Determining if a french drain will work or not?

[SmallTimeCountry]

I have the exact same problem. With every heavy rain, I end up with the corner of my basement damp and sometimes, noticeably wet. Above the area of the basement that's always wet, I have a large trex deck (approx. $16k worth) so tearing it out to do any extensive work is not even an option. The slope of the terrain underneath the deck is fairly flat.

My question and what I've been contemplating is clearing out the small amount of weeds, laying down a weed barrier, and putting down enough river rock to gradually slope away from the house, maybe a couple inches worth. The problem is I'm not sure if this is going to work. Please keep me and everyone else that may have a similar problem posted on your progress and results.

 

[toy]

If your guttering down spouts go into a pipe and the pipe is underground then I would pull the down spout out and measure how deep the pipe goes down before it turns to go around the foundation of your house and figure out where the pipe runs along your basement wall. Hopefully it will go as deep as the footer is. After you have done that get a garden hose and run water in the pipe and watch for it to come out where the discharge is so you will know if it is stopped up. If it is stopped up run a snake down it to try to unclog it. If you have a drain in the floor of your basement you would think that whoever built it would have put drain tile around the outside peremeter of the house. When I built my house I put pipe around the outside of the footer a little lower than the footer and put gravel around the pipe. I also put 2inch rock bed inside the walls of the basement and then put smaller gravel over that and then put a vapor barrier over that and then put in the steel and poured the basement slab, everyone said I would have a wet basement but I have never had any problems with it.

To be more inline with your situation when I built my lower garage when the footer was dug it filled up with water immediately and we couldn't do anything with it that way. I had the man that dug the footer set back from the footer and dig a ditch a little deeper than the footer and put in an 8 inch drain line around the garage site and filled the ditch with gravel and that did the trick{ I have a mountain behind my garage that was where the water was coming from] I haven't had any water problems from that but I do have some water that seeps under the doors when we have a blowing rain storm. I intend to address that problem by putting a little stoop over all of the garage doors especially the walk through door for a shelter for my dog when I am in the garage and he is laying at the door wanting in.

By the way the set back behind the garage is about 10 to 15 feet, glad I done it as I was building cheaper that way.

 

[NuBota]

My typical response to these type of questions is to attack the problem from the inside - an interior drain tile system and sump pump. I have suggested this to friends and co-workers dozens of times - after they look at me like I'm nuts - I convince them - they do it - and all swear by it afterward.

It seems counter intuitive and like too much mess and work, but it is not as bad as it seems and is pretty much guaranteed to resolve the issue. It is labor intensive, but relatively cheap and simple to do

Addressing the problem from the outside "may" work, depending on the situation - but if the problem is primarily ground water entering due to hydrostatic pressure - outside work may only provide temporary relief if any at all.

This was an excellent thread here about doing the interior system -

http://www.tractorbynet.com/forums/rural-living/72203-water-basement-help.html

the beauty is - you don't have to do the entire perimeter if the problem is confined to one area. And you can always "extend" the system later.

Anyway - if you think you can resolve the issue from the outside without major effort and expense, it is worth a shot. For me though, I wouldn't waste the effort unless the outside issue was blatantly obvious and simple to fix.

I just did this for the DW's 90 year old grandmother's house last summer - me and my two teenagers - 60' (entire front wall) - in two days - roughly $600 for pump, materials and equipment rental. I could have attempted to fix it from the
outside - because she had two huge, built-up flower beds across the front of the house that likely created and/or contributed to the issue. Fixing it there would have cost as much, if not more to deal with, taken more time, and still may not have worked.

Just my $.02 - biggest downside to the interior fix is there is no real use for the tractor......

 

[grossgary]

I'll try and get a picture.

The basement is buried for the most part. It's under the deck so hard to say and not sure how much water lies under there after a rain, I'll try to see.

One side of the house stays dry (it's 4 feet higher due to multi level layout and carpeted) the other takes on water in the far corner area.

rswyan - it's very simple - yes the land slopes down into my house where the leak is occurring. In other words as you walk AWAY from the wall of the house that leaks you're walking straight up a very steep grade, there's a mountain behind my house. So it's very easy to picture water running down towards the house where it's leaking. The ground is basically flat about 10 feet behind the house where the deck is before the steep slope begins. It's hard, terrible, mountain soil with not very thick grass, some exposed soil.

