[325_man]

I am trying to finish my basement and did a lot of prep-work before putting up the insulation to the concrete wall. I plan to use XPS (extruded polystyrene) and then frame in front of it.

In inspecting the wall, I noticed an area of the wall that was discolored and had about 2 feet of crack. I started tapping on it and picking the crack with a chisel. It started to crumble. So, I decided to patch it with hydraulic cement patch. Well, that was 2 weeks ago.

Last night, I started to work on other things and notice the hydraulic cement patch is covered by white powder (see attached picture). I think it is efflorescence.

I am confused on how the efflorescence could appear on the patch only, but not on the surrounding existing concrete, or on other parts of the basement.

Do you think I have a big problem?
Since I will cover the wall with XPS (extruded polystyrene) panels, do you think I should worry about it?

Thanks,
Nick

 

[concretemasonry]

You do not "cover" a wall with hydraulic cement. It is meant to be forced/applied into a narrow and hopefully a cleaned out crack or joint because it is quite dry, but it needs to be confined (not coated) so it can expand to the sides and seal the joint. Then, then any leakage, if there is some less than the rest of the wall can be coated with some sort of a coating.

Efflorescence is actually a good thing because it tells you where the water (and how much) is coming through a surface.

Obviously, you have a lot of moisture on the other side of the wall from the soil with a large pressure to force it through the wall on a steady basis.

Dick

 

[325_man]

You do not "cover" a wall with hydraulic cement. It is meant to be forced/applied into a narrow and hopefully a cleaned out crack or joint because it is quite dry, but it needs to be confined (not coated) so it can expand to the sides and seal the joint. Then, then any leakage, if there is some less than the rest of the wall can be coated with some sort of a

I was not clear on how I apply the cement. I did it as you described.

 

[stadry]

difficult to source the cause of that crk but i'd guess its from a cold jnt stemming from when the orig conc was placed - delay in 2nd trk or lack of satisfactory vibration to consolidate both loads - who knows ? whatever the cause, there it is :yes:

decent article @ http://www.delawarequarries.com/cleaners & wikipedia/many others,,, in your case, it may be easier to excavate to approx ext location & waterproof the area,,, typical bldg code only requires 3mil dampproofing coating,,, typically asphalt emulsions get applied w/no or little flexibility/strethability so cannot bridge crks.

bsmt efflorescence is typically lime salts from soil acids in solution w/rainwater,,, wtr runs downhill & winds up against your fnd walls :furious:

 

[325_man]

I don't know if it makes any different, but the house was built in 2004. The wall was covered with fiberglass insulation blanket since then. I have not seen any water leak/puddle from this crack. So my guess is that it doesn't have leak issue, just a weak concrete spot. That was my original thought.

I'm hoping to ignore it and cover it with the xps insulation, but I need to know if that is a wise thing to do.

 

[Ameri-Dry Guy]

Well Nick, I think you should be fine, depending on the manufacturer of the hydraulic cement it could very well just be a not so good batch or depending on when you put the patch on it could have absorbed some ground water before it cured and it is just leaching the lime out. I would scrape it down and paint it with drylock and call it a day.

-Ameri-Dry Guy