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How are you addressing cracks?
08-11-2011, 08:03 AM,
#1
How are you addressing cracks?
I'm not talking about those kids running around with their pants half down... I don't understand that whole thing. I know as a teen you want to do something unique that upsets your parents, but in my day we grew our hair over our ears and kept our pants on.

The cracks I'm talking about are concrete cracks. I have a client that tried to seal his cracks around a group of trenches and his method failed, the flooring got wet and the patch and adhesive broke down. I asked what he tried and he told me he chipped out the gunk and debris and filled the cracks with an epoxy that took 2 hours to set and about 6 hours to harden.

Now he is asking me to recommend a repair.

My first thought is the vapor retarder is damaged at the trenches so moisture is a real problem (he did install a mitigation system on the new concrete in the trenches). I also really wonder how well the joints could have been cleaned using a chisel and a hammer. And then the epoxy that doesn't set for two hours could have drained into the subsoil and left voids. So my recommendation is this:

Clean the joints with a chasing grinder. Apply a mitigation epoxy to the concrete cracks as well as possible, the sides, edges, bottom, just get it in as good as he can. Then install a semi-flexible epoxy to seal the joint. I don't want to use an epoxy that is harder than the concrete itself or if the joint does move something will break, and it may break inches or feet away from the joint. It could cause an ugly meandering crack.

He could also use a two-part urethane as long as it is traffic bearing. Some of these semi-rigid products can stand up to cart traffic, resist crushing from heavy loads and actually stretch a bit if a joint shrinks. That's the type of product we want in these cracks.

If anyone has any other suggestions please chime in, or if you just enjoy my stories of struggle and strife, let me know!
JD Grafton
Concrete Answers for Flooring Problems
[email protected]
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08-14-2011, 08:16 PM,
#2
RE: How are you addressing cracks?
Enjoying the stories of life myself.

How old is the concrete in those trenches he dug out and filled? Maybe it just needs more time to set.

Did you do some rapid rh tests on it or uh in it? Trenches are just like wild cards.
Stephen Perrera dba
Top Floor Installation Co.
http://www.tucsonazflooring.com
http://www.floorsavior.com
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08-14-2011, 09:34 PM,
#3
RE: How are you addressing cracks?
The concrete is GREEN... Brand new. The moisture is coming through the cracks, the green concrete has Utzen on it. Wink
JD Grafton
Concrete Answers for Flooring Problems
[email protected]
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08-19-2011, 03:56 PM,
#4
RE: How are you addressing cracks?
1st) Idiots for trenching a new green slab. What a waste of man power for not planning it out.

A few questions:
1) What was the flooring that got wet? And what does that mean? If it got wet from vapor emissions from the bottomor did it get wet from the top?

Is it a crack in the trench? Is it a active (doweled) or inactive (sawcut) joint? If it a trench that has cracks on both sides I would weld the two together with a high viscosity injection like Roadware 10min Concrete Mender to try to keep the stresses on the slab at the main joints. If the joints are active then you have no guarantee that the crack will not telegraph through the top flooring. You can use a semi rigid as you describe and hope for the best. How do you address trenches under VAP?

Our local VAP guy is doing VAP over some trenches for us next week. I'll ask him how he did it.
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08-19-2011, 04:20 PM,
#5
RE: How are you addressing cracks?
The concrete in the trenches is new. The surrounding concrete is old.
The vapor retarder was compromised when the trenches were cut. The moisture is coming through the joints. The flooring is vinyl sheet. The trench was doweled and for the most part stable, but the concrete will cure for about 30 years and may shrink a bit over that time.
Roadware is a good product, like I said, I use a polyurea semi-rigid.
JD Grafton
Concrete Answers for Flooring Problems
[email protected]
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08-19-2011, 08:17 PM, (This post was last modified: 08-19-2011, 08:23 PM by Ernesto.)
#6
RE: How are you addressing cracks?
Address this one for me. Went 20 feet across living room.
I see dirt down there.
Oh heck, this should be in the other thread, that ain't no crack. It's the Grand Canyon. Big Grin


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Stephen Perrera dba
Top Floor Installation Co.
http://www.tucsonazflooring.com
http://www.floorsavior.com
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08-19-2011, 08:26 PM,
#7
RE: How are you addressing cracks?
Yowsa!!! That one is going to cost some money to fix.... Oh wait, it may be big enough to pack hydraulic cement in the crack. I just used some stuff that comes in a pail, costs $30 and dries in 3 minutes!

Put it in a trench or hole that you find, and epoxy right over it.
JD Grafton
Concrete Answers for Flooring Problems
[email protected]
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08-19-2011, 08:32 PM,
#8
RE: How are you addressing cracks?
Yea, and whats the correct definition of that void in the slab? I've seen concrete guys do that alot back in the 80's. Thats when this place was built.
Contractor apparently did this all through the hood. The next door neighbor(tile guy) had the same exact thing and thought some slipsheet would help. hee hee....not! It's a mover.
Stephen Perrera dba
Top Floor Installation Co.
http://www.tucsonazflooring.com
http://www.floorsavior.com
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08-19-2011, 09:00 PM,
#9
RE: How are you addressing cracks?
Definition? It's a crack. Big, but a crack. If it moves, oh well! Either you can honor it through or hope it is stable. I'd prefer the later, you can always cut a nice joint in the finished floor.

Fill it with cement, epoxy over it to seal it well, and put flooring on it. It will hold up. Wink
JD Grafton
Concrete Answers for Flooring Problems
[email protected]
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08-20-2011, 06:40 AM,
#10
RE: How are you addressing cracks?
I remember now, they used to call it a zip-strip. Now all it needs is a zipper to pull it back together. Big Grin

The way I'd honor that is to fill it with foam, seal the top and float a floor over it.
Stephen Perrera dba
Top Floor Installation Co.
http://www.tucsonazflooring.com
http://www.floorsavior.com
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