Garage floor concerns for MaxJax install

[c4cruiser]

I just joined the site but I have been lurking for some time. I've been reading a number of threads regarding the MaxJax installs that members have done and there are some tremendous tips

The problem I have with my MaxJax install is that the floor area for one of the posts is crack-free but the other area has a number of hairline cracks and one crack that looks to be 1/32 to 1/16 wide and is within 3" of one of the anchor holes locations. I tried other positions and spacing, but there really isn't any way to avoid the cracks in that one area.

So my question is how much of an area where the cracks are located should be removed and re-poured? The floor is spec'd at 4" depth using a 3000psi mix. Also the floor is 20 years old. Can a re-poured area be tied in with rebar?

 

[skamp]

I just joined the site but I have been lurking for some time. I've been reading a number of threads regarding the MaxJax installs that members have done and there are some tremendous tips

The problem I have with my MaxJax install is that the floor area for one of the posts is crack-free but the other area has a number of hairline cracks and one crack that looks to be 1/32 to 1/16 wide and is within 3" of one of the anchor holes locations. I tried other positions and spacing, but there really isn't any way to avoid the cracks in that one area.

So my question is how much of an area where the cracks are located should be removed and re-poured? The floor is spec'd at 4" depth using a 3000psi mix. Also the floor is 20 years old. Can a re-poured area be tied in with rebar?

You should really talk to Dannmar about installing near the cracks. The install guide states you should be 12" away from any crack. There are multiple threads on people who cut a section and repoured the concrete. There are also a bunch of posts on the pros and cons on tying into the existing floor vs leaving it floating. The biggest con being if the new section sinks a little it can crack the slab around it. Personally if I had any concerns I would cut out the section and repour it. It is just not worth the risk when you are under a lifted car or truck.

If you do the work yourself it would be maybe $500.00 at most to rent the concrete saw, dig the 6-12" deep pad and get the concrete delivered. I think most people think a 4'x'4x12" pad is way to go. Some have even spanned the two pads. I hope this helps.

Steve

 

[UPSHIFT]

I just joined the site but I have been lurking for some time. I've been reading a number of threads regarding the MaxJax installs that members have done and there are some tremendous tips

The problem I have with my MaxJax install is that the floor area for one of the posts is crack-free but the other area has a number of hairline cracks and one crack that looks to be 1/32 to 1/16 wide and is within 3" of one of the anchor holes locations. I tried other positions and spacing, but there really isn't any way to avoid the cracks in that one area.

So my question is how much of an area where the cracks are located should be removed and re-poured? The floor is spec'd at 4" depth using a 3000psi mix. Also the floor is 20 years old. Can a re-poured area be tied in with rebar?

C4cruiser,

I would just try and keep the back 3 holes 3" from the cracks and as long as the anchors are set and not pulling up when you lift a car it should not be an issue. The most important deal is to be sure the bolts are 6" from any edge of concrete. Hope this helps.

Gabe
Dannmar 877-432-6627 X 126

 

[Jvvmusme]

I would not worry about the cracks if your mother in law is the one who is going to be under the car... Otherwise safety is always first. I would follow danmars advice + make a new concrete pad as big as you can afford