Help!! New Garage Floor Cracked..

How did this pass inspection before the pour? No reinforcement? Is that the way it`s done around there? This will not get better, sorry.

 

My guess is that it being a hot day, the crew added too much water to make it workable. Then they over worked the top finishing it. That happens alot. Probably did not use any proper curing for the hot temps. That generally gives you surface cracks and will probably eventually spall. One thing you can do is have it cored at 28 days and have a testing agency do some compression tests to see what the strength of the concrete is. If it is below 3000 psi, you have a good case against the contractor, depending what your you had as a contract stating what he was providing. A core will also show the depth of the spalling and cracking. My other concern is it being only 4" thick, including the embedded pex. That's my opinion, and I'm a licensed professional Civil engineer.

 

Without making any assumptions here at all, the cost of the job often has ramifications on the result.

Often times the cheapest price doesn't provide a lot of value...

If I had paid a premium price for that slab I would be pissed, If I got a bargain basement price I would live with my decision.

 

I haven't read the entire thread but didn't see it in what I did read here, so I was wondering if anyone checked the sub grade condition? Was any compaction performed? Was any gravel put down?

 

Over working the finish would account for the aggregate showing. I learned concrete finishing from an old gentleman who was the head of several dam and powerhouse projects. He taught me that the prep was more important than any other part of the pour. I've never seen anyone pour on top of sand like that before... not saying it shouldn't be done, but I wouldn't.

 

Concreting was one of those jobs (Prick of a job) I did for a short time before joining the Army. From what I learned if the guy is reputable he will take it all up and start again from the form-work up.

If he doesn't do that, his $$ better pay for a better concreter to do it all again right.

Sorry to hear what happened man.

Doc.

PS, A 'Slab' is also a slang term for a 24 pack of beer, Grits when you say you have poured over 4000 slabs.................was that down the throat?

 

Don't want to mess any feathers up here, as all are good valid points.
Just one clarification....
Fibermesh is a good thing, and acts the same as steel re-bar...Yes it does.
I have poured literally hundreds of thousands of square feet of this stuff, and the only drawback is that it has a fuzzy hair coating that takes a small bit of time to wear off the surface...
Fibremesh will pass any Wisconsin Commercial Building Code.
Also floating slabs, done properly are not a bad thing. Many building codes in the south approve them for commercial properties. It is common practice to pour a floating slab first, then put up the structure...in fact that is the only way a floating slab can be poured.
One final note....there may not be any local codes for a garage (unattached) where this gentleman lives...not uncommon in the boonies...
The actual weight of the structure will not affect this problem very much, as it is spread out over many lineal feet of concrete.....the problem will show up when a vehicle is parked in there, especially if it has narrow wheels, where you get a large concentrated load...
Agree totally, NOW is the time to stop this construction and get this settled...it will only get worse, and cost everyone more money to fix.
If it were me, I would (after the obvious professional opinions come in that it is crap) have them saw cut the floor completely out (about 6" in from the stud walls), replace all piping, insulation, etc, then pour a decent 6" reinforced floor tied to the remaining perimeter with rods, and expansion board...enabling you to get the balance done..
Again, JMHO..
Good luck,
Bob

 

Yes, I have heard that too.

I spoke in my previous post from experience that I had on a building slab and what the contractor that I now use said regarding fibermesh. The contractor said that it is "o.k." for sidewalks.

Again, I won't use it. The rebar will keep the floor in place. The lines are cut in the concrete to encourage the floor to crack at the lines. With rebar, the cracks/expansion joints will stay in place. I have not seen where fibermesh will do this.

Neal

 

Jeez man, makes me appreciate the good luck I had with my garage build, although I thought it had been ruined. It started raining before the finishers got to work the floor, so they did the best they could when they could, and kept it covered when they couldn't. Keeping it covered helped it cure slower, so it wasn't all downside.

Not sure if they're legal here in WV or not, but certainly people build that way and it works if they're lucky enough.

