# Please Help Me With This French Drain System!



## coderguy (Jan 10, 2011)

Hello everyone! Coming upon my first spring project. Money set aside; plans to have a trench digging party; etc. (Yes, diggers hotline stuff all handled!)

So I need some help! Let me apologize up front for this being soooo long.

If you haven't followed my other posts; the short of it is: I have a lot of water in my basement. It is being mitigated by a drain at the bottom of the bilco stairs, running into a sump pump. But the stairs are a waterfall and the walls look horrible and obviously (block foundation), filled with water.

I need to address the water problem from multiple angles. I started by adding gutters to the garage that drain back to the alley, repairing gutters on the house, and extending the front downspouts.

A member on here came out to my house (very kindly and I thank him for it); and walked through some of my problems with me. He suggested a french drain wrapping from the background to a dry well at the front.

I'll lay out my plan, then my questions, then share the drawing...

1) Test drywell by digging one with a post hole digger and measuring water drainage.
2) Mark out yard for digging.
3) Dig a huge trench 
4) Start temporary laying pipe to work on making sure it will flow at 1 degree downward all the way around
5) Remove pipe.
6) add landscape felt.
7) add pea gravel.
8) add pipe
9) add pea gravel
10) wrap landscape felt.
11) Add some soil. (??)
12) add landscape felt (???)
13) More soil.
14) Sod.

1) How deep do I need to go?
2) How wide? (easydigging.com says 8,10, or 12)
3) How far does it need to be away from the foundation?
4) Can I run a solid pipe in parallell for a downspout, or could I connect the downspout into the french drain (research says that is a BAD IDEA). Would like to get off the city lateral (before they force me anyway)
5) I should use solid perforated pipe, holes down? Will make getting the angle of descent easier?
6) Most importantly; is all this effort worth it. I don't mean to question Joe at all... but if I need to dig out the house by hand (can't get digger into yard) to put a foundation drain in; I will. Would prefer not to?

Extra, I only have 30 to 36 inches of space to work with between the houses... my neighbor put his new sidewalk ON TOP OF his old one; and yes it is angled away from his house...

Future plans include a retaining wall in front of the garage (to allow leveling of the grade; and then a patio on the level grade.

(Edit: Link to my showcase thread: http://www.diychatroom.com/f49/526-lincoln-victorian-aka-new-money-pit-99484/index3/#post873071 )

Here is the drawing, it's very big...


----------



## joecaption (Nov 30, 2011)

http://www.easydigging.com/Drainage/installation_french_drain.html


----------



## CplDevilDog (Mar 18, 2009)

Make sure you calculate the proper size for your dry wells or you'll just be making a lake in the yard. If you can't get the volume (believe me, they can be *huge* depending on your rainfall avg.) arrange for an overflow to daylight. The dry well will then handle smaller showers but if you get a real "goose drownder" the water will have somewhere to go.


http://www.phillywatersheds.org/whats_in_it_for_you/residents/dry-well-sizing-chart



> Most importantly; is all this effort worth it


 :yes:

Unless you have a spring welling up in your basement this well help immensely!


----------



## Daniel Holzman (Mar 10, 2009)

The plan sounds reasonable. Few comments:

1. The depth of the pipe needs to be approximately 1 foot lower than the basement floor slab you are trying to protect against groundwater. The foundation is irrelevant, except insofar as it gets in your way. Most people try to place the pipe just outside the footer, and if you have a T footer the pipe often ends up directly on top of the wider part of the footer.

2. It is not necessary to have any pitch on the pipe, you can lay them flat. That is usually how I do my commercial jobs. The water will collect in the pipes and flow down to the sump, which of course is at a lower level, since it has a pump in it continuously drawing down the water level. The water in the pipes flow because of the difference in water elevation between the water in the pipe and the water in the sump, NOT because the pipe itself is pitched.

3. I usually use 4 inch diameter perforated PVC pipe, schedule 40, holes down. You can also use HDPE pipe. Stay away from cheap corrugated plastic pipe, it has a bad habit of crushing under load.

4. As to the drywells in your lawn, there is no way they are going to be big enough to store roof runoff, unless you put in a huge tank, and even then they are going to drain out into the soil (that's why you call them drywells). So the water that drains out is going to end up in your perimeter drain system, putting additional load on your pump and piping. Better to drain the roof onto the ground and have it run off to the street. This can often be done using extended downspouts.

5. Make sure the city is OK with you draining your sump onto the street. Usually they are, but you gotta ask.

Good luck with the digging.


----------



## coderguy (Jan 10, 2011)

Daniel Holzman said:


> The plan sounds reasonable. Few comments:
> 
> 1. The depth of the pipe needs to be approximately 1 foot lower than the basement floor slab you are trying to protect against groundwater. The foundation is irrelevant, except insofar as it gets in your way. Most people try to place the pipe just outside the footer, and if you have a T footer the pipe often ends up directly on top of the wider part of the footer.
> 
> ...


I find this very confusing?

This isn't a footing system, I am hoping to avoid excavating down to the footer of the house.

> Make sure the city is OK with you draining your sump onto the street. 
> Usually they are, but you gotta ask.

Milwaukee has the opposite problem with this; too many people draining their sumps and gutters into the sewer laterals. (http://basementconnection.mmsd.com/)

> Stay away from cheap corrugated plastic pipe, it has a bad habit of crushing under load.

I will avoid that stuff at all costs


----------



## Daniel Holzman (Mar 10, 2009)

My point about the depth was that you have to get the pipe lower than the surface you are trying to protect, which is presumably the basement slab, i.e. you don't want water in the basement, so the pipes need to be lower than the basement, which usually mean about a foot lower than the slab. Some footer are wider at the bottom than the wall, this is called a T footer, it is very common. For example, the wall may be 8 inches thick, the footer could be 2 feet wide. Your pipe can go on TOP of the footer, the key is that the pipe must be approximately 1 foot below the slab. If the footer gets in the way, you just move the pipe further away from the house.


