White powder in wall

[mahhniks]

Hi, why do my walls have white powdery substance? My contractor said it is because of water coming externally when it rains. Need advice on what to do?

 

[JoeD]

It is effervescence from moisture.

 

[mahhniks]

How can I treat that? I mean remove the white powder and make look like cement again?

 

[JoeD]

The powder will brush off but then you need to address the moisture issue. Find where it is coming from and repair the issue.
If this is a basement maybe all you need is a dehumidifier.

 

[mahhniks]

Thanks JoeD, should I place epoxy on the other side of the wall since the external wall is exposed to rain?

 

[Sparky617]

Thanks JoeD, should I place epoxy on the other side of the wall since the external wall is exposed to rain?

Is the backside of the wall above grade?