There's also a drainage cover at the landing of the outside stairs to the basement door so there's obviously something down there at the footer level.

The fact that the slightly higher side of the house doesn't take on water makes me wonder if it's a ground water/footer issue and a french drain isn't going to help?

dave - we're headed to millinocket first then bar harbor. i heard from someone else the black flies and other biting fun stuff are terrible last week. wanted to do some fishing, see a moose, Katahdin the first couple days, then down to bar harbor area for some bike rides and lobster.

 

[dave1949]

The fact that the slightly higher side of the house doesn't take on water makes me wonder if it's a ground water/footer issue and a french drain isn't going to help?

dave - we're headed to millinocket first then bar harbor. i heard from someone else the black flies and other biting fun stuff are terrible last week. wanted to do some fishing, see a moose, Katahdin the first couple days, then down to bar harbor area for some bike rides and lobster.

That sounds like a very challenging situation with 10' of flat then up a steep hill. Not a lot of room to work there with or without the deck. Given that, you might well want to look into an interior solution as described by Nubota . That is how lots of the wet basement fixing companies do it.

Our black flies have been gone for weeks, but the deer flies are more than making up for them You might get black flies too where you are headed further north. Those head nets you wear over a hat would be worth having along. They only cost about $3.50 each. You can get them at Walmarts and hardwares here in Maine. Cheap way to keep your blood and sanity. Deep Woods Off will repel black flies and mosquitos, and works some on deer fly.

I hope you see a moose, that's always iffy and takes some luck. They can be 20' in the woods and they just disappear since they blend in so well with tree trunks, etc.

If you are fishing inland lakes, this is a slow time of year. I think people fish deep in cold water for lake trout and land-locked salmon this time of year. Never got into Maine fishing, so take that for what it's worth .

Have fun whatever you do.
Dave.

 

[rswyan]

I'll try and get a picture.

That would be very good - just for everyone reading here to obtain a good understanding of the layout of the structure and terrain .... nothing like putting a set (or sets) of eyes on it.

The basement is buried for the most part. It's under the deck so hard to say .....

The basement actually goes under the deck - the deck goes over top of it ?

If so, what type of roof is on the basement under the deck ?

and not sure how much water lies under there after a rain, I'll try to see.

Yeah .... this ya gotta know .... to really understand what might or might not be occurring.

One side of the house stays dry (it's 4 feet higher due to multi level layout and carpeted) the other takes on water in the far corner area.

IC.

rswyan - it's very simple - yes the land slopes down into my house where the leak is occurring.

Yup .... figured it might be .....

In other words as you walk AWAY from the wall of the house that leaks you're walking straight up a very steep grade, there's a mountain behind my house.

Right.

So it's very easy to picture water running down towards the house where it's leaking.

Yup ....... exaaactly ! :thumbsup:

The ground is basically flat about 10 feet behind the house where the deck is before the steep slope begins.

IC.

The point just before the slope begins is where you need to have the diversion ditch or channel.

I'm assuming a bit here - primarily that when there is precipitation, or at least heavy rain, that there is some surface runoff that coming down that slope.

There is undoubtedly ground, or subsurface, water percolating down the mountain as well.

The diversion ditch should be capable of collecting all the flow that comes down on the surface and then channeling it away from the foundation. It could be as simple as a small ditch a couple of inches deep and maybe foot wide (or even less) - whatever it takes to catch the surface flow. It could be planted in grass .... or covered with washed gravel (no fines) and/or rip-rap.

I would suggest placing or burying some heavy gauge plastic (10 mil poly or better) at the bottom for a barrier to prevent the water from seeping down into the soil. Make it wider than the ditch itself and tie it in by covering the edges with several inches of the existing soil. Then cover the center with either topsoil or gravel.

You might wish to make it long enough to completely divert the water away from the foundation and carry it off to where it is no longer a problem - or you might want to route the ditch (and the surface runoff) into a catch-basin (large or small, depending on your needs) and then use hard pipe to carry it to wherever it needs to go (the creek ?)