----------



## coderguy (Jan 10, 2011)

Daniel Holzman said:


> My point about the depth was that you have to get the pipe lower than the surface you are trying to protect, which is presumably the basement slab, i.e. you don't want water in the basement, so the pipes need to be lower than the basement, which usually mean about a foot lower than the slab. Some footer are wider at the bottom than the wall, this is called a T footer, it is very common. For example, the wall may be 8 inches thick, the footer could be 2 feet wide. Your pipe can go on TOP of the footer, the key is that the pipe must be approximately 1 foot below the slab. If the footer gets in the way, you just move the pipe further away from the house.


So you are saying that this is a bad idea and that I should put a foundation drain in? If I were to do that; why would I do a dry well? I would tie the system into the sump pit? 

I mean; I get your point, and I have asked/talked about doing a foundation drain many times. There is no ability to get digging equipment into my yard; I would be digging my house out by hand. This was a differently proposed plan that I believe is based on my water problem being due to my neighbors yards all being at higher elevation and my back yard being graded towards my house (at 4%!)


----------



## Daniel Holzman (Mar 10, 2009)

I guess i totally misunderstood your post. I thought you were talking about installing a foundation drain (also known as a perimeter drain, sometimes called a French drain). Yes, a foundation drain would be an excellent idea, although I gather the digging part is trouble due to lack of access.

So let me start over. If you are not proposing a foundation drain, what is that "huge trench" you were talking about? Are you proposing to place drainage pipe on the surface or near the surface, directed to a drywell? I cannot see that accomplishing anything, since the surface water would flow into the drywell, leave the drywell via the holes in the drywell, enter the groundwater, and end up in your basement. Or maybe I totally misunderstand your plan.


----------



## coderguy (Jan 10, 2011)

Daniel Holzman said:


> I guess i totally misunderstood your post. I thought you were talking about installing a foundation drain (also known as a perimeter drain, sometimes called a French drain). Yes, a foundation drain would be an excellent idea, although I gather the digging part is trouble due to lack of access.
> 
> So let me start over. If you are not proposing a foundation drain, what is that "huge trench" you were talking about? Are you proposing to place drainage pipe on the surface or near the surface, directed to a drywell? I cannot see that accomplishing anything, since the surface water would flow into the drywell, leave the drywell via the holes in the drywell, enter the groundwater, and end up in your basement. Or maybe I totally misunderstand your plan.


The "huge trench" is what I used to describe digging down to place in the perforated pipe. I'm currently planning the top of the pipe to be 8 inches below grade... so probably 14-16 inch deep trench from back of house to front (according to picture).

With the drywell(s) 10 feet from the front of the house; won't that water be able to permeate into the soil/etc; instead of pooling around my foundation (all at the back of the house).

I also cannot stay connected to the city laterals forever; the guys in orange will make their way to my neighborhood and eventually tell me to disconnect. So if I do all the work of digging out the house (not completely against, but we're talking weeks of work here?); I'll tie that into the sump, and now I'll be putting even more water into the laterals. My sump currently pumps into the lateral on an exception from the inspector. But he warns in a storm the lateral could back up; flooding the basement, etc.

What do I do with the water?!?!


----------



## Daniel Holzman (Mar 10, 2009)

Normally it is illegal to connect your storm drain to city sewer, which is what it sounds like you are currently doing. But it is perfectly normal and common to pump out either to the street directly, if there is no storm drain system, or to connect directly to the storm drain system. In some communities, there is a storm drain system, but they do not allow you to pump directly into the storm drain, so you pump to the street. My town is full of sump pump connections to the street, you can always tell when they are running by the flow of water down the curb or gutter.

As for your plan, if you are getting water in the basement, and it sounds like you are, there is a high probability that the groundwater table is higher than the basement. If that is the case, then directing roof runoff into a drywell, from where it will percolate into the soil, is not going to help you at all, since the roof runoff ends up in the soil, and the water table is already too high. The whole point of a perimeter drain is to allow you to draw the water table down so it is lower than the basement, which will permanently solve you drainage problem. To help out, you of course want to direct surface water and roof runoff away from your house, in your case all the way to the street where it runs away to the storm drain system.


----------



## coderguy (Jan 10, 2011)

> Normally it is illegal to connect your storm drain to city sewer, which is what it sounds like you are currently doing.

That describes most of Milwaukee. My down spouts run into ridiculously old (iron?) pipes that poke out of my foundation, run into the basement and down into the basement floor (Then out to city sewer).

There is a huge movement right now to get everyone disconnected (been going on for years). I had already disconnected the front. Leaving me the two back down spouts and the sump.

I'm kind of sad here; your advice and joemama's seem to completely disagree.

Maybe I could just do the back of the house? (dig down to footing, put exterior drain, run into sump). Then run solid pipe to drywell with overflow to lawn (so overflow runs into the street?!?!).

I know for a fact I can't pump onto the sidewalk, or route under it... no real way to route water directly to the street.

Maybe I'll add some pics tonight...


----------



## pls8xx (May 2, 2009)

In most cases these problems are due to ineffective surface grading.

My quotes from some other threads:

_"Excess surface water should be disposed of with grading first, surface inlets and solid pipe second, and collected to a pump third."
_ _
"The proper use of french drains is to de-water saturated soil where the saturation can't be prevented by some other means."

"What you have described starts as a surface water problem. Subsurface drainage is a bad idea and anything constructed that allows surface water to permeate into the soil is sheer stupidity. French drains have become the biggest scam of the landscape industry."

