Concrete doesn't crack - Printable Version
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Concrete doesn't crack - eaadams - 11-01-2012 03:34 PM
Slab tested at 75% and is 3 years old. Concrete Contractor is repairing with Sikadur 32
I wanted them to use Roadware, Sikadur 35, or Ardifix. The Sikadur 32 has already become concave and they are adding more today. I really wish this customer would SLU the floor but they want us to go over it...
RE: Concrete doesn't crack - CCR - 11-20-2012 02:47 PM
OMG. Gym floor on sleepers going in?
RE: Concrete doesn't crack - CC Solutions - 11-20-2012 03:10 PM
Why has the Sikadur gone concave? Was it not filled to capacity and shaved first? Either that or the floor is cracking that quickly that the joints have widened!
Probably the first explanation....
What a nasty looking floor. The cracks are indicative of a really poor substrate beneath it. That looks like long term trouble.
RE: Concrete doesn't crack - CCR - 11-20-2012 03:56 PM
Good call. Probably best to run from this one.
RE: Concrete doesn't crack - eaadams - 12-22-2012 12:05 PM
I will get pictures but I have to say I am impressed with the Sika product. The contractor came back and re-filled then came back and hand ground flat all the joints. I talked with him, he charged them less than $4000 to do all that crack repair and grinding. I'll certainly be using him for work in the future. All our normal floor prep guys wanted $15-30,000 and would only quote with a full SLU. It is interesting, few people do this sort of grinding in California. I really think there is a business opportunity there. SLU is just SO expensive, perhaps there is an untapped market for true tradesmen who can deal with these surfaces. I need to figure out who else can do that sort of work. I think I might talk with the grinding reps at world of concrete and ask who their best California customers are. Perhaps that is how I find the grinding equipment & people who can do this level of work.
We were able to install sheet vinyl on top without any show through of the repairs SO FAR. I hope the slab is SO dry that the issue of reverse curl doesn't become an issue. But, that will take 3-4 months to know for sure. But that is the informed risk the customer had to take.
After we finished the job, I was talking with the church elder. He ended up telling me the real story. When they built the main church, they took all the excavation & debris and filled up a pond. 50+ years later they went to build this building where that pond had been. So, when they went to build the building they didn't have a great base which is why the slab turned out like this. He told me when they began to dig out the pond they hit the natural sub surface pond wall and it was like a river opening up. They thought they had hit a water pipe but it was just the substructure of the pond. Over the long term it will be interesting to see the performance as I just want the customer happy. This was the nicest customer (church building committee) I have had in recent memory and I want them to be a good reference & happy.
RE: Concrete doesn't crack - CC Solutions - 12-22-2012 03:06 PM
We hand grind for $70 an hour. So $2k would get you a couple guys for a couple days. I would say my guys would grind those joints in less than a day. But I would think if the floor has cracked that much the slab has settled and must be undulating quite a bit.
RE: Concrete doesn't crack - eaadams - 12-23-2012 11:45 AM
$70 an hour just labor labor or including equipment / generator / diamonds etc...?
RE: Concrete doesn't crack - CC Solutions - 12-23-2012 09:50 PM
$70 total... Travel, lodging, meals, equipment, everything is included.
RE: Concrete doesn't crack - eaadams - 12-26-2012 12:58 PM
Well sir. Too bad we don't live closer to one another. I would send you some work next month.
RE: Concrete doesn't crack - CC Solutions - 12-26-2012 01:02 PM
Well around here they just have a laborer use a grinder and attack the floor. Laborers cost the GC about $40 an hour.
I bid work nationwide, and I actually beat contractors in Washington, Georgia, Delaware etc.
It destroys my profit if I have to make numerous trips though. I want to do everything in one shot.