This ditch could be directly over any french drain system you install - but in no case should you allow the surface runoff to go into the french drain - handle it separately - you don't want more water going into the ground anywhere near, or upslope from, the foundation.

It's hard, terrible, mountain soil with not very thick grass, some exposed soil.

Lots of clay ?

There's also a drainage cover at the landing of the outside stairs to the basement door so there's obviously something down there at the footer level.

You hope ......

Never underestimate the ability of people to be completely stupid and do things which make absolutely no sense whatsoever, and which border on being criminal.

Stuff like placing a drain cover ...... which goes nowhere ..... (not connected to piping) .... not saying that's what you have, but it ain't outta the realm of possibility ....

The fact that the slightly higher side of the house doesn't take on water makes me wonder if it's a ground water/footer issue and a french drain isn't going to help?

Ground water is exactly what a french drain is designed to solve

My upper front yard is a field about an acre plus which is separate from the lower front by my driveway. The grade of the land is from the upper yard to the lower one. The driveway is roughly 12" - 18" above lowest part of the upper yard - thereby forming a barrier to surface runoff.

When it rained water would pool at the lowest points of the upper yard and it would stay wet for days .... and days ........ and days .... couldn't get into mow it without making a terrible mess and rutting it all up.

I dug roughly 250' of trench, 3' or so deep and installed a french drain using washed 57 gravel (about 18" deep) and 4" perforated pipe (with soil sock) placed near the bottom of the trench .... and then routed that to a catch basin which had a culvert that went under the driveway and emptied out in the lower yard. The trench was then covered with topsoil and planted in grass.

The result is that the upper yard no longer holds water - within 24 hours after a heavy rain there is no standing water, and within a couple of days (of dry weather) I can take the tractor on it.

On the french drain you are going to need to go deep enough to catch the majority of the subsurface water coming down the mountain ..... I would think that ideally it would be below the grade of your foundation.

It should be placed out away from the foundation some distance (out past the deck sounds like the place to me) - so that it both intercepts the flow of subsurface water coming down the mountain .... and draws water away from the foundation.

It should be capped well below the surface with an imperious material (say, clay) that will prevent surface runoff from finding it's way down there.

You might want to have a look at the following article, as well as the other articles on that site:

The French Drain: Theory, Application & Practice

 

[NuBota]

I'll try and get a picture.

The basement is buried for the most part. It's under the deck so hard to say and not sure how much water lies under there after a rain, I'll try to see.

One side of the house stays dry (it's 4 feet higher due to multi level layout and carpeted) the other takes on water in the far corner area.

rswyan - it's very simple - yes the land slopes down into my house where the leak is occurring. In other words as you walk AWAY from the wall of the house that leaks you're walking straight up a very steep grade, there's a mountain behind my house. So it's very easy to picture water running down towards the house where it's leaking. The ground is basically flat about 10 feet behind the house where the deck is before the steep slope begins. It's hard, terrible, mountain soil with not very thick grass, some exposed soil.

There's also a drainage cover at the landing of the outside stairs to the basement door so there's obviously something down there at the footer level.

The fact that the slightly higher side of the house doesn't take on water makes me wonder if it's a ground water/footer issue and a french drain isn't going to help?

dave - we're headed to millinocket first then bar harbor. i heard from someone else the black flies and other biting fun stuff are terrible last week. wanted to do some fishing, see a moose, Katahdin the first couple days, then down to bar harbor area for some bike rides and lobster.

I'm no geologist - but I would bet you are dealing with hydrostatic pressure forcing water in from beneath the slab and footing. Given what you describe, unless the water comes down the mountain and accumulates in your backyard, saturating it - I would doubt the surface runoff is your issue. Especially if the surface is hard - I would assume the majority would just run on past your house and continue down hill. If the runoff was the problem I would expect that walls in the affected area to be damp/seeping as well - depending whether they are block or poured. If the breach is only at the cove joint (where slab meets wall) then most likely it is due to hydrostatic pressure.

 

[rswyan]

My typical response to these type of questions is to attack the problem from the inside - an interior drain tile system and sump pump.