"The first step in determining proper drainage for your property should be to assess the volume of water you have to deal with. This is a function of the size of the area. You should consider all rainfall from roofs and yards, including any area on neighboring properties that flows onto your lot._ _"

"It's best to do a plan view drawing of all your property. The drawing should show the location of any water coming onto yours and the size of the up-slope area as can best be determined. For legal considerations, the location of where water leaves your property is also important. In most states you may not block the natural water flow from a higher property, nor may you change the location or character of the flow as it leaves you property._ _"

"Adding ground elevations to your base map will then show the route that water takes and any places where the grading is not adequate or desirable for the predicted volume of flow. The elevation at the exit point is paramount to any drainage design, as all grading and any pipes used must be above this elevation."_ _

"A copy of lot survey or public records can be a big head start in creating the base map needed."
_
Should you go forward with this project as planned, you can be a big help to forum readers if you return a year or two from now and tell others what a big mistake it was. Maybe you can prevent someone else from installing one of those stupid french drains.


----------



## coderguy (Jan 10, 2011)

pls8xx said:


> In most cases these problems are due to ineffective surface grading.
> 
> My quotes from some other threads:
> 
> ...


Thank you for your um... suggestions.


----------



## pls8xx (May 2, 2009)

Sorry to have rained on your parade. Let me make up for it with a tip or two.

Keep all the water you can from reaching a level that makes it impossible to drain it by gravity to a discharge point. Fill and regrade for a uniform slope to the discharge point where you can. Sometimes a low foundation level precludes this method. 

Never let roof water get to a ground level below a suitable discharge point. For example, build a gate affair at a house corner. Catch the roof water high up on the house by turning the downspout into a horizontal pipe running across the top of the gate (7'high) to near the property line. Turn the pipe down but stop above ground level high enough to have fall to the street or other discharge point. Run horizontal above ground elevation in a pipe hidden in a hedge to the discharge. If you don't like the hedge, build a planter high enough to run the pipe through.


----------



## Daniel Holzman (Mar 10, 2009)

It is certainly a valid point to handle all surface water before resorting to a perimeter drain. However, it is not always possible to eliminate a groundwater problem, even with the most aggressive surface water management. In my neighborhood, for example, every house has a sump pump which typically runs a few days a year due to high groundwater, generally in the Spring, but occasionally due to hurricane floods in the fall. I don't know where in Milwaukee you live, but there are sections in most cities that are simply low lying and poorly drained, for which a perimeter drain is necessary to prevent flooding of the house.

I also note that it is common practice to build new houses with perimeter drains, even if they may not be strictly necessary, because it is relatively inexpensive to put them in during construction, and they work extremely well if properly designed and installed. Unfortunately retrofitting a house with a perimeter drain is much harder than installing during construction.


----------



## concretemasonry (Oct 10, 2006)

Some areas of older inner cities have a combined drainage system (sanitary and storm drainage) and try to encourage drainage to the surface and hope it will be absorbed. In this situation a sump with pop-ups is encouraged.


----------



## AllanJ (Nov 24, 2007)

Do not connect gutter downspouts to your perimeter drain system.

Almost all perimeter drain systems have a pit with a sump pump.

When retrofitting a building with a perimeter drain system, either inside or outside, do not 
dig below the bottom surface of the foundation footings (or foundation itself if no 
footings). or below a 1:3 slope going away. For example if the trench needs to be 4 inches 
below footing level it must be 12 inches away (not on centers).

You can connect downspouts to an underground drain pipe that leads away from the house that is
not connected to your perimeter drain. The former drain should be non-perforated for at least 20 feet 
away from the house.

Whatever you use, the water has to be gotten rid of. Drywells may or may not be sufficient and
must be some distance from the house. If water from the street runs down your driveway into you
property, then you should mold a rounded lip of concrete or asphalt at the front to prevent that.


> "What you have described starts as a surface water problem. Subsurface drainage
> is a bad idea and anything constructed that allows the landscape industry."


The first thing to do is to have no water pooling up against the house while at the same time
no water from downspouts, etc. is poured into holes near the house. It may be necessary
to regrade the land.

Subsurface pipes to a dry well are okay but need to be below the frost line in cold climates. 
The output of a sump pump (or a pipe from a pumpless pit at the end of your
perimeter drain system going directly outside) can go out underground but must
ultimately end up "in daylight" from favorable surface slope, or end at a dry well with
a pump to empty it out before the perimeter drain back at the house backs up.

The perimeter drain system must have air in it over its entire length. For this reason
the sump pump pit has to be large enough that the pump can come on before the
drain pipe ends as seen in the pit are significantly submerged, and the pump not
turn on and turn off in short cycles.



> "The first step in determining proper drainage for your property should be to assess
> the volume of water you have to deal with. This on neighboring properties that flows onto
> your lot."


 The most important thing is finding a place to put the water. Particularly if water comes
over from neighboring properties, it may be necessary for the water to be ended up
in the street.


----------



## CplDevilDog (Mar 18, 2009)

A foundation drain (below the elevation of the slab) is overkill (IMHO) unless you are dealing with a high water table caused by sub-surface water.

If water is seeping up near the center of your slab or through cracks in the slab vs coming through the walls then a foundation drain would be the way to go.

That being said I think properly constructed French Drains are money well spent.

Respectfully have to disagree with pls8xx. They wouldn't have made it from the 1800's if they were a scam. They just have to be done right.


----------



## coderguy (Jan 10, 2011)

CplDevilDog said:


> A foundation drain (below the elevation of the slab) is overkill (IMHO) unless you are dealing with a high water table caused by sub-surface water.
> 
> If water is seeping up near the center of your slab or through cracks in the slab vs coming through the walls then a foundation drain would be the way to go.
> 
> ...


In addition to having Joe out; I had another professional out yesterday. He recommended almost exactly the same... a drain for the future patio at the back, going into a french drain, as the drain goes around the house; switch it to solid and run second solid pipe next to it for the downspouts.

So the back of the house would be french drain; side of the house two solid pipes. The question is if I should do dry wall or just run the pipes right out of the front hill (with the pop-up valve thingy). I just imaging having sidewalks of ice in the midwest by doing that. Which is why I liked the drywell idea.

So confused now.