I hired a union guy, and ended up with a 2' foundation with rebar in it, and 3 courses of block above that. The floor is built on a shitload of bank run sand/gravel, then visqueen, rebar/screen, and concrete. It's not going anywhere and it doesn't get damp. Seemed expensive then, seems worth it now. Wish the foundation on my house was built so well.

 

It does not look to be a settlement issue. I've seen slabs placed on sand which is fine if the moisture content is good and if it is compacted properly. We design slabs for huge manufacturing facilities which commonly use fibers in lieu of steel they are fine to use, if the proper amount is used. The hot temperatures are most likely to blame, The PCA Portland Cement Association has a publication that has a whole section on Plastic Shrinkage cracking which states they occur in hot ambient temperatures with rapid evaporation. Doesn't look like the proper precautions wre taken. How was the concrete cured? Was it covered, wetted, curing compound.

 

Don't ever believe that, it is a load of BS. No way will that garbage ever replace steel re- enforcement.

That job I had done, I fell for it, poorest finished worst concrete job I have ever seen. The fibermesh will never give you results as solid or properly held together as heavy screem mesh and rebar will.

Take a look at any heavy industrial project involving huge quantities of concrete and you will also find huge quantities of re -enforcing steel.

Any building code that accepts fibermesh is a joke.

 

As happens many times, unfortunately, these threads tend to get carried away, as well as personal.
Easy to check codes...I worked with them for ~45 years. They are not opinions, or jokes, and are printed in writing.
I am sure anyone has had positive or negative experiences with most any product available.
So Blue One, I will not bother responding to your private message you sent to me....my opinion is based on facts and codes that can be easily verified....
File Format: PDF/Adobe Acrobat - Quick View
Complies with National Building. Codes and ASTM C III6/C III6M,Type III fiber ... DO SPECIFY. FIBERMESH 150 FIBERS: • Reduced plastic shrinkage cracking ...
And here is full page:
http://www.fibermesh.com/downloads/Fibermesh 150.pdf
I will refrain from posting further on this thread, as I don't want it to get ugly.
I have only posted my experiences as stated over ~45 years, and have the facts to back them up..One of them just shown here.
Good luck on your garage build.
I hope it works out well for you.
There are a lot of great factual opinions given to you on this thread. Pick the ones that make sense to you, and then do what YOU are comfortable with..
'Cheers,
Bob

 

I figure if the 18"thick runways at the local airport don't need any rebar, then my garage slab doesn't either.
Been 6 years and not one crack and the control joints did thier job.

 

Any news as to what the contractor had to say? Is he going to replace it?

 

A. I am going to bet the frost cycle in the upper Mid-west is slightly different than yours in Reno.
B. You might just be lucky.
C. The concrete in an airport runway is substantial different than your garage floor.
D. The fact that you survived jumping out of an airplane without a parachute doesn't mean that, in general, it's a good idea.

Don't be silly.

 

You live in a frigin' desert dude, your shit hasn't moved in a hundred years.

 

Slab too thin.

Poor subgrade prep.

Dry mix placed.


Do over.

 

Did you read the brochure? Per the manufacturer, Fibermesh 150 is not to be specified for crack control for external stresses, or as a replacement for moment or structural steel. Given those restraints on it's use, how do you consider it a replacement for conventional steel reinforcing?

Bob

 

My point exactly Bob. If you think you can pour with just the fibercrap and not put in the steel mesh and rebar you are sadly mistaken.

The lack of quality and strength of the end product will show.

 

To be fair, there are fibers that can serve as primary reinforcement, replacing conventional steel reinforcing. They are very expensive, usually steel, or a mix of steel and polyethylene. They are also very expensive and have very high dose rates; some requiring as much as 40 lbs per cubic yard. Because of the cost, which is much higher than conventional reinforcing, they're generally only used in applications where steel placement is difficult. The polyethylene fibers being sold as a substitute for reinforcing are being used incorrectly, but they're being promoted as such because they're a high profit "add on" for the ready mix producer. There usually added at a dose rate of 1 to 3 lbs per cubic yard, and do little more than provide some protection against shrink cracks which is their real purpose.