There's one big problem with sump pumps ..... they depend on electricity to remove the water.

Little story: Young couple bought a house up the street from me .... they ended up breaking up, getting a divorce, and moved out of the home.

Bank repo'ed it and it sat empty for better than a year ..... maybe two ....

My nephew was looking to buy and decided one day to stop by and have look at the place .... discovered that the house was actually unlocked, so he went in and had a look around ..... looked pretty good for a starter home ...... but before he left he decided to have a look at the basement ....

What he found when he opened the door down to the basement was about 5' or 6' of standing water ..... the bank, in it's infinite wisdom, had not bothered to have the electric service turned on after the former owners left .....

Eventually the house was sold ..... and had to be completely gutted, with all drywall removed and remediation done to handle all the black mold that was now inside the walls ......

No electric = no working sump pump .....

..... planning on taking a vacation ? .... hope that sump pump has an alarm on it and someone is monitoring it while you are gone ....

Addressing the problem from the outside "may" work, depending on the situation - but if the problem is primarily ground water entering due to hydrostatic pressure - outside work may only provide temporary relief if any at all.

I would say that the above is only true if the outside drainage system is done improperly ...... like I said, there's no telling how stupid people (including some contractors) can be .....

If the outside drainage is not done correctly, yeah you will probably eventually have problems .... so just do it correctly .....

Anyway - if you think you can resolve the issue from the outside without major effort and expense, it is worth a shot.

As was mentioned in the thread you referenced, it is the difference between addressing the consequence of a problem, or the actual cause or source of the problem.

For me though, I wouldn't waste the effort unless the outside issue was blatantly obvious and simple to fix.

Sounds to me the issue is blatantly obvious - the guys foundation is butted up against a mountain ..... given gravity, water will flow downhill ....

Ever been driving down the highway in hilly terrain and seen water seeping (or even shooting) out of face of cuts into the terrain ?

This ain't a big mystery or rocket science .... it's simple physics.

Fixing it there would have cost as much, if not more to deal with, taken more time, and still may not have worked.

I'd disagree - at least to this extent - done correctly, it absolutely would have worked ..... but that's just my opinion.

.... biggest downside to the interior fix is there is no real use for the tractor......

Well, our first home had an interior system ...... the concrete floor was cut out and removed along perimeter next to the walls, gravel and drain tile installed, run to a sump that was installed (with pump) and the first course of block above the slab was drilled, and then an overlayment of mortar was placed over the first course of block .... so you couldn't see the holes .... probably using some type of screen or lath .....

While was no standing water, the basement was always damp and smelled musty .....

This "system" was installed before we bought the home .... being a first time home buyer I didn't know any better ......

The real problem(s) ?

1. The gutter downspouts didn't go anywhere - they just dumped out right near the foundation.

2. The yard on one side of the house had a slight slope towards the house.

Two problems that could have been relatively easy to fix ..... instead the former owner paid probably not an insignificant sum to have someone come in and fix the consequence, rather than the actual cause.

 

[rjkobbeman]

A little off topic, but not too far...

In regards to sump pumps and the damage caused if electricity goes off for whatever reason...

There are emergency backup pumps out there that work on water flow. You hook up your water line to the pump and the water flow draws water from the sump.

Inefficient? Yes. However it works. Who cares how much water you waste as long as your sump stays dry? It is connected so it only comes on if water gets above the normal electric sump pump operation.

Of course, if you get your water from a well (where you have to have electricity to have water pressure) then this does not work for you.

 

[rswyan]

Anyways, there should be a drain pipe that runs all the way around your foundation at the footer level. From the floor drain and gutter drains you describe, I would guess they tie into that foundation drain pipe.

The above may well be true - and if it is in fact the case, it's probably the absolute worst thing that could have been done - the contractor that did it ought to be shot from guns.

Think about it: In essence, one is taking surface water (which is nowhere near the foundations when it arrives on the roof), and could be easily moved away from the structure with a hard pipe ..... and then routing that water down into what I would assume to be a perforated pipe (otherwise what would be the point ?) around the foundation ......

My guess would be that every hole in that perforated pipe does not have a one-way valve on it ......