Concrete crack repair...suggestions?

[psyclenutt]

Great board here, alot of you have some crazy *** garages!! Sweet stuff!

I recently put a 30x30 of my own up. I had a local contractor pour the concrete. The pad was engineered, and the crew did the footing and re bar work as per plan. Soon after (when I say soon I mean approx. 60days) I noticed small hairline cracks forming, and now,(approx 180 days after pour) there are more branching out and originals are slightly larger in width. Now they are not huge by any means, maybe 1mm (0.040") is the largest. They are more unsightly than anything, and would like to know if you guys know anything that can be done in the way of repair. Any sort of filler?? Filler/sealer?? I have in floor radiant heat, so I am not about to drill or grind too, too deep.

Just wondering if any of you have had to deal with this, and what you did to repair it.
Thanks in advance

Dan.

 

[David Ferguson]

Most repairs seem to highlight the cracks and make them more visible. I would suggest that unless they are causing a problem (like the edges are uneven and present a tripping hazard), you just live with them. They are probably more noticeable to you than anyone else.

If you decide to paint your floor, then you have the opportunity to fill the cracks and paint over the result.

 

[67 455 Bird ragtop]

Most repairs seem to highlight the cracks and make them more visible. I would suggest that unless they are causing a problem (like the edges are uneven and present a tripping hazard), you just live with them. They are probably more noticeable to you than anyone else.

If you decide to paint your floor, then you have the opportunity to fill the cracks and paint over the result.

I'll second these thoughts.

 

[psyclenutt]

Nope, not a tripping hazard, but surfaces are slightly uneven (running hand/foot over crack proves it), I just thought to repair it in case the concrete where the crack is chips or flakes. Yes, you are right, it is not really evident to anyone until I point it out.
Thanks.

 

[IHI]

Good advise.

There are only two gaurntee's with concrete:
1. it will get hard
2. it will crack

you can do everything overkill/overboard to the enth degree, and no matter what, that big gray ******* will do what she wants regardless-EVERYTIME. You can put control joints in to show her where to crack, but if she wants to start someplace else...aint a dang thing your gonna do to prevent it...just how it is.

 

[Wardster]

You said the floor was "engineered". Does that mean they cut control joints and added expansion joints? The problem with cracks is that they allow water/solvents/salt/etc. to penetrate the concrete and potentially cause damage.

-Wardster

 

[rsanter]

You said the floor was "engineered". Does that mean they cut control joints and added expansion joints? The problem with cracks is that they allow water/solvents/salt/etc. to penetrate the concrete and potentially cause damage.

-Wardster

my concern would be the accumulation of dirt and oils...etc

at minimum I would look at using a seam or crack caulking for concrete and then paint the floor when its time.

I did not like how the seams or expansion joints in my floor collected the dirt and sawdust. filled them with the caulking and painted the floor. every thing sweeps up easily now.

bob

 

[Wardster]

my concern would be the accumulation of dirt and oils...etc

at minimum I would look at using a seam or crack caulking for concrete and then paint the floor when its time.

I did not like how the seams or expansion joints in my floor collected the dirt and sawdust. filled them with the caulking and painted the floor. every thing sweeps up easily now.

Exactly. I used a self-leveling urethane sealer on all my concrete joints, both inside the barn/garage and outside on the pads.

-Wardster

 

[psyclenutt]

No expansion joints required as per engineered drawings. I was asked if I wanted them, but chose not to. I did want to paint the flioor, so I will look into a sealer/caulk when it comes time to.
Thanks again for the ideas,
Dan.

 

[Jason B]

Most repairs seem to highlight the cracks and make them more visible. I would suggest that unless they are causing a problem (like the edges are uneven and present a tripping hazard), you just live with them. They are probably more noticeable to you than anyone else.

If you decide to paint your floor, then you have the opportunity to fill the cracks and paint over the result.

What ***** is, I can't believe someone doesn't make a kit to fill cracks to MATCH the concrete color you have. All these crack fillers never match the color right, and the cracks that you fill will stick out like a sore thumb.

 

[Wardster]

No expansion joints required as per engineered drawings. I was asked if I wanted them, but chose not to. I did want to paint the flioor, so I will look into a sealer/caulk when it comes time to.
Thanks again for the ideas,
Dan.

That big of a shop should have had control joints cut in it while the concrete was still green. Your engineer should have known better.

Is there reinforcing steel in the concrete?

-Wardster

 

[Kevin54]

No expansion joints required as per engineered drawings. I was asked if I wanted them, but chose not to.

I hate to say, but both parties should have known better. Just like IHI stated...the only guarantee with concrete is that it will crack. And a slab the size of yours (30' x 30' ) should have had a couple sawed in. You can still do it, and I would recommend it. That is why it is called a "control Joint". By sawing it in, you "control" which way that crack is going to run. Hairline cracks can be cosmetic, or it can lead to bigger problems. The good thing is that you have rebar in it. And I know that they push the fiber reinforced concrete, but it will crack and tear the fibers. The fibers help somewhat, but WILL NOT keep it from cracking. By having the fibers you can drop down on your PSI mix a little, say from 6000 / no fiber to 4000 / with fiber and both is supposed to be about equal. If it was mine, I would go back, saw in some control joints, let it crack in them, fill in the control joints with a joint filler, then finish as you want. You will always see the control joint even when filled, unless you have a tile over it, or if it is filled, sanded, and a self leveling epoxy put over it, but you will have the satisfaction of knowing that you more than likely WON'T have a crack running crooked as a limb from one corner to the opposite corner.

