Concrete - White Chalking

[Richard Seay]

What causes the white chalking in areas of concrete slab's visible edge. This is a five year old slab foundation. Thanks

[Michael R. Boyett]

Probably http://www.factsfacts.com/MyHomeRepa...lorescence.htm

[Marcel R. Cyr]

Originally Posted by Richard Seay

What causes the white chalking in areas of concrete slab's visible edge. This is a five year old slab foundation. Thanks

Richard; I do not see any visible signs of weep holes in the bottom course, is it possible that they were not installed?

If that is the case moisture on the back side of the brick is finding it's way down and out under the bottom course of the first course of brick and assumed installed counter flashing.
This would introduce this kind of efflorescence on the surface of the slab edge as seen in the photo.
Just a thought.

Marcel
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[William J. Decker]

Grade too high. Water wicking up the concrete foundation.

"Recommend thath the grade around the house's perimeter be lowered so as to allow at least 6" of foundation exposure below the brick / concrete interface as a guard against water infiltration."

[john bubber]

Originally Posted by Richard Seay

What causes the white chalking in areas of concrete slab's visible edge. This is a five year old slab foundation. Thanks

many want to raise & slope the grade (fine- raise it....4' high) and extend downspouts extentions 1/2 mile (fine-extend all ya like) or maybe mudjack a slab or 2 thing is......concrete, bsmt walls, bricks need to be protected/waterproofed when below ground....so, FIRST....HO`s would be BETTER off applying 'something' over bricks,slab etc BEFORE raising the grade. this chtt can wick...... UP AND DOWN, got milk?

its not an area of expertise for most builders, thats when this chtt should be done....at the onset-when house is being built.

http://www.nbc5.com/unit5investigate...38/detail.html

[Carl Brown]

Any sprinklers hitting the wall?

Do you live in a freeze and thaw climate?

Was the job done in the winter time during freezeing temps?

[Richard Seay]

Weep holes are present. House is located in north Texas. 2 to 4 inches of slab were visible above grade. No sprinkler system. Chalking was only present on areas of slab poured two years after original slab. Your opinions are welcome.