Thread: What would cause this? Stains on a new foundation

There are white stains (efflorescence) on the foundation. However, it is only in between the stairs. At first I thought it may be snow accumulation, but there are no stains on the other sides of the stairs.

The building is a 2009 construction.

The town houses have similar stains in all the same places.

The gutters above this area were fine.

What would cause this?

Thanks


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My Guess ( based on this photo ) is urine stains.
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Water management issues from downspout and water spigots?

Efflorescence
Water vapor is migrating to the surface carrying the mineral salts from within to the exterior.
• First: There must be water-soluble salts present somewhere in the wall.
• Second: There must be sufficient moisture in the wall to render the salts into a soluble solution.
• Third: There must be a path for the soluble salts to migrate through to the surface where the moisture can evaporate, thus depositing the salts which then crystallize and cause efflorescence.
All three conditions must exist. If any one of these conditions is not present, then efflorescence cannot occur.

In the photos it appears the parging maybe be giving up the salts rather than the concrete foundation.

Cold joint in the foundation wall.

That is my guess.

Of course, though, it is water causing that efflorescence, but the cold joint is allowing the problem to be located there.

I doubt it is urine.

Originally Posted by Jerry Peck

Cold joint in the foundation wall.

That is my guess.

Of course, though, it is water causing that efflorescence, but the cold joint is allowing the problem to be located there.

I doubt it is urine.

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OK I see the hose bibs above the wet spot ( water )

If It's a Cold Joint it sure has a Big Hump in the Middle.
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Originally Posted by Billy Stephens

If It's a Cold Joint it sure has a Big Hump in the Middle.

Yep, not uncommon for cold joints, that's where they discharged the last of the previous load of concrete. They paid for that concrete and they want it all out of the truck, "Jus' put er right chere." is what they tell the driver.

Also common is for the cold joint to taper off like the slump of the concrete from the workers trying to keep the part done full, letting the rest just slump down and away from the working area.

Third photo -
No downspout installed on end unit, it is installed around the corner. Large roof - undersized gutters/downspouts, overspill in heavy rains against foundation.

Thanks for your input,

I buy the "cold joint" theory. It for sure is not urine, I opened the exterior water valve seconds before taking the picture. Sorry for the confusion.

Anyway, to the best of your knowledge, is the parging enough to protect the foundation? Or should the foundation be repaired in these areas?

I'm guessing the only way to find out is to remove the parting to see?

Thanks
Zane

........it's where the salted-snow ends up when the stoops are shoveled?

Originally Posted by Zane Remenda

Thanks for your input,

I buy the "cold joint" theory. It for sure is not urine, I opened the exterior water valve seconds before taking the picture. Sorry for the confusion.

Anyway, to the best of your knowledge, is the parging enough to protect the foundation? Or should the foundation be repaired in these areas?

I'm guessing the only way to find out is to remove the parting to see?

Thanks
Zane

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You could Clean and Seal the Area.
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Originally Posted by Gregory Booth

........it's where the salted-snow ends up when the stoops are shoveled?

I doubt it, as there is no efflorescence on the outside side of the stairs. What are the chances that people only shovel snow in the middle?

Originally Posted by Zane Remenda

I doubt it, as there is no efflorescence on the outside side of the stairs. What are the chances that people only shovel snow in the middle?

...........the stairs are pre-cast and set in place--they would not neccessarily react to salt/snow mix...........Greg.

Was the inside foundation wall exposed in order to confirm a cold joint?

Originally Posted by Raymond Wand

Was the inside foundation wall exposed in order to confirm a cold joint?

Unfortunately, The basement walls were finished from the inside.

You live where you get lots of snow, and use salt and sand to keep the roads safe. Walk up to the front door stamp off the slush off you boots then shovel it off.
The large pile of snow mixed with the salt is wicked into the parging leaving a nice stain.
Use the hose and a stable brush and wash the salt lick of the wall.

If you look at the pictures you can see that the unit on the left has a downspout at that location and the unit on the right (had) is missing the downspout in that location.

I suspect that roof run off is being absorbed by the concrete causing the stains.