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crazydrum

05:38PM | 09/23/03
Member Since: 09/22/03
3 lifetime posts
Bvbasement
Finishing Basements with high water table underneath ?
WHAT DO i DO TO MAKE an existing basement with a high water table last a lifetime ?
There is a high water table underneath a existing basement which has the proper size sump and french drain with pebbles, rocks underneath the floor, how would you finish a basement.

The pump pumps continuous EVERY 20 minutes during about 60% of the year until the water table recedes in Delaware County ( near Philadelphia), Pennsylvania. It is
high altitude but sits in a little valley. The poured concrete walls are painted with DryLoc and the floating poured concrete floor is not coated. The edges of the floor/wall are stuffed with the expansion joint when it was built about 11 years ago and this expansion joint was removed in various spots due to power failures when the basement flooded with 4" of water and we had to get the water out to drain into the french drain system. This has happened about 4 times. Also, the drainage around the house is excellent except for hurricanes , Hurricane Floyd , and every winter the melting of snow, ice which builds up along the foundation and melts in spring and pours over the walls of the basement.This is minumum water into the basement over the floor joists and top of the basement concrete walls but not through the walls.

What should I do ? Do I remove the expansion joint at the wall/floor joint and allow more moisture to enter or do I push the joint down ( recess it) and drill holes say every 1 ft to collect it and drain it to the french drain to minimize moisture entering the basement air. Also, DO I install this vapor barrier also or leave it out ?
ALSO, DO i INSULATE THE WALLS or will it cause problems ?

Also, along the permiter of the floor/wall where the expansion joint has been removed, there is efflorensce ( white dust ) at the opening. We are about to have the basement finished and the studs just started and wanted any ideas since no one has the right answer.
Please any suggestions.....

plumber Tom

02:33PM | 09/24/03
Member Since: 05/10/03
801 lifetime posts
Are you sure there is perforated piping that leads to the sump pit? and not the gap in the floating slab that you are calling the french drain? Do you have a lifetime guarantee against water on your basement floor? Waterproofing companies will offer this, commonly to "sell" their job to get you to waterproof all 4 walls. Don't drill holes in poured concrete walls. That's only feasible in cinderblock walls, where the water can enter the hollow block cavity, then drain into the system. The water will actually run up from the footer, and flow out of the gap, level with the finished floor. You might want to invest in a battery operated back-up sump pump in case of a power failure. It can be installed with a tee, "piggybacked" on top of your existing pump.

crazydrum

03:24PM | 09/24/03
Member Since: 09/22/03
3 lifetime posts
Plumber Tom,
ANSWER TO YOUR QUESTIONS
1.Yes, I took pictures of the perferated 4" piping underneath the basement floor prior to the concrete pour of the floor 11 years ago over this french drain system into the sump which has a pump.You can see the 4"diameter perferated pipe which is attached to the sump visually and you watch the water drian into the sumps .
2.There was no waterproofing company involved with the application of the DRY-LOC on the walls. We did IT ourselves.
3. I do not WANT to drill through concrete but drill through the expansion foam joint ( about 1/2-3/4" which is still along the permiter where the wall/floor meet and also push it down 1/2 " RECESSION to be able to collect water if the snow melts over the basement wall and can collect and drain into the french drain below THROUGH THE PROPOSED HOLES.
4. Yes, I am investing in a back-up battery pump.
Thanks.....

plumber Tom

05:26PM | 09/24/03
Member Since: 05/10/03
801 lifetime posts
OK since your a DIY'r, you might wan't to try a product called mirror drain, that you can install, by placing it in the gap, and nail it to the wall. It's basically a big sheet of ABS plastic, that has small "checkered" squares. You can cut the sheet, oh say 5 to 6 squares high, depending on the size you need. It's available where waterproofing pipe and supplies are sold. Any water coming in, would be channeled behind the mirror drain, and into the system. I would think that would be better then the wet expansion joint. It's nice to hear your builder took the extra step to install a system, while the house was still under construction. We used to do houses in Mullica Hill, NJ. Just after the poured concrete walls were cured, we would go in and install a french drain system, and Radon Crocks. it was so much easier because there was no concrete to jackhammer, and the soil in that area was sand. Then the builder would pour the floater. You sound like your on the right track, so best of luck with the new basement...........Tom

Glenn Good

03:25PM | 09/25/03
Member Since: 09/10/03
314 lifetime posts
I believe the product Plumber Tom is talking about is actually called MiraDrain. Here is a link to their web site: http://www.triumphgeo.com/products/miradri.html. I have used this product before and it is very good (but it is normally applied to the exterior side of the wall in conjunction with waterproofing). In your case however if you remove the expansion material altogether and replace it with MiraDrain (or any other porous filler material), it will allow the water to drain down to the French drain. I think you will find the disadvantage of MiraDrain is that it comes in rolls that are much larger than you will require. (Thus more waste and expense)

You could also just drill 1/2" holes down through the expansion joint about every 12" to allow any water to drain into the French drain system.

One disadvantage to these solutions is that they open up a potential entrance for insects and possible water intrusion should the sump pump fail or the drain lines become clogged.

Glenn www.consultationdirect.com

plumber Tom

03:54PM | 09/25/03
Member Since: 05/10/03
801 lifetime posts
Thanks Glen. Never saw the shipping label, that's what we alway's called the miradrain. I was close though LOL.

crazydrum

05:54PM | 09/25/03
Member Since: 09/22/03
3 lifetime posts
Thanks plumber TOm and Glenn Good.

The only two other questions I have is will 1.I have mold problems in the future ?
Is it better to rip the expansion joint out and install this Miri-Dri or seal/caulk the wall/floor seam over the expansion joint and hope the water evaporates from the Winter Spring melts annualy with water flowing over the basement concrete walls .
2. Should I install insulation in the walls or should I not DUE TO THE POSSIBLE MOISTURE from the walls . The gameplan now is to install a high mil vapor barrier with insulation R11. ANY COMMENTS !!
Thanks to everyone .....

Glenn Good

06:26PM | 09/25/03
Member Since: 09/10/03
314 lifetime posts
My recommendation would have to be NOT to finish the walls at all until the water infiltration problem is corrected. You do not want water getting into the basement at all, even if it is only once a year. If you do not stop this water infiltration you are only asking for additional problems down the road. You may need to install flashing and/or a good quality sealant outside to prevent the water from the snow melt from getting over the foundation wall.

If you do build the finished wall and water gets behind it you could end up with a mold problem.

I would not wait for the water that does get in to evaporate on its own from the basement floor. You could always cut in a small trench around the perimeter of the slab to divert the water to the sump pump or at least remove the top of the expansion joint and then seal over it to create a small trench (if it will be large enough to handle the water volume) to divert the water.

If you do not use the drainage holes or MiraDrain I would also suggest you slope whatever you do toward the sump pit.

Glenn www.consultationdirect.com

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