----------



## jomama45 (Nov 13, 2008)

concretemasonry said:


> Some areas of older inner cities have a combined drainage system (sanitary and storm drainage) and try to encourage drainage to the surface and hope it will be absorbed. In this situation a sump with pop-ups is encouraged.


BINGO! Not only do the old area's of Old Mil have combined sanitary & Storm, the whole Metro Milwaukee Sewage District empties into combined. The whole system isn't very old either, but was never designed for the actual amount of water it see's, which is why it's dubbed by many as "The not quite deep enough deep tunnel......" Being as such, there's no way coderguy will be able to tie into the storm sewer, because there really is no such thing, and as he mentioned, their already scratching their heads on how to get as much groundwater out of the system as possible already.

As for the actual site, there's no way IMPO to run water completely on the surface successfully: His garage,and alley, are a few feet higher than his foundation. The property lines are extremely close to his and nieghboring homes as these are likely only 40'-45' wide lots. One of the neighbering homes is higher, the other already has soil over the siding. 

Coderguy, I don't really care for drywells myself, and have seen where many of them have been unsuccessful, but with your hill at the front, I think it would slowly leach out just fine most of the time. As for just having the pipes exit above grade/through the hill that will work undoubtedly, but is generally frowned upon due to the potentially dangerous conditions it creates on the sidewalk, especially ice.


----------



## concretemasonry (Oct 10, 2006)

Jomama -

I know the MKE area reasonably well and so much of it is so flat and not far above Lake Michigan. I can understand the combined collection systems because the federal laws about dumping into the lake require some sort of treatment by and sometimes a single plant is cheaper to build and operate than tearing up the city streets and sidewalks to create two separate collection systems, especially when the downspouts are involved. At least all of Lake Michigan is in the U.S. and not an international lake like some of the other Great Lakes.

Dick


----------



## jomama45 (Nov 13, 2008)

Dick, the problem is the system gets over run with sewage quite a few times a year and they end up dumping tens of millions of gallons of untreated into the lake every year. They're trying to figure out a decent plan now, and so far it looks like the simplest is for them to pay to have sump pumps placed in accepting HO's basements that discharge to grade and abort the current Palmer valve in the basement floor drain.


----------



## concretemasonry (Oct 10, 2006)

That is exactly what they allowed in MSP while they split the combined collection system (over 20 years) into separate systems (sanitary and storm from surface rainfall).

There, the storm water would knock out the top drainage boards and the excess sewerage went into the Mississipi river, but only in high flow periods, so the dilution solution concept minimized the effects. The systems finally got 80-90% separated. Actually, the Mississippi river is cleaner than the Minnesota river when it enter the MSP area because of the fertilizer and silt in the Minnesota river, but a sewerage plant can't do much about that.

Dick


----------



## coderguy (Jan 10, 2011)

jomama45 said:


> Dick, the problem is the system gets over run with sewage quite a few times a year and they end up dumping tens of millions of gallons of untreated into the lake every year. They're trying to figure out a decent plan now, and so far it looks like the simplest is for them to pay to have sump pumps placed in accepting HO's basements that discharge to grade and abort the current Palmer valve in the basement floor drain.



I feel like I have to defend Milwaukee a bit here 

The last 15 years; there has been tremendous effort to improve many parts of the city, especially this water problem. There is a separate system now; and there are active programs to go through neighborhoods and find where water is getting into the wrong one and correct it. 

There is also a program to go through some of the worst offending neighborhoods and get people disconnected from the laterals.

Here is an example of the awareness program (it was supposed to be a funded incentive program, but we couldn't afford it): http://basementconnection.mmsd.com/

You can see another example by visiting the lake front; where we now have rain gardens every mile or so; with signs explaining their purpose. They have a feed grate in the center for water to come up; keeping more water out of the lake. My explanation here is bad.. I'm a programmer not a landscaper 

I think this relates to my post in that I am voluntarily attempting to disconnect from the laterals over time (starting with the front, now the west side of the house). But being in the midwest; as discussed, dumping water on the sidewalk will result in a dangerous ice situation. Dry basement + disconnect from laterals; but with a nice benefit of getting those nasty pipes out of my basement (then remove them and add a one way valve going out to the street!)

The drywell still seems like the solution, I'd love to dig less holes; so if someone has a different idea....


----------



## concretemasonry (Oct 10, 2006)

coderguy -

A drywell will work well if it is large enough and AND the surrounding soil will accept the water and distribute it.

Dick


----------



## House Engineer (Feb 23, 2012)

I always build as much slope into a drain tile as I can. It helps to increase the amount of scouring by the draining water, to reduce the amount of accumulated sediment in the pipe.

I built a French drain with a pop-up drain that works well. It is built on sandy soil, so the catch basin drains 24-48 hours after the rain stops, through holes I drilled in the bottom of the catch basin. When the water exceeds the capacity of the catch basin, the water discharges onto my lawn through the pop-up drain. The top of the catch basin is removable, for cleaning when it is needed. You can see photos of my French drain at this link: http://housengineer.com/825/


----------



## coderguy (Jan 10, 2011)

House Engineer said:


> I always build as much slope into a drain tile as I can. It helps to increase the amount of scouring by the draining water, to reduce the amount of accumulated sediment in the pipe.
> 
> I built a French drain with a pop-up drain that works well. It is built on sandy soil, so the catch basin drains 24-48 hours after the rain stops, through holes I drilled in the bottom of the catch basin. When the water exceeds the capacity of the catch basin, the water discharges onto my lawn through the pop-up drain. The top of the catch basin is removable, for cleaning when it is needed. You can see photos of my French drain at this link: http://housengineer.com/825/


Yes, you've posted that before in other threads. Some good pictures.


----------



## House Engineer (Feb 23, 2012)

Sorry about that double-post Coderguy. No wonder it seemed to sound so familiar


----------



## pls8xx (May 2, 2009)

All I have is an opinion; one that is not embraced by either homeowners or contractors. But before you dismiss my contention that few french drains are anything but a bad deal, you might consider my background.

