Wet Crawlspace

[Clare McCall]

I bought a house with a crawlspace. There is a sump pump located in the concrete lined pit where the lowboy water heater sits. There is also one with a collection area below a room on the lower level of the home. Although it was not disclosed to me prior to purchase, I have been told that a French drain system exists. Recently, we had a record snowfall followed by several inches of rain. The sump pump got hung up so both collection areas filled with water. That situation has been corrected and all collected water was discharged. The remaining problem is that the crawlspace floor is dirt and that dirt is wet. Not damp, wet. I have a lot of questions, but my primary concerns are: If I have a french drain that is not working properly, how do I fix it. And two, how do I dry that area out? We have expansive soils here. I’m very worried about the foundation. Any help will be sincerely appreciated. Thank you.

[John Aldrich1Participant]

Truby, the wet crawl space condition that you have described is a very serious problem, and must be remedied immediatly. The “stachybotrys” mold that proliferates in wet areas poses a serious health threat to you and your family.

>If I have a french drain that is not working properly, how do I fix it?<

It is impossible to give guidance on how to “fix” the french drain without knowing exactly the design, and the materials used in its construction. Typically, most french drains are impossible to access for cleaning, and so replacement is your only option. An excellent product for use as a french drain is “Advan-Edge” made by Advanced Drainage Systems, Inc. This is a gravelless product, actually a flat pipe that is covered with a geotextile fabric to prevent siltation. You can see this product on the ADS website. http://www.ads-pipe.com/us/en/products/advanEdge.shtml

>And two, how do I dry that area out? <

A crawl space ventilation system must be installed. Probably the use of electric fans must be employed to dry out the crawl space. I recommend that the ventilation system be permanently installed to prevent the moisture level from ever rising to the point where the Stachybotrys mold can exist. To find out more about this dangerous mold, and how to eliminate it, go to http://gcrc.meds.cwru.edu/stachy/

» This message has been edited by John Aldrich on 29 May 2003

[nicktheplumberParticipant]

You describe REALLY wet (not just “damp”) basement soil. As JA wrote, that is a BIG problem. A properly designed perimeter foundation drainage system should divert all water in the soil outside the foundation away from the foundation and basement area. The fact that you have mud under your house indicates at least one of two things: 1) you do NOT have an adequate perimeter drainage system; and/or 2) there is a spring under your house. Both of these conditions are fixable, though the latter requires a very complicated and expensive solution.

You have good reason to worry about your foundation. Hydrostatic pressure can ruin your foundation in short order. You describe snow in your location. That means freezing, and freezing plus water infiltration is a very distructive combination.

NtP

[TrubyParticipant]

John and Nick: Thank you both so very much for your input. Actually, I spent some time in the catastrophe clean up business and am quite familiar with the risks related to mold. I spoke with a long time associate who is a soils engineer who was able to give me some insight with regard to our soils. So, I set up fans and ensured cross ventilation. The soil has dryed out considerably in the past few days. If that does not dry it enough, I will rent some high volume dehumidifiers. He also explained how foundations are built in this area to aleviate some of the concerns you mentioned, such as hydrostatic pressure. I’m still concerned because I know the neighbors have similar issues. Frankly, I think this all goes back to the developer in 1986. I’m going to visit them and try to locate the blueprints. In the meantime, I am suspicious that there are some reverse drainage problems that could be covered up by landscaping. So, I guess I’ll put on my landscaper hat and see what I can find. At least for now, I feel like I’m on a better track, in large part to the advice you have so kindly taken the time to provide me with. Best wishes to both of you in all that you do. Thank you very much. Tanya.

---

Tanya Ruby

[nicktheplumberParticipant]

---

He also explained how foundations are built in this area to aleviate some of the concerns you mentioned, such as hydrostatic pressure. . Thank you very much. Tanya.

---

In general, foundations are built to universal standards: concrete mixture, the footing and wall dimensions, depth of placement, type and location of rebar, vapor barriers, and sill attachment specifications, etc. Even the best constructed perimeter foundation will fail under the assault of soil water infiltration and pressure. So besides proper foundation construction, proper soil grading and a perimeter drain system are essential to keep water from doing harm. Assuming your foundation contractor built everything to specs, you still have a problem, and that problem is either grading/drainage, or both. (and don’t forget simple things like faulty roof drainage). The only other problem when everything else is built correctly is a spring running under the house…and THAT is a gigantic headache to fix.

NtP

[Author]

Posts