# Walls on top of interior french drains in basement?



## canoes (Sep 30, 2011)

I bought a house in which the basement is built in the side of a steep hill with the back wall about 10-12 feet of concrete and the front a walk out. A previous owner had put in a french drain system and it seems to be working well. I want to finish the front half of the basement but am concerned about messing up the system. Two questions:

1. The concrete over the french drain is not completely level with rest of floor. What precautions does contractor need to take when leveling it (to keep gap between floor and wall?

2. The walls would normally be built where french drains are, I think Is that OK? 

I'm not sure how familiar contractors here are with them-a couple who have done other work seemed not to know.

Thanks. If this needs to go in another forum, please advise. This seemed to have current postings.


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## canoes (Sep 30, 2011)

Just checking to see if any responses. Was I not clear on question? Know of anyone who could tell me? I think the framing would go around perimeter of basement which would be directly over the drains and am just not sure if that's OK.


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## SunnyRF (Oct 3, 2011)

The purpose of a French drain is to gather water, and displace it somewhere else.
Whenever possible you do not want water near your foundation! 
Those are two basics. If you can understand those, you can't answer that question.


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## SunnyRF (Oct 3, 2011)

I meant to say then you "can" answer that question. 
It is difficult to answer yes or no. Because many other factors can come into a affect.


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## jomama45 (Nov 13, 2008)

Take a picture or two of it and post it here and you'll be more likely to get help.


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## canoes (Sep 30, 2011)

In this type french drain, about a foot of concrete around the inside perimeter of the basement was dug up, the french drain (and probably gravel around it) installed and another layer of concrete installed on top. Some have sump pumps connected to the system but this one doesn't doesn't prob because of the slope. 

It is not exactly this system, but it looks similar in that there is a piece between the floor and the wall and there is a layer of concrete covering it.
http://www.homeservicessouthwest.com/basement-waterproofing/foundation-waterproofing.html

The patch layer of concrete over the drains isn't level with the main part of the basement and I've no idea how thick it is. It was done 2 owners ago.

The contractors around here don't seem very familiar with it.

Thanks


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## jomama45 (Nov 13, 2008)

Considering the walls will be non-load bearing, I don't see the weight to be any issue at all. I would, however, be careful not to drill any unnecessary holes through the retro-fit tile. You could probe around with a hammer drill and small bit first to verify how wide the channel stands off of the wall.


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## canoes (Sep 30, 2011)

Thanks for the feedback. If the system plugs up, do you know if they just scope it from one corner? Have to dig up part of it again? Just want to know if I should keep an area without the walls on top of them.


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## canoes (Sep 30, 2011)

*update*

I just thought I'd post a followup note in case someone has a similar question in the future. I found the company that installed it, b-dry, and walls can be built on top of the drain. It cannot be nailed into so liquid nails have to be used over the french drains.


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