I have a French drain with a sump pump in my basement.
For 11 years I NEVER got any water down in my basement, the drain took care
Now suddenly in the past 2 years I have had 3 major floods (including this
morning) where the water has soaked /ruined my carpets in the basement.
Any ideas why the French drain would suddenly stop working. The Sump Pump is
working fine. It is turning on and off and ejecting the gathered water from
the sump well.
Would blockages/debris that fell into the drain area around the perimeter of
my basement wall be the culprit?
Or could it be a case of the ground outside being so saturated the water has
nowhere else to go but in my walls/French drain and the French drain can not
handle the capacity of water coming in.
I had home construction done (new siding, windows, doors, deck) about 2
years ago. Could they have damaged something? I have looked all around the
areas that they added new doors, windows, deck, ect.. and I can not find any
water seeping in.
By the way, I am in NJ where we were hit with 7-10 inches of rain in the
last 15-20 hours and a state of emergency was declared.
Is this "french drain" installed inside the foundation under the concrete
floor? Or is it a perimeter drain around outside the foundation wall? If it
is the first, your water may be coming in through the wall or wall/floor
seam. If it is the latter, it may be water table coming up through the
ground under the floor.
If you have both systems, you should have no problems.
I don't know if it is an actual "French Drain"
It is on the INSIDE perimeter of the basement and has a concrete "channel "
that is about 1+ 1/2 inches high that collects the water and routes it
around the basement perimeter to the sump well.
The house is about 60 + years old.
Also, I cannot find any sign of wetness on my walls, this is very strange.
Currently I am trying to get behind my walls and trying to brush/vacuum out
any debris in the channel.
I live in northern NJ, too, and have an outside French drain that normally
carries away water that runs down the back yard towards the house (the yard
was mis-graded sometime in the early 1920s, no way to regrade it now). The
drain forms a "U" around the whole back and sides of the house and empties
down the driveway where the water flows into the street.
This neat little drain system works great in normal rainstorms, but
yesterday sure wasn't normal. We got 7.06 inches of rain in less than 18
hours and it was still raining this morning at 11:30.
Here's what happens to my drain: the gravel-filled trench the perfed pipe is
buried in fills up because the pipe cannot take all the water away fast
enough, even though it's a 6-inch pipe. When this happens, water flows over
the top of the trench and soaks the narrow strip of ground behind the trench
and eventually seeps into the basement.
Yesterday, it got so deep in one spot, an inside corner next to a door, that
the water started flowing under the threshold of the door and pouring into
the basement. Fortunately, it's a short trip to the basement drain, which
was able to handle the flow easily, so not much got damaged. The only other
time that happened was in 1999 during Hurricane Floyd.
So my guess is that yesterday your system could not handle all the water and
I had a problem with a true french drain system that wasn't working. I
dug it up and found there was no sock on the 6" pipe. Every foot of
that pipe was absolutely filled with sand and stuff from the dirt. It
was totally filled up and useless. Even the pipe that went out into the
yard was filled.
French drain 6" pipe is slotted, where regular pipe is not. Slotted
pipe is only sold with a fabric sock around it by outlets that know what
they are doing, such has Home Depot. I saw the same thing in a cash and
carry builder supply here with a sock. I've seen descriptions of a
french drain field on the internet without a sock. Every time I see it
that way I think of my filled-up pipe.
The rest of what I could tell you is all personal-experience stuff.
Your situation could be so much different, as some of the other posts
have pointed out. In my unusual case, there apparently had been a
ravine between the houses when they were built that was filled in with a
sand or gravel filler. We are on the downhill side of the resultant
slope. When it rains in the neighbor's yard, it settles down and fills
in the sand and gravel, all the way under the yards to my house. When
they built an addition on to our house some years ago, they put the new
brick corner right on top of one of the main runs for this groundwater
It caused no problem, but as I was waterproofing my foundation, I struck
water. Every time I dug more than two feet deep, I had water in the
hole. I started digging in other places to get the flow of the water by
the various levels I found, usually two feet below the surface.
To fix it, I hand-dug a 6' deep trench 50' long and 2' wide. As I cut,
I found the top 6-12 inches were dirt; below that I found this
construction filler sand. My moisture meter found moisture in the dirt,
but not in the sand, being above the water level. I concluded the dry
reading showed that the sand could easily transport the water underground.
Once dug, I lined it with a roll of 6 mil plastic. At the bottom, I
laid 6" french drain piping in a sock. At the end of the run, I put
regular 6" pipe out to the street. I got permission from the city to
put a hole in the curb, where I put a drain piece.
Technically, what I did wasn't a french drain. Since I already had sand
and gravel in the ground, I didn't have to change it, saving me a
fortune in labor and expense. Also, a real french drain is to catch
rainwater running downhill on the surface of the ground, eventually
seeping in. Since my groundwater was always more than two feet below
the surface, it was not your typical french drain, especially since the
pipe was six feet deep. And of course my 6 mil vinyl sheet along the
trench blocked a potential of six feet of water seeping under my house.
After a major rain, my drain will run for up to six days, hopefully
indicating that the system works.
I also ran my gutters into it. A sewer guy from the city said to always
use "Y" pieces to feed other runs into it, not "T"s.
One run was from our small basement. It was slimey due to no
waterproofing on the foundation. Water was always standing and the
former owner had plywood on concrete blocks set up to do her laundry.
Six months after waterproofing, I had it bone-dry.
Since I am 72 and retired, I could take the six months necessary to do
the project. If I had a contractor do it, it would have cost $5-10,000.
Needless to say, it was good exercise.
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