Bob

 

Am I on "The Garage Journal"

 

http://www.fibermesh.com/downloads/Propex_ER_17.pdf
Read the conclusion....(if not all of this article)

http://www.fibermesh.com/downloads/Propex Roundys Case Study.pdf

http://www.menomonee-falls.org/index.aspx?NID=655

 

No articles, testing or manufacturers claims will convince me on fibermesh so you might as well not try.

There has always been someone trying to convince you how good something is.

As an unrelated example I was looking through old National Geograpic magazines dated from 1927.

I found full page ads extolling the advantages and virtues of the newest lead based paints.

I will never accept fibermesh as anything other than a bad idea that is improperly used and promoted.

 

A. I am going to bet the frost cycle in the upper Mid-west is slightly different than yours in Reno."

I'm sure the frost heave is significantly different in Wisconsin than it is is in Northern Nevada, but many of comments in is this thread have stated reinforcing steel is required in concrete slabs.....and that only a hack would pour a slab without steel.
That is just not true in my area and I'm sure it is that way in other locales as well.
Slabs are routinely poured in my area without any steel. As a matter of fact the county building department used to require an inspection to ensure mesh was placed in slabs.They have since changed policy and now allow slabs to poured on grade without steel of any type. They still inspect the steel in the foundations.

"B. You might just be lucky."

I'm damn lucky man, but I also have the ability to pick the brains of the Civil Engineers who do concrete design work(including runways) at my place of employment

"C. The concrete in an airport runway is substantial different than your garage floor."

Very different indeed, but still no re bar in it.....

D. The fact that you survived jumping out of an airplane without a parachute doesn't mean that, in general, it's a good idea.

Now that's just silly....

"You live in a frigin' desert dude, your shit hasn't moved in a hundred years. "

Except for the estimated 620 earthquakes we had in 2008.,,but your commment does reinforce (ha ha) my argument that different areas require different buliding methods..

Not trying start a flame war here, but I don't want everyone to read this thread and think just because they did not get steel in thier slab it is going to look like the OP' effed up job...

 

think i would have to get another expert opinion before i would let the building go up any further... if your just building the house and garage, your going to have to live with it like that for a while, and i dont think i could, especially with the money you have spent to have the job done correctly..

 

Bottom line is the man should pay for an hours worth of an engineer to access the job (right now). Nobody seems close enough to go take a look at the job for him.

Here on the lovely sands of Cape Cod, they still will let you pour (residential) garage floors without rebar or screen. But mostly no one does, as the price of rebar/screen isn't cost prohibitive to add (and things are VERY expensive here). You don't see much fibermesh anymore, it was like a fad there for a while but seems to have fallen out of favor. We DO have to set up frost protection, most every garage is built on a 3' 8" wall buried up to all but 4". Floors are normally done after the structure is up.

One thing that hasn't been mentioned, did the contractor power trawl the floor? I would have to think he did, as in that heat, an uncovered floor would flash pretty quick in that heat even with retard added. Reason I asked was power trawls tend to pound the water to the top, and the slurry tends not to be a problem (as the floor can be worked quicker over a wider area).

 

sweet!

 

I also was an oversight engineer for sams club and walmart, we poured hundreds and hundreds of yards of concrete. If that was on our job, I would be having the contractor remove and replace the panels that looked like that.
If it was my money buying the slab, you can bet big money that wouldnt be there.
Agreed the contractor didnt know what he was doing, also another note, seems that if the sawcut would have been deep enough, it would have cracked where you wanted.

 

Do you have a written agreement with the contractor? If so, you should follow the terms of the agreement with regards to non-compliance and at a minimum, notify him of your displeasure and anticipated non acceptance in writing. Ask him to fix it in writing. Make him reply in writing.

Ain't construction fun?