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Water Seepage Basement Floor- Interior or Exterior Drain??

Posted by kimhoj (My Page) on
Wed, Sep 25, 13 at 19:15

I posted an earlier question regarding my basement problems and Worthy and fellow contributors did an AWESOME job answering the questions so a BIG THANK YOU!!

I was almost 100% prepared to proceed with an exterior drain system and then I noticed that there was mold and water underneath the temporary carpet tiles I placed down on the concrete floor- these carpet tiles have a rubberized backing.

The odd thing was that not all the carpet tiles were affected and the ones affected were not close to the exterior walls that typically have the leakage problems.

The carpet tiles affected seem to be located in the lowest part of the basement floor (the floor is not level- some parts are lower than others).

So my questions are:

1. How can I tell where the moisture is coming from? Condensation from the high humidity in the basement air versus water seepage through the basement floor?

I have a dehumidifier in the basement so if I run this and the problem still occurs, then should I assume there is still water seepage through the floor?

Can I do the "plastic on the concrete" test and see if there is moisture accumulation underneath the plastic? Would this help determine if there is water seepage problems through the concrete floor?

2. IF THERE IS A WATER SEEPAGE PROBLEM THROUGH THE FLOOR, which system BEST deals with this problem? An Exterior or Interior System? From the "original basement waterproofing handbook" the author suggested that an exterior system CANNOT deal with water seepage through the floor and only an Interior system can only deal with this.

IS this true and Why? If not true, can an exterior drain system prevent water seepage through the basement floor?

Thanks for this awesome forum!!


Follow-Up Postings:

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RE: Water Seepage Basement Floor- Interior or Exterior Drain??

Tiles or carpet with rubber backing or vinyl flooring are about the worst things to put on a basement floor. There is a constant vapour drive upward. Normally, that vapour is dispersed in the air and noticed as high humidity. But when you put those impermeable materials on the floor, the vapour is trapped and may condense into liquid water. And then run and collect in the lowest spots.

A dehumidifier is necessary in most climates to keep the relative humidity (rh) below 50%. Be sure to keep yours running.

If, with the tiles gone and the rh controlled, you're still getting water accumulation, it may be from the leaky walls. And even if the water comes up through the floor, it may simply be from water accumulating on the walls with no place to go or overwhelming the ability of the weepers to drain it. For instance, during heavy storms a homebuyer of mine complained of water running under the basement floor. You could hear it and actually see it around the basement drains. Turns out the source was the downspouts. The water ran down the foundation wall and accumulated in the five-inch gravel bed under the concrete floors. Since then, I always run the downspouts into underground drain pipes running far out into the yard.

The plastic on concrete test has long been outmoded by moisture meters. You're almost always going to get moisture under the plastic because of moisture drive.

This post was edited by worthy on Thu, Sep 26, 13 at 18:32


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