Cracks in concrete flat work

[A930Rocket]

What are you guys using for cracks in concrete flat work? Stuff I’ve bought at the big box stores, have always been a failure, both short-term and long-term.

I need something for hairline cracks up to 1/8” on exterior concrete flat work.

Is there something that is easy to use and has good long-term results?

[gregpark]

Unfortunately, due to temperature swings, expansion and contraction of the slabs means any fix is short term

[TimT]

You need a low viscosity product either a isocyanate, acrylate, or polyurethane that penetrates or wicks into the crack.. Products you wont find in a big box store... You can try building supply outlets... that supply bridge and heavy construction contractor..

We have used products by Sika, Transpo, etc on bridge slabs and superstructures..

Ardex

Crack injection

https://sealboss.com/concrete-crack-mender/

https://transpo.com/products/applications/bridge-preservation/bridge-crack-sealers/sealate/

[cabmandone]

"There are two types of concrete, that which has cracked, and that which is about to crack"
Concrete guy told me that one. I thought it was funny but it's so true.

[MBAtarga]

I've heard Sikaflex recommended by some.

[Rtrorkt]

this is why you need control joints in any pour

[A930Rocket]

Originally Posted by cabmandone

"There are two types of concrete, that which has cracked, and that which is about to crack"
Concrete guy told me that one. I thought it was funny but it's so true.

I tell homeowners, concrete is going to do two things: it’s going to get hard and it’s going to crack.

That said, I want to make sure it’s at least looking as best as I can get it for a new house.

[A930Rocket]

Thanks, Tim and everyone else!

I’m going to the house tomorrow, so I’ll take a look and think about options.

[cabmandone]

Kinda funny, after I looked at this thread, I got reels on facebook fixing cracked concrete.

[A930Rocket]

Here’s the front porch. It doesn’t have any cracks, but the finish is uneven and it’s been abused.

I’m not sure if a concrete stain is the answer. Has anybody used any kind of application, like Ardex? I don’t want to stain or paint it, is that a frequent maintenance item?

[gregpark]

I use products such as Ardex, Henry's, Feather Finish, etc but as levelers or floor stoning (I'm covering the slab with a floor covering). I can guarantee the color of any of those products will be different from your existing concrete (darker). There are guys out there who can cap the concrete with endless options of color and textures but it ain't cheap. You could simply apply sealer which might just jazz it up enough for sale. It would certainly be the cheapest and easiest solution

[URY914]

Another option would be grinding/polishing. Basically a walk behind floor sander that will take the high spots down. Go you youtube to see some examples. For that size area you could rent a machine and do it yourself. But the color may not be uniform across the entire area.

[Tobra]

Didn't they figure out the secret for Roman cement?

[zakthor]

Originally Posted by URY914

Another option would be grinding/polishing. Basically a walk behind floor sander that will take the high spots down. Go you youtube to see some examples. For that size area you could rent a machine and do it yourself. But the color may not be uniform across the entire area.

My vote too.

My fix for cracks is to rent a saw and cut the problem section out and pour it again more better.

[TimT]

the secret for Roman cement?

Pozzolans, or Pozzolith

Its just a fact of life that concrete cracks.. mesh or reinforcement is used to really control the crack once they inevitably happen..

"Fixing" a crack will never restore the integrity of a monolithic slab... Using low vis penetrating type repair materials and sealers is to control water intrusion into the slab..

Expansion of water during freeze thaw cycles is damaging.. as is water and sodium ions in contact with mesh or reinforcement.. I'm not sure how popular the use of epoxy coated, stainless clad, or stainless reinforcement is, or galvanized reinforcement is in home construction.

cut the problem section out and pour it again more better.

The problem with this , is you introduce other weak joints in the slab..to do it properly the cut joints need to be roughed up, coated with bonding agent, and reinforcements doweled and grouted into the remaining slab.. to do it properly is time consuming, and expensive, and has impacts on the schedule..

[gregpark]

That plain Jane cement porch slab is a perfect substrate for some beautiful flag stone ya know

[A930Rocket]

Originally Posted by gregpark

That plain Jane cement porch slab is a perfect substrate for some beautiful flag stone ya know

I’m embarrassed to say the prez of the company wants to cheap out. It’s crazy. Epoxy is out due to long term issues. Stain won’t cover it and getting someone to do the other options will be a challenge.

[TimT]

Just do nothing, I'm sure the homeowner will be putting planters, Adirondack chairs, an outdoor couch or something that will take up and cover a lot of that area

[gregpark]

Grab a remnant of indoor/outdoor carpet from the bargain bin of the local flooring shop. Cheap, easy and it'll look like a hundred bucks!

[cabmandone]

I'd etch it and seal it. But that's just me.