# Radon and french drains



## Easy Gibson (Dec 3, 2010)

Got a customer that has a half a basement they'd like to have finished. Basement gets small amounts of water as it's in a low laying area near a pond. Wanted to do the french drain into the existing sump pump, but there is a radon issue. They have a detection/fan system in place.
Does this completely kill the idea of the french drain? If so, is there anything else that can be done to divert water that I'm just not thinking of?

Figured I'd poll the audience here before I went to google. Figure one of the Jersey guys here have run into this.


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## mski (Apr 4, 2013)

Dont see a problem putting a french drain in. 
Most radon systems if put in after the house was built would be a passive sub slab depressurization system were the radon system pulls the air through the gravel base under the slab.
It's just a 3" pipe stuck into the slab, connected to a fan and exhausted to the exterior.

If you were to put in a french drain the radon system can be connected to it and the sump pump covered with a radon cover. 

One thing you should do after the french drain is put in is have the house/basement tested again for current radon levels. If the level is above 4 pico-curries additional mitigation by a EPA radon contractor would be needed. 
It's actually recommended by EPA that any basement that is altered with a system installed be tested before and after renovation.

In your contract and verbally tell your clients that a before and after radon tested is recommended by a certified tester before and after the renovation of the basement section. 
It's been a while since I did radon testing but I'd guess each test should be about $150.00 depending on the type of equipment the tester uses.


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## Flag ship (Nov 21, 2008)

Easy Gibson said:


> Got a customer that has a half a basement they'd like to have finished. Basement gets small amounts of water as it's in a low laying area near a pond. Wanted to do the french drain into the existing sump pump, but there is a radon issue. They have a detection/fan system in place.
> Does this completely kill the idea of the french drain? If so, is there anything else that can be done to divert water that I'm just not thinking of?
> 
> Figured I'd poll the audience here before I went to google. Figure one of the Jersey guys here have run into this.


 If they have a pit they most likely have a grid of pipe back to the sum pit now. If I was mine I would have a gravity drain out to daylight. Drain system grid inside under slab and out side with min 12 3/4 mod stone over the top off the tile
second yes you can do a french and not harm the radon collection. You have to get a foam tube (thats what it looks like) dont know the name any more and a specific calk (again it isnt calk but cant recall the name) You should alway retest after doing this type of work prior to construction just to be on the safe side. 

Look and see if they have an out side drain first check and see if the insdide is tied to it and if out to grade. If not connect the 2 and go to day light if grade let's you.
The second opt. of add. is lots of work and isn't as good imo.


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## Easy Gibson (Dec 3, 2010)

It's kind of a bizarre situation.

They have a well pump housed in a concrete room connected to the basement which has it's own drainage, but was for some reason poured higher than the basement floor itself. Even with that drainage it occasionally overflows into the main basement(lines are old and probably blocked by roots or something). The sump pump is a new addition and I didn't see any evidence of a system tied to the pit. It was simply at the low point in the floor.
Of course, this is supposed to be an econo job. Homeowners are selling in a month and are looking to get a little added value to the house by pouring a new level slab in half the basement and finishing a small rompus room or whatever for kids down there.

I'm guessing that this one isn't going to materialize.

Thanks for the replies. Will update.


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