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Dirt coming up between floor and foundation wall. Also mold issue. Help?

Dirt coming up between floor and foundation wall. Also mold issue. Help?

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  #1  
Old 01-19-13, 10:02 PM
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Dirt coming up between floor and foundation wall. Also mold issue. Help?

Two troublesome issues in our basement -please see pictures....

1.) There is dirt being pushed up at the seam between the concrete slab basement floor and the concrete foundation wall. I am at a loss as to why this is happening and how to fix it. I measured the height of the cement floor and it is higher than the soil level outside.

2.) We are also having a mold problem on this concrete foundation. In one are that had a freestanding bookcase, there were water droplets all over the concrete wall. I wiped the wall down to remove the wetness and the fuzzy part of the mold. I will be bleaching it soon.

Should either side of the concrete wall be sealed? And if so, with what?

Thanks.
 
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  #2  
Old 01-20-13, 04:58 AM
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You say the floor is above grade? Do you have exterior water moving away from the footing of the house...gutters, downspouts, extensions??? It appears there is already a waterproofing coating on the walls, but it won't stop water seeping in at the seam. That water needs to be stopped from the outside.........preferably before you put down your new hardwood flooring.
 
  #3  
Old 01-20-13, 09:08 AM
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I also need to understand:

If your that inside surface with the mold is entirely exposed to the cold on the outside, your moisture is from condensation. That agrees with the space behind the bookcase being wet, as the bookcase would block the heat making the wall even colder.

As for the dirt being pushed up on the inside, is it cold enough for frost to be at work? Seems unlikely, but I don't know how cold you are down there.

Bud
 
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Old 01-20-13, 09:48 AM
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The side of the house that this foundation is on is the most exposed to weather. There are two downspout that direct water away from the house about six feet through 4" pipe under the lawn. The "waterproofing coating" is actually latex paint. Whoever sheetrocked the basement walls did so without building out from the foundation. so the foundation is part of the interior "design". The outside of the exposed foundation has not been painted or treated. I don't like the appearance of a painted foundation so I never painted it. Perhaps a couple more pictures would help to show the exterior and a crack in the foundation that may(?) play a part in this. I will take a couple more pictures and post them for you to see.
This definitely needs to be fixed before any flooring decisions can be made. Thanks.
 
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Old 01-20-13, 09:58 AM
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Yes... the inside surface is entirely exposed to the cold on the outside. There is another wall that is not having the save problems and I am guessing that is because it is several feet below grade and that the earth is acting as insulation? Temperature-wise, we are in the Northwest and it has been 25-45 degrees lately. How does heating affect the condensation? And I assume by the moisture behind the bookcase that I probably should not place items against that outside wall?
As for frost, I would doubt that as it isn't super cold. As far as the dirt, I see no evidence of anything "living" doing it.
 
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Old 01-20-13, 10:55 AM
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The pictures below:

One shows a view of the interior wall with the crack in the foundation. I am tending to think it doesn't come into play as I have not seen any changes in it in the 21 years we have lived here.

One shows a view of the foundation on the outside. The horizontal "line" on the foundation roughly represents the height of the basement concrete slab floor.

One shows a view of the lay of the land in the yard. The down spouts final exit is at the top of the rockery.

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Old 01-20-13, 12:04 PM
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Well you certainly have enough slope for drainage, as long as the water doesn't pool up against the other side of the house. If there is water seeping into the soil on the other side, it may be providing the pressure that is pushing that dirt up as described.

The term Relative Humidity (RH) describes the capacity of air to hold moisture. It varies with the amount of moisture in the air and the temperature of the air. Homes provide lots of moisture and when we add heat we look for 30% to 45% RH. As your 70 inside air drops in temperature its RH goes up. At the magic "dew point" the air will be at 100% RH and further cooling means condensation. 70 air at 40% RH has a dew point of about 45. An exposed concrete wall can easily reach that temperature, especially if the heat is blocked.

Temporary solution, keep the concrete warm. permanent solution, insulate the wall, inside or outside, so that the inside surface never drops below the dew point. Here is a RH calculator to play with: Temperature, Dewpoint, and Relative Humidity Calculator

It looks like you may want to peel that carpet back as well to see how much mold is under it, if any.

Bud
 
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Old 01-20-13, 12:14 PM
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The house on the other side is indeed higher than ours. The footing has weep holes that I would think relieve any pressure from under the slab (?).
So keeping the basement warmer will help the situation?
We do plan on pulling back the carpet to inspect as we would like some type of wood flooring or new carpet once we remedy the dirt and mold problem.
Will check out the calculator... thanks.
 
 

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