. It's just those center bolts that are giving me issues and I think I have a solution for that.

Do you mind telling me how much you paid for the concrete to be cut and repoured? I am trying to get a ballpark. As I might want to toss the lift in another garage bay (I have a 3 car) I am thinking of tearing up an entire strip of the floor and having it repoured so I have the option. I'll have to look at permits as well to see if I need one.

The back anchors take care of all inward moments.

The ones on the sides are for fore and aft moments should your car not be centered about the C of G.

I didn't piss around with the concrete that I had and poured a new section of slab. Either you trust what you have now, or you don't. I don't see the logic in using the lift now and doing it right in a year as you mentioned.

Ah ok that makes sense. Well I suppose the logic from my perspective is that I am putting in the Red Head anchors which would be more than enough for what I am lifting and I wouldn't run into any issues. This time of year the car is at the track a lot and I want to be able to use it for all the wheel and brake work I have to do. Since it should be more than fine with what I am using, I see no reason to not use it.

Then, I am thinking even in a few months or so when track season is over for me, I will have the concrete cut and repoured and can then over-engineer it with epoxy anchors, etc. Plus by then I will have some answers with respect to the building codes. I probably won't wait until next year, I don't really have to (or want to). I'd have to talk to the contractors to see what temps need to be to pour concrete. I imagine October or late Sept I'd still be fine.

 

[In My Garage]

I'd have to talk to the contractors to see what temps need to be to pour concrete. I imagine October or late Sept I'd still be fine.

I poured October 19th last year and could have anytime in November.

After the concrete was solid, I laid burlap over the poured section and kept it damp for weeks. My reinforced concrete slab is 3' x 12' x 14" thick.

I went really overboard with my MaxJax install, but I can sleep under my car without needing to leave one eye open.

 

[jaym3smg]

I poured October 19th last year and could have anytime in November.

After the concrete was solid, I laid burlap over the poured section and kept it damp for weeks. My reinforced concrete slab is 3' x 12' x 14" thick.

I went really overboard with my MaxJax install, but I can sleep under my car without needing to leave one eye open.

Yes, you did I saw your install in a few other posts. I like what you did, a lot actually, but I am probably good with epoxy anchors. I have no metal cutting or welding skills.

I may do a 4' x 12' by 12"...

 

[70runner]

Do you mind telling me how much you paid for the concrete to be cut and repoured? I am trying to get a ballpark. As I might want to toss the lift in another garage bay (I have a 3 car) I am thinking of tearing up an entire strip of the floor and having it repoured so I have the option. I'll have to look at permits as well to see if I need one.

My daughters boyfriend and I rented a concrete saw at HD, about $100, and did the cuts. Then we broke up the concrete with my trusty Harbor Freight demo hammer, loaded concrete and dirt into my Kubota front loader and moved it to inconspicuous area of property (10 acres). So $100 total for me so far. Probably about 2-3hrs work for typical concrete crew (took us about 5hrs).

Gonna repour using concrete rental trailer with motorized drum, about 1yd per pad, about $300 total.

 

[Mystic_Cobra]

I am looking at a lift for my garage as well. According to the codes (2006 IRC and 2009 IRC), garage slab minimum is 3.5" and 2500 psi. Based on that, I would assume that 90%+ of garage floors out there are NOT sufficient for a maxjax or other "relatively small" lift. I'm leaning towards the 9000 lbs Bendpak. I drilled a pilot hole in my floor and broke through at 3.5". Unless you have your slab poured specifically for this, I would assume nearly everyone has to repour. Am I wrong?

I'm getting ready to epoxy coat my floor and want to do this beforehand. Now I'm considering pouring one large (~12 ft) pad vs two small (~3 ft) pads? Is two necessary? I'll be doing the installation (of everything).

 

[pmiranda]

I would cut and re-pour. Consider that the area of concrete the "good" anchors live in is not very big if you only have a couple inches of concrete on the other side of the post. Those good anchors might hold well enough to tear out a chunk of your weak slab.
It's a fact of 21st century life that things are usually only built to the bare minimum requirements... if you're lucky :-(

 

[BABCO]

As a Canadian Dannmar dealer and installer, we recommend a good 2 part epoxy to be used with the anchors on MaxJax. I believe Dannmar sell it or you can get from the local Fastenal store or similar. The epoxy is stronger than the cement and will really hold the anchors. You still need the correct thickness and PSI.
I drilled a hole in my patio and used the epoxy to secure a eye bolt and locked my BBQ to the eye bolt. You would need a jack hammer to get the eye bolt out.

 

[Dolfan]

I had a similar situation with some of the original anchors but my concrete was deep enough. You can see the epoxy process and the anchors in this thread that I got from Dannmar.

http://garagejournal.com/forum/showthread.php?t=75488

I would be inclined to pour a new section to be certain, you don't want to risk it.

 

[dmeadow]

As a Canadian Dannmar dealer and installer, we recommend a good 2 part epoxy to be used with the anchors on MaxJax. I believe Dannmar sell it or you can get from the local Fastenal store or similar. The epoxy is stronger than the cement and will really hold the anchors. You still need the correct thickness and PSI.
I drilled a hole in my patio and used the epoxy to secure a eye bolt and locked my BBQ to the eye bolt. You would need a jack hammer to get the eye bolt out.

Having just done this, I would caution anyone using the epoxy that comes in the Dannmar kit to make sure they are ready to roll as soon as they open the epoxy. The stuff they supply has a working time of 6 minutes and a set up time of 30 minutes. You read right, 6 minutes! You have to cut the mixing tube at its largest opening, dump it in the holes as fast as possible, and bang in all the anchors in just a few minutes or you are basically screwed.

I was only able to do a few anchors with a tube of that stuff (it hardens in the mixing tube in less than 6 minutes), so I bought a Simpson product that has a 30 minute working time and a 16 hour set time.

You also need a really good caulking gun. I went ahead and bought a Simpson epoxy gun for around $23 at HD. A cheap, chicom caulking gun just won't squeeze out the heavy epoxy, especially not quickly enough for the fast setting stuff.

 

[torquepower85]

i would just get the epoxy anchors, i have never seen anyone complain about their maxjax uprooting and thats a pretty good testimonial

a lot of people go with the standard wej-it anchor bolt kit though too. it really is about the concrete in the long run, a lot of the anchors for lifts are overkill and rely heavily on the concrete.