# Looking for some help on unique negative grade/flooding issue



## JSDNJ (Jan 2, 2017)

I posted an old thread on the general forum a while back but cannot seem to find it. This is an issue I am still dealing with.

My house is simply too low into the ground. It was built in the 1920s. The yard itself is level, but close to the house I have a negative grade to avoid having to put soil up against the siding. So the water basically pools around the perimeter of the house in heavy rains.

I cannot regrade without making a big pit in the yard, and my neighbors behind me are above me on a hill, so there's just no practical way to fix the grading the traditional way.

I DO get water in the basement but it usually comes from the ground/perimeter and is relatively minor. However, once in a while when we have massive downpour, water will actually pour OVER the sill as a result of this condition. This is very rare and only in extreme circumstances. Pics below of what I mean:



















I have had several professionals come by and offer opinions ranging from 'Yea that's bad' to 'I'd sell the house'

Selling the house is not an option. I have a couple thoughts:

1-Dig out the soil a couple feet away from the foundation, place cloth, perforated pipe, clean stone along the foundation to carry the water away to daylight in the front. This will not correct the grade, but will hopefully carry the water away instead of pouring over the sill.

2-Build a retaining wall ~3 feet away from the back of the house, and created a proper grade between the house and the new retaining wall, with perforated pipe buried at the base of the wall. This is the more invasive and expensive option.

I am open to any other ideas. I appreciate any input.


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## Mystriss (Dec 26, 2018)

The first one's a "french drain" and I'd say that's the option. A retaining wall will seep water through, they sag and lean, etc. IMO it's not worth the hassle and it'll look odd.


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## Nealtw (Jun 22, 2017)

I would dig trenches away from the house and see if water will actually absorb into the dirt some 10 or 15 ft away from the house, If it does you might be good with a drywell


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## SPS-1 (Oct 21, 2008)

JSDNJ said:


> 1-Dig out the soil a couple feet away from the foundation, place cloth, perforated pipe, clean stone along the foundation to carry the water away to daylight in the front. This will not correct the grade, but will hopefully carry the water away instead of pouring over the sill.



Sounds like a plan, so long as you have a low area to drain to.


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## 3onthetree (Dec 7, 2018)

I have to assume the normal reaction and say "that's pretty bad." So only relying on a french drain when other opportunities exist is just a bandaid. A drain next to the foundation, just within a couple feet, can and will be overwhelmed eventually, or frozen, or rooted. 

You are below the neighbor who's on a hill, but still have a place to daylight a drain. Then you really need to extend the slope out at least 8' to 15' with a swale to the lower daylight spot. Don't even let the majority of water get within 2 feet of the house, attack it as far away as you can with the french drain at the swale (if it would even be needed there). You didn't say how deep you'd have to go, but any spoils can be used to create a berm stopping the sheet flow from the higher neighbors. I didn't understand how regrading creates a pit, but if you can regrade the entire lot, then better. 

Also, remove or relocate those bushes away from the house.


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## JSDNJ (Jan 2, 2017)

3onthetree said:


> I have to assume the normal reaction and say "that's pretty bad." So only relying on a french drain when other opportunities exist is just a bandaid. A drain next to the foundation, just within a couple feet, can and will be overwhelmed eventually, or frozen, or rooted.
> 
> You are below the neighbor who's on a hill, but still have a place to daylight a drain. Then you really need to extend the slope out at least 8' to 15' with a swale to the lower daylight spot. Don't even let the majority of water get within 2 feet of the house, attack it as far away as you can with the french drain at the swale (if it would even be needed there). You didn't say how deep you'd have to go, but any spoils can be used to create a berm stopping the sheet flow from the higher neighbors. I didn't understand how regrading creates a pit, but if you can regrade the entire lot, then better.
> 
> Also, remove or relocate those bushes away from the house.



Here are a couple more pics that may make everything clearer. 





















I dont know if the yard is deep enough to correct the grade with a swale without rendering the yard useless. Bushes will definitely be moved btw.


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## MTN REMODEL LLC (Sep 11, 2010)

I would think of a french drain network thru the yard targeted at your collection areas and install an external sump pump to the street or wherever you can legally direct runoff.

Perhaps a swale that provides positive drainage away from the immediate foundation coupled with the french drain network. Perhaps you could use flagstone or some impervious stepping stone formation directly up to the foundation to immediately direct rains away from the foundation and into the swale and eventually into the french drain system.