I started following a survey crew around when I was 10 years old as they did work on civil engineering projects. By the time I finished high school I could operate all standard survey instruments and perform most common field engineering calculations. I went on to have a 50 year career with consulting engineers, contractors, and land development firms.

*Rule #1*, drummed into my head by my father before I turned 15, for every project built on, or a part of, terra firma: 
*The first thing to consider in design, and the first thing to do in construction, is to take positive control of the water. 
*


I have no motive for what I say here; no book for sale or other means to make a profit. But the people who sell the materials for subsurface drainage and the ones that install them do; they make their living giving homeowners what they ask for, and frankly a lot of homeowners are practically begging them to take the money.


Now I speak not against a properly constructed perimeter drain at footer level *where all the other aspects of surface drainage have been attended to.* Such perimeter drains are good insurance and seldom are required to pump much water. And yes, the very small amount of water from a basement sump can be discharged to a dry well some distance from the home if the amount is no more than 5 to 10 gal. per day. Dry wells for yard water where the surface drainage is bad are a joke.


Proper surface water management prevents the soil from becoming wet from the start. On flat ground, if the soil is allowed to absorb water until it is saturated, there is seldom a good fix to the problem. Every site is different and it is usually necessary to do an in-depth study to determine how to best handle surface drainage. French drains are promoted as a one-size-fits-all solution. If the surface flow is corrected, most french drains are not needed, and if the surface drainage is ignored, they seldom get the desired result.


One might ask why french drains sometimes appear to have solved the problem. Several years ago I talked to a friend that is a landscape contractor that does mostly commercial but also some residential work. I expressed my distaste for the inappropriate use of shallow french drains. His reply went something like this:


"Well yes, but what you fail to consider is that homeowners want a french drain. So I do them .... sometimes. What I do is look at the site. If I can spot an easy way to fix the surface drainage, I tell the homeowner that the french drain should be located in the area I need to work on to correct the surface drainage and that the heavy equipment used will tear up a wide path. Not to worry, I'm going to fix it all back better than before. After fixing the surface drainage, I compact the drain trench so that little if any water ever gets to it. If I can't do it that way I walk and let some other noob have the job. I never get a call back for a french drain not working because it doesn't need to work."


"Am I selling something not needed? Maybe, but if I don't do the french drain, the homeowner just gives the job to someone that will. In the end I fix the homeowner's problem and they don't complain. If my competitors do a french drain to fix a surface problem and it doesn't work they get a lot of bad will. I don't need that." 



No one likes to think they wasted their money. Homeowners that spend a lot to have a french drain built may recognize that the problem was not totally fixed but they like to think the situation is better than it was. 



So, how bad *can* it get? I found this blog ...


Wet Basement


----------



## coderguy (Jan 10, 2011)

pls8xx said:


> All I have is an opinion; one that is not embraced by either homeowners or contractors. But before you dismiss my contention that few french drains are anything but a bad deal, you might consider my background.
> 
> I started following a survey crew around when I was 10 years old as they did work on civil engineering projects. By the time I finished high school I could operate all standard survey instruments and perform most common field engineering calculations. I went on to have a 50 year career with consulting engineers, contractors, and land development firms.
> 
> ...


I have to be honest, I feel you haven't even been reading the thread; just blindly responding.


----------



## coderguy (Jan 10, 2011)

So I did the test dry well this weekend;

Took a post hole digger and went 4 feet down. Poured in a 5 gallon bucket of water. It drained quickly at first; then drained at just under 3 minutes per inch. When it got low (and I had to leave); I poured another 5 gallons of water in. When I returned home the hole was empty.

I checked it again this morning, and the hole isn't "dry", but there is no standing water / etc.

Should I test more? Is the drainage good enough? (when coupled with overflow spout)


----------



## pipeninja (Mar 19, 2012)

Hey man, I haven't read every post on here, but I HIGHLY recommend not using dry wells. Is there any way to just daylight the water away somewhere? Even if you can't get 2% pitch of fall on the pipe.. it's better to do that then use dry wells. My company never uses dry wells, they just don't work well. ***embedded links not allowed*** :thumbsup:


----------



## coderguy (Jan 10, 2011)

So the guys did the work on the basement yesterday/today. They apparently thought I was doing this soon, as they left the foundation mostly dug out.

So I need to make a decision quick; buy equipment and get to work.

If you think the french drain or the dry well is a poor idea; please speak up soon and say WHY (after reading the thread). Please also suggest an alternative in my situation.

If you think it may work, please post any tips or encouragement. 

I had a horrible time with the contractors today; as they raised their price before they left.


----------



## pipeninja (Mar 19, 2012)

If a drywell is the only feasible option for you, then do it. I am just saying that if possible, it would be better to simply daylight the water out ontop of the ground somewhere rather than into the ground. There are times when a lot is too flat to have any kindof drain, and I suppose a drywell would have to work. Like someone mentioned on this thread before, just don't tie the gutters into the perimiter drain. I don't think it would handle it, and then your gutters would back up, and then you would have another problem to deal with. And here's another statistic to think about(sorry to throw all this at you). I read in a drainage magazine that 1 inch of rainfall on a 2,000 sq ft residential roof generates 1,100 gallons of water. How big are your drywells going to be if they need to collect 1100 gallons just from your roof? If they can't take the water, your gutters will just start blowing out against your foundation. I hope this helps you make your decision, let me know how it all turns out. Good luck friend!

Rochester Excavating :thumbsup:


----------



## coderguy (Jan 10, 2011)

pipeninja said:


> Like someone mentioned on this thread before, just don't tie the gutters into the perimiter drain. I don't think it would handle it, and then your gutters would back up, and then you would have another problem to deal with.
> 
> :thumbsup:


So where would you suggest to drain the gutters to? My sidewalk? The thread discusses using an overflow drain; which is exactly what I plan.

