damp basement in new home

My wife and I moved into a newly constructed home in an older development. On the west side of our property runs a small stream (about 50 feet from our house). The house is in an area that is known for having a high water table. We have a poured concrete basement and a sump pump. We think we have a french drain on the outside perimeter of the house, but are not 100% sure. I believe that the outlet for the outside french drain leads into the sump pump (inside the basement). In the center of our basement, near the load-bearing beams, there is quite a bit of dampness.
We have had a couple of waterproofers come in to give an estimate and they've both suggested installing an internal french drain and have quoted about $7500. I don't see how that is going to alleviate our problem considering we already have an external french drain. Am I right in that assumption?
Does anybody have any ideas or suggestions? Thanks in advance! Kartik
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It sounds possible your builder failed in two areas. Under the concrete floor, the space between the footings should be filled with clear washed gravel 6 to 8 inches thick. This would provide an area for any moisture under the floor to travel to the sump for pumping out, eliminating any need for internal French drains, as you may have a small spring under the floor. Secondly, many codes now require a minimum 6 mil thick poly sheet over the gravel with the concrete poured over the plastic sheet to reduce dampness transmitting from the gravel layer up into the concrete floor.
If your home is that new, you may be able to claim through the warranty, also you may be able to find the builder (or at the building department) and check what the plans called for although the builder may have taken shortcuts in the basement despite what the plans show.

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In addition to what EXT suggests, always look at the obvious, cheap solutions first- people spend small fortunes on these issues. Look at your gutters/ leaders; see if they are carrying water away and downhill from foundation. Also look at what is uphill from your foundation- possibly water is running down toward you which could be diverted, though presumably your external french drain is designed to handle this. Realistically, with high water table, this may be a hard problem to fix perfectly. The builder should have addressed it.
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Thank you for your responses. We live at the bottom of a hill, so there is a very high likelihood of water carrying towards us. The gutters are carrying water away from the house through underground piping that leads to a pit at the back of the house that is supposedly about 12 feet deep.
The problem is that the builder is completely inaccessible - he is a relatively small builder although he has built some rather large condos in the area. He doesn't give out his phone number and having his realtor act as a go-between to get things fixed (such as a blown compressor in our AC unit at the beginning of the summer) just takes such a long time. I just get the feeling that it will take more time and money (in terms of court fees etc) to get him to fix things. I can only guess how he has constructed things...
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snipped-for-privacy@gmail.com wrote:
<snip>

Seems to me you have bought into a nightmare of future problems. Given that situation, I would put the place on the market and try to find something where some peace and serenity are possible as well as a warranty. The proximity to running water alone could be a disaster ready to pop. Have a hard look at the reasons you are staying there and start thinking more pragmatically about your future. Good luck.
Joe
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Would a "curtain drain" be helpful, since we live towards the bottom of the hill?
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Certain water issues must be in the real estate disclosure depending on the local verbage. Even if sold he could still be held liable for the repair.

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