Mud Jack or Polyurethane Foam for lifting garage slab?

[SteveL]

I have a 50+ year old garage slab floor that has developed a crack that runs parralel with the overhead door and is now sinking which causes water to run back in to the garage and pool right where the wife gets in an out of her car. Pretty sure my only options are to tear out the old slab and re pour or to "mud jack" back to level. I've had one guy come out to look at it so far and he suggested using a polyurethane foam instead of the traditional mud/concrete slurry. Anyone have any experience with the process and can share some wisdom? Trying to keep the cost down but also want to make sure that it's done the right way. Once the repair is done, the plan is to remove the old epoxy finish and apply a new coating over it and the new addition that was added about 8 years ago.

I'm assuming that the new addition is what caused the cracks as we removed the old exterior brick wall and poured the new slab up against the old.

Any help would be greatly appreciated.

 

[duneslider]

My dad has had his driveway and covered patio mud jacked. It worked good at first but I don't know what has happened but in the 8 years since he did it they have sunk again. Not sure if this is normal or not.

Mud jacking was way less expensive than replacement though so he still says he is happy and may even jack it again since the concrete is in otherwise great shape.

Never heard of jacking with foam. Sound interesting.

 

[Shea]

Using polyurethane foam is more expensive, but it generally lasts much longer. Water intrusion can cause the mud jacking slurry to break down and deteriorate causing the slab to sink again. The foam won't do this.

It also requires smaller holes to be drilled into the concrete compared to the much larger ones for mud jacking. I believe they drill less holes as well.

 

[chase237]

I just had it done in one are of my garage. In my case the garage is only 8 yrs old and I can see evidence of a previous mud jack so it's clearly a problem with a poorly compacted base and more than likely water infiltration. We've taken care of the water problem so hopefully the poly foam fix will be the end of it.

With that being said, the finished product is just a marginal fix. It came out close, it will never be perfect short of a complete tear out and re-pour.

My opinion is that the foam injection sites are where you get most of the lift due to the expansion rate. I could be wrong, I'm not an engineer. It's also my opinion that because of this kind of pinpoint lift the quality of work really relies on the skill of the guy on the nozzle and the reliability of the equipment. There were a couple times the nozzle stuck open and caused a bit of a panic by the dude on the nozzle. Nothing big just an extra second or two of foam. They only do 3 second bursts then watch for results, then another burst as they start to lift, move to the next site, etc. etc.

The slurry from mudjacking flows to the voids more uniformly until the whole void is filled then you get lift. I wonder about the comparison if it's measured in PSI and you could actually measure in small square foot areas. They do drill more holes for injection sites than mudjacking. The holes are hardly noticeable compared to the larger mudjacking holes they drilled and repaired.

My lift also created another crack which was expected and will be easy to fix with the sand and epoxy treatment. Like I said, it's not perfect but it's a ton better than it was.

I think I have some pics in the link in my sig line.

 

[SteveL]

Will likely go with the polyurethane and hopefully it will end up close. Plan on having the old finish ground off before re coating so they should be able to level any minor difference.

Thanks for the replies.

 

[EvanTX4]

Hi Steve,

Hoping to revive an old thread...

How'd it go? I'm currently pondering the 'ole mud vs poly question myself. My area isn't quite as large your's though. It's basically a sidewalk, or a "cart-path," that goes from the back of my garage, along the side of the house, and out to my backyard/old golf course. From what I read, it sounds like the more serious the repair the more likely you should go Foam. I'm somewhere in the middle - it's just a sidewalk, but it does abut against the house's foundation slab as it runs along the house... Any insight would be great as the difference in price is almost double.

Thanks,

 

[Itsjustdirt]

what are you guys paying for this process? Are we talking 1 thousand or 50 thousand? Just looking for a ballpark idea.

 

[EvanTX4]

$700 mud / $1500 - foam. I'm in the south part of Houston for perspective...

 

[Itsjustdirt]

WOW! Way cheaper than I thought. Is this only for outdoor slabs or can it be done on house foundations as well?

 

[EvanTX4]

I've recently read posts (I believe some on here) where people are using the Foam for foundations. But, I don't think its apples to apples - there may be two different machines for the different applications... I just can't imagine that the injector nozzle I've seen used for the outdoor slabs has enough pressure to work properly for a foundation. Bottom line I guess is that I bet its more expensive for foundation work - whether its a bigger machine or more holes/foam. Hope that helps....