Cracks in Concrete Floor

[INTELLICON]

Since our house was built three years ago, we have about five or six cracks in the basement floor. The cracks range from about 1/64" to 1/8" in width. I had a home inspector and brick mason look at them and both said they were stress cracks caused by shrinkage of the concrete and posed no structural problem. There is no moisture involved.

Since we will probably sell the house in a couple of years and move to a town house or condo, I will need to fill them. Home Depot and Lowe's have dozens of fillers ranging from epoxy fillers to "caulk."

What would you folks recommend?

INTELLICON

[garager]

As long as its no water problem as you stated, anything that will match in color will be good enough. Epoxy won't stretch and most caulking will, so take this into consideration. You might want to make the small cracks a little bigger so more filler that goes in, will bond and work better.

[BHD]

I have never seen much success on sealing concrete cracks, as there there partly do so micro movements, expansion and contraction, micro shifting of the soils do to moisture or lack of it, and if there any movement usually the sealant will not stay as desired,

but normally concrete slab will crack about ever 10' by it's own nature,

I have seen people attempt to seal them and normally the end results are (over time) worst than if they had never been touched,

(and if there major cracks the slab probly is still moving, do to improper Base preparation, or weight distribution, or slab thickness, and with out fixing the problem sealing will only be a band aid type fix,).

Just an opinion.

[Velosapien]

Concrete will usually crack by its nature. This is normally taken into consideration during its design. Slabs are generally grooved every 10' to about 25% the slab thickness to keep cracks from continuing on. How much or how bad it cracks can depend on many factors. It might have had too much water poured in. It might have not been hydrated properly during curing causing it to dry too fast. Soil might be loose underneath, poor reinforcement, wrong kind of concrete mix, and so on.

The advantave of using epoxy to repair cracks is that it will form a structural joint that is actually stronger than the concrete itlself. It cures slow enough that it has time to fill in small crevices. If structural repair isn't required then epoxy is generally not necessary. For waterproofing only there are elastomeric foams that are a easier to handle. In most cases rapairs are better made by opening the gap a little more and removing all loose material so more repair material can squeeze in easily and all the way. Also, if the crack is wide enough, it best to repair it with more concrete. Hydraulic cement is very good for this because it expands as it cures, filling any voids for a water tight seal which also gives a better structural bond.

[franklie]

if you have what is termed "expansive soil" and the concrete was not reinforced with wire mesh or re-bar, regardless of which solution you choose from the answers above the problem will continue.

http://www.westcov.org/events/soil.html this is a link about expansive soils from Plumber Rick's neck of the woods.

http://www.usinspect.com/Soil/SoilPaper.asp this is a link from inspection website.

http://www.jcpreports.com/html/articles/expsoil.html another good article about remediation


http://web.umr.edu/~rogersda/expansive_soils/DAMAGE%20TO%20FOUNDATIONS%20FROM%20EXPANSIVE%20SOI LS.pdf (http://web.umr.edu/~rogersda/expansive_soils/DAMAGE%20TO%20FOUNDATIONS%20FROM%20EXPANSIVE%20SOI LS.pdf) a good technical report about soil expansion

[Velosapien]

If rebar or mesh is not used thats just bad news regardless. There's no way to solve that problem other than redoing it.