If I don't disconnect from the laterals, eventually the city will come through and force it and I'll be back to where I am now. I can drain to the alley or the front yard. I added gutters to the garage and they both run to the alley.

I have 4 downspouts and a sump pump. I'm draining two onto the front yard (long extensions), and 2 into the laterals. The sump currently goes into the lateral; by a temporary except from the inspector.

I do not understand how the dry well hurts the process, and I do not understand what I am supposed to do with the water from the gutters.


----------



## pipeninja (Mar 19, 2012)

I'm not saying you cant use the drywells, just overbuild them if you end up using them. Just to be sure, there are no storm drains anywhere you could tie into, right?


----------



## coderguy (Jan 10, 2011)

pipeninja said:


> I'm not saying you cant use the drywells, just overbuild them if you end up using them. Just to be sure, there are no storm drains anywhere you could tie into, right?


I don't believe I am allowed to request or attempt to tie into the storm drain system. We're supposed to get our water to the street.


----------



## coderguy (Jan 10, 2011)

*final plan?*

Here is the plan. Looks to cost about $300 before dry well and pea gravel.

I think the grade is good, level in the back.

This should hold the house over nicely until we can regrade the back (retaining wall) and the west side.


----------



## pls8xx (May 2, 2009)

In response to my post, coderguy said:

_"I have to be honest, I feel you haven't even been reading the thread; just blindly responding."

_Did I miss something in the discussion? I believe I did. When Daniel Holzman imdicated that it's only a proper foundation perimeter drain that would protect your basement, I missed where you pointed to a recognized drainage authority stating that a shallow french drain can accomplish the same result. 

When CplDevilDog posted about the need to calculate the proper size for the dry wells, along with a link to do that, and concretemasonry confirms the need for a sufficient size for the dry wells, I missed where you added up the square footage of the roof and yard areas and made use of the resource to determine what the size should be.

And your contention that I am "blindly responding" is also correct. Since there are none of the details and accurate elevations given for the site, I have no way to assess what might be a solution for your situation.

Your use of grid paper to do a plan view drawing may look a bit crude, but it is a step in the right direction. You should augment the plan view drawing with a profile drawing along the drain route showing the ground elevation and the pipe/trench details. This would help you to see how the system will or wont work during a rain event.

Such a profile drawing might look something like this:


----------



## coderguy (Jan 10, 2011)

pls8xx said:


> In response to my post, coderguy said:
> 
> _"I have to be honest, I feel you haven't even been reading the thread; just blindly responding."
> 
> ...


First, your drawing is pretty accurate to my plan. I hadn't thought of doing a profile drawing like that; I will have to work on it tonight.

Regarding the math; you are correct. I broke my own rule that I spout on the financial forums... which I realized last night after I did my drawing and didn't have a size for the dry well.

Last night I argued your points with my wife; because the whole thing started to make less and less sense to me. I eventually came out convinced of the physics of a french drain, and moved on to the dry well.

I did the math for our yard; and even tried doing it for just the back/west rear of the house (What would feed into the dry well). It appears to require about 4ftx4ftx5ft (2 drywells near each other, at 3ftx3ftx5 seems like a better choice, and take over an inch of rain). That is for a filled system though. I'm thinking one 3x3x5 system since I would do for a flo-well or drum (some type of lined system).

I will reply tonight with a profile drawing of the property.

Finally; I make no claim this would work as well as a foundation perimeter drain.


----------



## AllanJ (Nov 24, 2007)

Don't forget that water that soaks into the soil not far from the house may find its way back to the basement and have to be re-pumped away. But if the soil out where you have a dry well is very porous for many feet down then the dry well will provide enough drainage.

To put things into perspective, a French drain must empty out and take the water someplace. A "French drain" in which water is supposed to remain until it soaks into the ground around the perforated pipe is properly called a leach field even when constructed in the same fashion as a French drain. When a French drain empties into a dry well, the dry well is considered full when the water level mostly covers the end of the drain pipe as seen.

In winter there should not be frequent instances where large amounts of (liquid; unfrozen) water get collected and also there is a prolonged time where it would freeze on the sidewalk or pavement. Therefore most of the time discharging the overflowing dry well (a sump pump inside it should empty it out completely before shutting off) across the sidewalk to the street works okay and should the rain storm be followed by a freezing snap, ice melting salt can be put on the sidewalk manually.


----------



## coderguy (Jan 10, 2011)

So I got out in the yard for a bit before it got dark and remeasured some slopes. I then made this side view of the plan that is attached here. I hurried and they aren't perfect; but it shows just how bad the back yard is (slope wise).

I think it may be that I'm exhausted mentally and physically; because I have no idea what to say.


----------



## pls8xx (May 2, 2009)

Your new drawing appears to be a cross section of your property from the far back to the front showing only a part of the pipe network. The profile of the pipe should be along the route of the pipe as if the layout were unfolded to a straight line. The ground line should be the elevation above where the pipe will be laid. Perhaps this will be clearer if I show the correlation with the two together. 










Since my profile appears to be somewhat like your situation, I will use it to assess how the system will function under varying rain events.

Condition 1. Suppose there is a small rain event. One where there is enough rain to have a small flow across the ground to your drain trench. In my area small events are more common than large events. Water enters the trench and fills up the gravel below the pipe but not high enough for it to enter the pipe. Some of the water will flow through the gravel into areas downstream from the perforated pipe. The drawing below shows the saturated gravel shaded in red.










Since none of this water will ever flow down the pipe, all of it will be absorbed by the lower soil adding to any saturated condition of the soil next to your basement wall. Which is the very thing you are trying to prevent.

Condition 2. Suppose you have a very large rain event; one greater than what the dry well is designed to handle. The dry well will quickly fill up and go into overflow mode. The elevation of the overflow will determine the water level in the far end of the pipe; water in the trench at the back of the house has to be higher than the overflow elevation to make any water flow. As shown in the graphic below everything below the red line will be full of water. 










