I live in a house approx. 10 years old. In some of the areas in my basement the concrete seems to be disintegrating (white powdery substance forming and breaking slightly the concrete) where the wall meets the floor. What exactly is this and what can I do to stop the breakdown of this concrete?
Thanks,
Rob

You sure its not mold? Is this pre cast or poured concrete?
If its not mold that portion is effervescing. Effervescent is caused by moisture reacting with the salts in the block or concrete. To remove a strong detergent or Sure Klean acid. This will come back unless the moisture is lessened. After its clean and if the chipping is minor use Drylock sealer on those spots. The moisture bleeding to one spots and concentrate the salts and bleeds out to a white powder surface. Your not going to get rid of the salt in the material but if you keep that area dryer this should go away. Now the untreated areas could also could start to do the same thing. I would also recommend a dehumidifier to keep area dryer. This "salt" is also seen during springs on newer brick buildings. A sealer is applied to try and stop or slow it down.

Signed 21 boat

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White dust is common but can you describ in more detail the breaking down of the concrete? Is it chipping, flaking, cracking?