There is a 1950 subdivision in Tiburon Ca that has the exact same issue. The network of french drain is configured carefully with collection zones, or slight/moderate swales are created as collection zones.

There is a fair degree in trenching and landscapeing, and installing mechanical/electrical sump pits.....but it works if you can not establish natural drainage..


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## 3onthetree (Dec 7, 2018)

Your backyard may seem level, but even a 1%-2% slope isn't very visible with undulating grass, fences and plantings, or even felt walking on it. But the water from the neighbors is seeking low ground at the street, with your house in the way, so you just have to direct it around your house. Whether you reslope or install pipes, you need to read these existing grade elevations. If you don't have a transit or laser level, you can check some spot elevations with just $10 worth of mason line, a line level, and 2 rebar stakes. 
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You have a perfect scenario to fix the problem (lower front yard, a place to dump water), it justs depends on how much earthwork you want to do:

1) The best solution is to regrade the entire yard. Starting 4"-6" below top of foundation, slope down about 1/4" per foot out 25' towards the fence (that's only about 6" of fall). Build a berm along the fence the remaining 5'. If the front yard is still below this 6" depth of the new grade near the back fence, you're golden. This lower grade elevation would then continue sloping down around the house, past the sides and meet up with the natural grade at the front. I would bet that no french drains would be needed at all, and there really aren't any "swales" per se, just a sloping grade.

1a) Add a french drain to a re-graded lot for redundancy, for the entire length of back fence at the low point of the new grade. Its best to slope this pipe as well, but connecting to the existing PVC on the side of house will determine its exit elevation.

1b) When regrading the lot, the sides of the house will be a little steeper. If this is a problem, or if the front doesn't allow a lower back yard to drain naturally to it, then you can still regrade just the back into a sort of "detention" area. Then pipe the holding water away.

2) Leave grade as-is, install a french drain next to the house. That's a lot of water, and you want it out of there quickly, so sloping to the existing PVC pipe would determine how low you can bury it. Besides clogging, freezing, or roots, remember capillary action will help pull water from the back yard to your house more quickly. No major plantings should ever be installed along the house.

2a) Combined with a drain at the house, add another french drain along the entire back fence. Again, no plantings.
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Most people choose to just install a french drain because it seems easier and less intrusive (I'd bet you will too). But even with a trencher, there is lots of gravel and spoils to shovel, and long-term performance is questionable. With regrading, it's just some skidsteer work and resodding. But both will need preciseness in setting elevations, and conflicts with utilities worked out.


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## JSDNJ (Jan 2, 2017)

3onthetree said:


> Your backyard may seem level, but even a 1%-2% slope isn't very visible with undulating grass, fences and plantings, or even felt walking on it. But the water from the neighbors is seeking low ground at the street, with your house in the way, so you just have to direct it around your house. Whether you reslope or install pipes, you need to read these existing grade elevations. If you don't have a transit or laser level, you can check some spot elevations with just $10 worth of mason line, a line level, and 2 rebar stakes.
> -------
> You have a perfect scenario to fix the problem (lower front yard, a place to dump water), it justs depends on how much earthwork you want to do:
> 
> ...



Wow. 

MASSIVE thank you for taking the time to do all of this. I mean really, that is remarkable. 

I really appreciate it. I am inclined to do the grading, but I am afraid the existing fence along the back and the new fence I have on the sides (not pictured) and the 20 arborvitaes and shed I have along the back fence might make it a little more difficult. I like the line of thinking. I think the drain along the back will be the 'easiest' but I share your concerns about the susceptibility of them to fail.


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## ktownskier (Aug 22, 2018)

Another suggestion to ponder. 

You obviously have a lot to deal with. Sometimes you even have more water to deal with than you usually do. And obviously you need to move it from where it is to where it isn't.

Depending on how much effort and money you want to put into it, it can be done. 

The first thing you need to do is to catch the water. This is done by drain tiles as you are aware of. But they need to run into a series of dry wells buried deep into into your back yard on a bed of rock, surrounded by rock and covered by rock and geotextile before the soil goes back on top. The dry wells are connected together so that if one reaches max capacity, it flows into the next one and so on. Also, solid drain lines run from there to a discharge point away from the house. 

IF you watch one of the recent This Old House episodes, they talk about dealing with rain water and overflow as well as dry wells. It may be worth watching.


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