While this condition exists water from the trench will be dissipating into the soil just as if it where a dry well. Moreover, after the rain stops and water no longer flows out the overflow, the water in the dry well and the water in the trench will go down together. Each being absorbed by the adjoining soil. I'm thinking hundreds of gallons of water dumped to the soil along your basement wall.

Condition 3. Things are better here. This is for a rain event that matches what the system is designed to handle. Condition 1 will exist throughout the event, but the bulk of the water will run to a dry well sized to take the water without a back up. Well, that is if the well is empty when the rain event starts, which might not be the case. You know that at some depth your soil is prone to be saturated. That's why you have a wet basement. If the bottom of the dry well is below the saturated level then it will fill up to that point. A well half full of water wont handle the designed event resulting in Condition 2. Since you live in a cold climate, a large part of the well may be full of ice.

French drains can sometimes serve to dry up the soil above the pipe elevation. But the soil below the pipe often becomes wetter than with no drain at all. For this reason, a shallow french drain near a basement which is lower than the pipe is a bad idea.

So what could be done for this property? I'll talk about that in my next post.


----------



## AllanJ (Nov 24, 2007)

Note also that the drain pipe 1-1/2 feet below the surface can freeze up.

You will probably need a foundation perimeter drain below basement floor level also. Right now there is not way to prove that you definitely need that because you have not finished correcting the problem of gutter water pooling up against your house.

What would happen if you drained/pumped all the water to the alley with no dry wells?



> had a horrible time with the contractors today; as they raised their price before they left.


What has been excavated so far and how far?

I looked at your diagram again and I think the dry wells are too close to your house. At least to ensure that you will need a perimeter drain system which is actually a separate project.


> my neighbor put his new sidewalk ON TOP OF his old one; and yes it is angled away from his house...


It would be a good idea to regrade your land away from your house on that side. If desired, dig a trench along your property line on your side which will act as a degenerate form of the French drain; on the surface. Fill it with gravel, no pipe needed except at the low end to connect to an underground pipe. If combined with a flower garden (unwalkable space) then it can be filled with clay-ey topsoil instead of gravel and with a continuous row or column of bricks or blocks mortared together and extending above grade for a few inches and below grade for several inches to block water flow from your neighbor's sidewalk.


----------



## coderguy (Jan 10, 2011)

> What would happen if you drained/pumped all the water to the alley with no dry wells?


I have no idea how this would work.. my backyard rises almost 17 inches from house to garage; meaning the same or more for my alley. It would be awesome is what would happen; but I don't think a sump pump is going to move water like that. Where/how would I do the piping. Most importantly, water isn't making its way to the sump pump... it's sitting in the blocks and against the back of the foundation. Making its way through cracks and running down the bilco stairs.



> It would be a good idea to regrade your land away from your house on that side.


I have about two feet on my neighbors side and he is above me, and has added an additional 2-3 inches with his new sidewalk. I would have to bury my house to grade away from it. Even if I do regrade now that the windows and window well are gone... 2 feet will do it?

I cannot simply regrade the back yard; the grade would end below my garage. I am willing to put a retaining wall there to do this. In that case; water would run towards the retaining wall; nobody has commented on this.


----------



## AllanJ (Nov 24, 2007)

The purpose of a perimeter drain system is to get the water over to the sump pump instead of seep up onto the basement floor surface.


----------



## coderguy (Jan 10, 2011)

pls8xx said:


> So what could be done for this property? I'll talk about that in my next post.


I look forward to this post.

My major reasoning in posting the second drawing was to communicate how bad the slope is in the back (back yard rises about 17 inches from where it is at the house).

I'm strongly considering a retaining wall in the front yard (instead of the ugly hill); with matching one in front of the garage (with front yard, back yard, and side yard regraded professionally afterwards - before?). This would include digging out the back of the house; repairing mortar as needed; adding exterior drain tile and tying it into the sump.

I have also been in contact with basement systems; and they have agreed to come back and work with me on why I paid them so much to still have a wet basement. We seem to be in agreement that their install had some type of error (interior drain tile). Unfortunately they won't come until the 4th (hmm...).

I still have the plans for this french drain, and it still sounds like the best idea; not sure about the dry well though. Thinking just run everything out of the hill. Not happy about it though; as I don't want to wash away the grass or have an iced sidewalk in the winter.

For now, the french drain AND dry well plan stands; while I estimate the retaining wall costs (seems to be 1100.00 for the stone; so my rough estimate is $2,800.00 for the front and back. Versa-lok from "The Brick Yard" as suggested by Joe). Full update about this in the gallery thread this weekend.

My current estimate for the drywell / french drain is about $500.00

Even if I don't do the french drain / dry well; then I'd be looking for suggestions on the west side downspout. If I do the retaining wall and regrade the back yard; do I just run the down spout away from the house in the back yard? 

So many questions. I will spend most of the weekend on this again.

Again, looking forward to responses and loving that this thread has so much information in it.


----------



## pls8xx (May 2, 2009)

Regrade the backyard. Build a terrace near the garage with a 4:1 or 5:1 slope so that the toe is only slightly above the ground grade at the house. Between the garage and the house put in a two slight depressions of around 4 inches deep. In profile it should look something like this:










The plan view will look something like the graphic below. Since mere inches in grade are important, I show the contours in 0.2 ft intervals. Blue arrows show water direction.










Install surface inlets in the depressions with solid pipe laid shallow at the inlets. The higher starting pipe grade will give a better slope (1% min.) to the house corner. Continue the pipe to daylight in the front yard. If you do the dry well, do it as a side diversion that can be blocked off if needed. The main pipes should all be sloped so that no water is retained in them after the rain stops. I would make a serious attempt to carry the water all the way to the street. But without an accurate profile of the ground, sidewalk, and curb, I can't say what the design might be.


