Trick Question

no pic for me.

Yep: your post is cursed with a black box with a big X in it.

Concrete will wick up only as high as the available water that is available in your ground.

You might get only a bit of saturated ground , or you may have a lot. Depending on seasonal changes.


ED

Now I get a photo.

Was I ever mistaken in my first post. YES

How old is that step, if it is still curing I would not worry too much.

But if it is at least 6 months old you might be concerned.


ED

I poured the step 31 years ago. It's on sand that's dry as a bone.

31 years.

it's cured.

Do you use a de-icer in the winter, that can discolor concrete?

Maybe some kind of cleaner came from inside the building.

ED

de-nagorg said:

31 years.

it's cured.

Do you use a de-icer in the winter, that can discolor concrete?

Maybe some kind of cleaner came from inside the building.

ED

Click to expand...

No and no to de-icer or cleaner.

No wet looking area today. It all looks dry.

SeniorSitizen said:

No wet looking area today. It all looks dry.

Click to expand...

No dry pics now. It's snowing on it.:surprise:

Could it be a small growth of concrete mold that shows when dampened or the light is just right?

A 10% chlorine bleach solution applied in warm weather will determine that. Rinse well.

SeniorSitizen said:

No wet looking area today. It all looks dry.

Click to expand...

If it were moisture coming up through the concrete, it wouldn't dry up that quickly.

I think what you saw in that picture you posted was condensation forming on the SURFACE of the concrete. You have to remember concrete is heavy as sin. It cools down at night, and it takes a good few hours for it's surface to warm up during the day. During that time, as the air temperature (and humidity) rises, condensation will form on the still cold concrete. That makes the surface of the concrete wet, and it's easy to mistake that for moisture rising up through the concrete.

Also, if you live where temperatures drop below freezing in winter, then the water expanding as it freezes inside the concrete will cause something called "spalling" where the surface of the concrete breaks off in chips. Condensation on the surface of the concrete won't cause spalling because the moisture isn't deep enough in the concrete.

Nestor gets the A+ on the test question and has bragging rights as long as he wants. Good job.

The dry area in the upper right was 64°F ( 17.7c ), damp area was 61°F ( 16.1c ) and the dew point temperature was 62°F ( 16.6c).