Exterior Drainage

My back yard is quite large with a slight but steady pitch towards the home. In Spring I had planned to add a french drain which would drain to the street. A contractor has since told me that because the soil is almost solid clay under 4’’ of dirt, I should regrade the property and let the water drain away naturally. I’m trying to keep as much water away from my crawl perimeter drainage tile as possible.

With a large yard, it sounds like directing to a swale and away may work well.

I agree with the contractor. It’s always best to prevent the water from getting to the structure to begin with. Depending on your property and it’s layout, a swale may be an option to consider.

Hmm. Well if it is only 4 inches of soil and then clay, that could save you some work. The water won’t penetrate the clay so it would sit in the soil on top. I would go with the linear french drain but only about 6 inches into the clay, install the corrugated pipe with sock and gravel, landscape fabric and then cover with dirt and whatever you had growing there.

The clay should act as a barrier and direct the water into the pipe and away from the home.

I wouldnt want to do a full grading. Too much work and you then have the clay at the surface unless you strip the topsoil, grade heavier and re-install the top soil. Otherwise nothing will grow there.

I wouldnt expect a contractor possibly looking for work to come up with anything but a larger project. My 2 cents. Good luck.

Erol, is this Deja Vu, I thought you had that fixed?:slight_smile:

When some people speak of a “French drain,” they refer to a trench in which a drain pipe is laid, but the traditional French drain is basically a trench filled with gravel.

I am not against what Steve mentioned, but considering that the slope is towards your foundation, the contractor might not have been off base.

Considering that the lot slopes towards your foundation, you either have to build the grade up so to maintain that 6" in 10’ or create a swale 10’ away or more if possible.
The French Drain works great when the ground is not frozen.
If the slope is towards your foundation, during the Winter and early Spring, the water will still find its way to the foundation. Since the ground is never frozen near a foundation due to thermal breach of the condition spaces, water has a clear chanel to go down to perimeter drainage, and if none is installed, it could be a problem with hydrostatic pressures or leakage through the wall that is already comprimised with cracks.

The sure fix is stripping the loam and swaling the property properly so you can sleep at night. :mrgreen:

Hi Marcel,

In September, I did have new drainage tile installed in the crawl along with concrete encapsulation. My goal is now to try and keep water away and not look at my sump pump as a solution. :cool:

Hi Erol. I hope all is well.

Marcel was right on with the freeze consideration.

Regrading and a swale sounds best for your situation.

sorry but water will PENETRATE clay,sure it will.Have seen it right up close,digging the shtt out around homes for 3 decades.Itll penetrate clay around a house whether someone installs some type of swale or not,have seen many install all different types/depths of swales/drain tile.Some attemtped pouring concrete (a few builders own houses) along/against their basement wall/crawl-wall,they dug out 1-3' deep and 1-2'wide,poured concrete and then raised the grade atop the concrete,still leaked and THEN 'fixing' their actual problems just got MORE expensive. (exterior cracks). Water may not penetrate clay as quickly as sand etc but it will penetrate.(expandn contract)

John is correct, a swale will divert most of the run off, the clay will still obsorb the water at a slow rate.
I think the key here is to divert as much water run off away from the foundation as possible and then deal with the other problems such as water proofing and infiltration near or at the foundation.
My own property is all clay also. Knock on wood, I have a complete dry basement for the past 20 years. No sump pump. I can hear the water trickling down the drain from the floor drain. I am on of the lucky ones for a late 1960’s build. :slight_smile:

Mr Errol,

We wish we could help you better,no shtt.
I do not know what your problem(s?) are,sure…TRYING to divert ‘some’ water away may indeed help, im NOT saying do not try or it wont help at all.

What i`ll say again is, MOST crawl-walls have NOTHING on the outside to stop water from entering/penetrating the blocks and joints.THIS ‘could be’
part of your problem. It has been part or all of many others problems.
Have seen MANY homeowners DIY or hire contractors to play-with-the grade, only to continue to leak.Spent money…time…hoped and prayed and still leaked.
Yeah sure,a few DID ‘slow down’ the amount of water that entered.Thats NOT fixing the dang problem(s).

My impression of Erol’s question is that he does not have a leak entering his crawlspace. He is attempting to reduce the demand on his sump, resulting in his sump being secondary as opposed to primary control to runoff.


Check that spelling,sorry…Erol,

Mr Jeff,
cant remember all but he has posted/asked some quests etc before, was just trying to point out a couple of facts and my experiences was all.

Yes, I understand, and was hoping you would chime in, as I appreciate your posts and knowledge/experience. Erol is one of a few here that I believe would not cut corners with something like this. Thanks for your input to help Erol.


Yes that is exactly what I’m trying to accomplish. :wink: Crawl space is bone dry with a high quality Zoeller pump for the drainage tile. There isn’t a single crack on the visible portion of my foundation inside and out. Simply looking for ways to give the Zoeller a break now and then.

Erol, is there a possibility to connect the perimeter drainage system to a positive outfall?
It appears all the exterior ground water is being introduced to your pump at the interior. :slight_smile:

This is why I originally thought of adding french drains at the rear of the home that would collect some of the water before it reached crawl space drainage tile. You had indicated french drains may be OK except they would freeze in the winter. But then again, drainage is not an issue in freezing weather. With that said, wouldn’t a french drainage system in the yard be more effective (and less expensive) than a regrade with swales?

By the power vested in me by the State of Confusion, I hereby knight thee, Sir Erol. As part of the knighthood, you are hereby granted the right to install thee a moat around thine palace. Filleth it with water and Northern Gators that can take the cold and not only have you turned lemons into lemonade, you can get rid of your security sytem…

As stated, a swale is the best upgrade for any hillside home. If a swale is too costly, then at least consider having some sort of french drain installed out and away from your property to convey the draining water out and away from your property before this drainage even gets a chance to accumulate close to your home.

This is one hillside home (nightmare) that I inspected in 2008…

If a French Drain system is to work, it cannot freeze over to take care of ground water during early Spring and Winter thaws.


In order to be functional, they have to be able to drain to a positive outfall on the property or directed to a single or multiple drywells.

Hope this helps a little. :slight_smile:

It can be a problem in freezing weather.

See David’s pictures of standing water around foundation. The ground is still frozen but there is melting conditions with the problematic water running to the house foundation.

It is best to keep the drainage away from the potential of heading to the foundation, IMO.