 

[SC-Eric]

What ***** is, I can't believe someone doesn't make a kit to fill cracks to MATCH the concrete color you have. All these crack fillers never match the color right, and the cracks that you fill will stick out like a sore thumb.

The problem is that no one has the same color of concrete. Even in the same slab you will have many different shades.

 

[psyclenutt]

That big of a shop should have had control joints cut in it while the concrete was still green. Your engineer should have known better.

Is there reinforcing steel in the concrete?

-Wardster

Plenty of rebar in it, not going to point fingers at the engineer, because I have seen pads bigger than mine without control joints cut in them, with little cracking in them. Since I posted originally, the cracking has not got any worse.
When I figure a way to do what I want, and it lasts/looks good, I will share the secret!!
Thanks again guys!

 

[psyclenutt]

I hate to say, but both parties should have known better. Just like IHI stated...the only guarantee with concrete is that it will crack. And a slab the size of yours (30' x 30' ) should have had a couple sawed in. You can still do it, and I would recommend it. That is why it is called a "control Joint". By sawing it in, you "control" which way that crack is going to run. Hairline cracks can be cosmetic, or it can lead to bigger problems. The good thing is that you have rebar in it. And I know that they push the fiber reinforced concrete, but it will crack and tear the fibers. The fibers help somewhat, but WILL NOT keep it from cracking. By having the fibers you can drop down on your PSI mix a little, say from 6000 / no fiber to 4000 / with fiber and both is supposed to be about equal. If it was mine, I would go back, saw in some control joints, let it crack in them, fill in the control joints with a joint filler, then finish as you want. You will always see the control joint even when filled, unless you have a tile over it, or if it is filled, sanded, and a self leveling epoxy put over it, but you will have the satisfaction of knowing that you more than likely WON'T have a crack running crooked as a limb from one corner to the opposite corner.

As far as knowing better, on my part...well...probably...I should have researched a little deeper. Like I said before though, I have seen pads bigger than mine without control joints, with slight (only slight) cracking. The amount of rebar that is in my pad would suggest to me that the cracking is but only going to be cosmetic. Who knows...I don't for sure. And with in floor radiant heat, I won't be cutting in expansion joints now.
Thanks again.

 

[IHI]

I nour area...though not as cold for as long, when they do garage slab radiant floor heat, they put down the lines, cover and tamp over the lines with sand, and then pour the slab....plenty of heat radiates through the sand into the slab so once it's upto temp...no problems at all, works just like a normal tube in slab set up. benefit....you can cut the concrete all you want with no fear, install swedge bolts for equipment, with no fear

 

[Kevin54]

And with in floor radiant heat, I won't be cutting in expansion joints now.

You can still cut a control joint and not worry about your lines. The joint does not go all the way through the concrete. Your slab is way thicker than the depth of the joint would be.

 

[IHI]

control cuts are typically 1/4" deep for every 1" thickness of the slab...if you have a typical 4" slab and your lines are within 1" of the surface, somebody goofed and did'nt anchor them well enough.

 

[Jaguar Fan]

You can still cut a control joint and not worry about your lines. The joint does not go all the way through the concrete. Your slab is way thicker than the depth of the joint would be.

in my mom's house, the garage has a stamping in it that says "post-tensioned concrete - do not cut, core or drill" or something like that. She has control joints that were put in with the original pour. you might want to make check for something like this as well.

 

[psyclenutt]

So... it's been better than a year that I posted this, and if anyone is interested, the cracks I have spoken of in the previous posts have not gotten any worse at all!! So now I will follow advice and caulk the cracks and then epoxy paint her up. Any other suggstions on product brands for this job?? Rustoleum is a big thing here these days with their paint. Good? Bad?? Is there better???
thanks again,
Dan.

 

[Gary S]

When I poured my garage, my Inspector told me that I better get a concrete saw and cut relief grooves in it. I did that the day after pouring the concrete, and a month or so later, all the grooves had a crack. The grooves put the cracks where I wanted them instead of at random. I fillled the cuts with a pourable concrete filler that stays flexible. The grooves change width now with the change in temperature.

 

[DB2]

Your hairline cracks were probably shrinkage cracks from pouring too wet a mixture. Did you do a slump test during the pour?

If the cracks don't get any worse I wouldn't worry about them, as they likely have no structural ramifications.

 

[MonsterCoatings]

Based on everything read I believe it is most likely shrinkage cracks.

Radiant should be installed deep enough to cut control joints but you would know better if you saw it during installation.

Crack repair material color is based on a large range of color averages. Concrete varies by region simply because the color of the sand from local quarries will change it slightly.

If you do epoxy I would recommend you either cut,fill then bridge the joint for a seamless look.
OR epoxy first then cut and fill after.

Different looks, personal preference prevails which you choose.

If cutting make sure to use a rail saw ideally, or very straight guide & carefully cut joints.

 

[Jason B]

Most repairs seem to highlight the cracks and make them more visible. I would suggest that unless they are causing a problem (like the edges are uneven and present a tripping hazard), you just live with them. They are probably more noticeable to you than anyone else.

If you decide to paint your floor, then you have the opportunity to fill the cracks and paint over the result.

What ***** is, I can't believe someone doesn't make a kit to fill cracks to MATCH the concrete color you have. All these crack fillers never match the color right, and the cracks that you fill will stick out like a sore thumb.

Hmm, seems there no is something to get a better match than the stupid standard grey color that never matches?

- anyone use this, or have any updates on their cracks?