----------



## coderguy (Jan 10, 2011)

pls8xx said:


> Regrade the backyard. Build a terrace near the garage with a 4:1 or 5:1 slope so that the toe is only slightly above the ground grade at the house. Between the garage and the house put in a two slight depressions of around 4 inches deep. In profile it should look something like this:
> 
> 
> 
> ...


Well, that is definitely an approach. Could I not do the retaining wall; your approach seems like it makes the back yard quite unusable (no patio, etc).

Curious what others will say about your proposal.

I do appreciate all the time you obviously put in. :thumbup:


----------



## pls8xx (May 2, 2009)

The retaining wall has to come before the patio. Do the wall, cut the drain pipe and reroute to surface drains at the wall, then do the patio. The regrading I've shown is compatible with this future work.


----------



## jomama45 (Nov 13, 2008)

pls8xx said:


> Regrade the backyard. Build a terrace near the garage with a 4:1 or 5:1 slope so that the toe is only slightly above the ground grade at the house. Between the garage and the house put in a two slight depressions of around 4 inches deep. In profile it should look something like this:
> 
> 
> 
> ...


You're plan isn't really any different than what he originally suggested he was going to do, other than you cut out about ten feet of french drain & replaced it with an additional surface drain.

The problem with the *bold* part is that his drainage pipe would have to cross over the top of the sidewalk to do so, which obviously isn't going to fly.

George, just to make sure you understand what I originally suggested, don't try to simply rely on one dinky post hole to be a reliable drywell. You''re going to need to install at least 1 yard of stone in the front yard for this to work well IMO.

As for the retaining wall in front, this would leach the water even faster, but the block will remain wet for days (maybe weeks?) which may not be desirable asthetically, and may also have negative consequences on their integrity. Not sure what to think of it as whole yet (it's early) but maybe Dick (concmasnry) will comment, as this is the kind of knowledge he certainly possesses.


----------



## coderguy (Jan 10, 2011)

jomama45 said:


> George, just to make sure you understand what I originally suggested, don't try to simply rely on one dinky post hole to be a reliable drywell. You''re going to need to install at least 1 yard of stone in the front yard for this to work well IMO.


Yep; the post hole was just the test we talked about. Planned to do at least 1 flo-well to start, possibly adding another. I had planned to do a second test hole more towards the center of the yard (but still 12+ feet away from foundation)

Even looked at some of the stuff online where people made dry-wells out of 55 gallon drums.


----------



## AllanJ (Nov 24, 2007)

The purpose of filling a dry well with crushed stone is to keep the soil above from collapsing into the dry well under the weight of persons walking above. The crushed stone drastically reduces the capacity of the dry well.

You might consider putting the dry wells in the back yard only, with sump pumps to empty them out to the alley when they are not frozen.

What does the front yard look like and what is the existing grading and contouring?


----------



## flyinferg (Mar 25, 2012)

*french drain sock*

hi, i am finishing my own french drain and i skimmed your material list. are you going to put the pvc into a "sock" ? i laid landscape fabric in hole, put in gravel, pulled the cool pre-made "sock" onto the pvc pipe, put that in the hole and then added more gravel. the sock keeps all the small stuff out of the holes, really inexpensive. please excuse me if i overlooked that item on your material list. i did the whole process myself and you will be sooo happy when you are done !! good luck, madeleine


----------



## AllanJ (Nov 24, 2007)

"Socks" may impair the performance of smooth pipe used in French drains. The fabric may cling to the pipe and only the half inch or so diameter patches directly over the perforations in the pipe may pass the water for awhile and then get clogged with the small stuff. Whereas with the landscape fabric and some gravel between that and the pipe, most of the surface area of the fabric is available for water to pass through.


----------



## coderguy (Jan 10, 2011)

So..

Alternative plan (actually, all plans combined?!?!)

1) Build a retaining wall in front of the garage (so that the top of the wall is 1 foot away; meaning the base stone must be 15 3/4" away. Assume versalok 16"x12"x6"). Wall will include stairs up to garden area (already stairs there, so replacement).

2) Grade backyard 1 degree towards garage.

3) Continue current retaining wall out towards alley; as side of garage is also steeply graded towards our garage. Back fill neighbors side; make him even happier than he was when we removed the trees/fence. Level our side. We finally have a garden.

4) Repair rear window; add glass block + window well.

That makes the first two pictures.... Then we have the next step; drainage. So see the third picture. Black is french drain (normal type behind a retaining wall...) and the light blue is solid pipe. The question is;
what to do in front of the retaining wall? Surface Drains? Can you put a french drain in front of a retaining wall?!? (lol at logistics). Or is that part simply not needed? (gutters all going up front, garage gutters go to back; so its only the yard water). 

pic 1) as the yard is now.
pic 2) Just add walls, etc.
pic 3) drainage plan.

Edit: since we want to put in a patio later, would we just run the solid pipe right across just in front of the retaining wall and put some surface drains in the patio? Unless of course the drainage isn't an
issue anymore...


----------



## pls8xx (May 2, 2009)

Now that's starting to look like a reasonable plan. Install drainage behind all new walls to meet the block maker's specs. If the existing wall along the side has less than 2ft of grade difference from high side to low, I would skip putting in a french drain there. 

With the new grade pushing all the water toward the garage wall, surface drains will be needed along the front of the wall. If the patio will extend all the way to the wall, I would consider using a narrow channel drain rather than a series of surface inlets. 

Stopping excess water from ever getting into your soil will dry things up. But the high water table around your basement will take some time to go down. Don't expect it to happen overnight.

A few days ago I would have bet money you would build that french drain around your house. Considering the hype french drains get it's no wonder homeowners so often do it.

Contractors build them either because they don't know any better or the homeowner is standing there with money in hand and they just don't care. Most all of them get away with it. But almost every time I see this issue in litigation where the contractor has to pay up, he built a french drain along a basement with the pipe well above footer level.

These two cases are typical:

Cofield v. Ghores Construction

Wallace v. Aspen Builders


----------

