Need some DEEP French Drains, how can I do this or hire someone?

[mvp76]

I agree with inveresk-also adding the fact that your downspouts should be connected to a solid drain sytem to get them relieved away from your house and foundo.
Try cutting a surface drainage swayle at least 4 feet away from the house making sure you have gravity flow from your high point on out and around the house first. then wait for the next good rain so everything gets good and saturated ,making sure the swayle is working properly. At that time crawl under your house with a flashlight and check the footings. Look for any areas that appear to have water running or seeping through the foundation.hopefully there wont be any and your problem is solved ..If there is water - french drain time, But in my opinion, and ive only been doing this stuff for 30 years, Your french drain only needs to be about a foot or 2 below your footings to start-your trench should have some fall to it - even 1% is ok bed about of foot of 1-3" drain rock all the way down the trench-then take landscape fabric the fiberous kind that is heavy duty and line the inside of the trench with this stuff,install your perforated pipe with the holes at 45* angles on each side (or use the flex ads pipe which has holes all around it).carefully backfill more drain rock over the pipe (about a foot) take the leftover fabric and wrap it over the rock you just backfilled and complete the backfill process with drainrock up to the desired grade.Basically your making a gravel burrito underground with a pipe channeling through the middle. the fabric is needed to filter out dirt and debris so the pipe stays clean and can drain easily. Simple huh?

 

[mancho]

Thank you everyone for your great insight and opinions.

Well, I have been dropping in on my neighbor with the 9 foot french drains and plastic sheeting walls to prevent moisture to get under the foundation.

BTW< these are post tension slabs, so there isn't any crawling under the house like my old wood pier home built in 1939 for $7,500. THis was built in 1999 with a much different slab of course.

Here is some news, I found out last year, my neighbor to the WEST, and DOWNHILL from our home, had this same "Extreme French Drain" system put in... get this, NOT 9 foot, but 14 FEET DEEP! YIKEESS!! I was speechless.

I said, isn't that overkill? Not according to the engineers. My neighbor said they took soil and water samples and while I do not have solid evidence, they say it's DRINKING WATER!!! wow no shock I guess...

I am hearing bids of $40K to $80K. good lord.

I went ahead and took some pics of the neighbors extreme 9 foot dig:

 

[2manyrocks]

Or the land surveyor who laid out the lots.

Great idea. The name of the surveyor should either be in the legal description on your deed or if they recorded a plat of the subdivision, it should be on the recorded plat at your register of deeds. The recorded plat would also be referenced in your deed.

 

[mancho]

I went back to the last year terraserver documented and it was the years after the property was built 1999. Terra had 2001 I think.

So I have the plat and I can post that but what am I to learn from the land surveying? That were on a hill? You think he has anything regarding useful information for me?

Maybe im clueless but it seems the development of this area was private .... still unincorporated... so the private developers could of done anything. Would I normally have access to that info?

 

[California]

The surveyor may recall walking the area.

If your lot was the drainage channel downhill from a spring he will probably remember that, and show the spring on his internal maps.

The surveyor who laid out the buried electric mains may have had to plan around the excessive water. He might have some insight and advice, too.

I have learned a lot talking with surveyors. They may be the only link to what was there before development. And they may talk more than individual builders who bought the finished lots.

I think the more clearly you can define the problem, the better your solution will be.

 

[Egon]

Did you take note of the type of soil in the neighbours trench?

 

[TonyF]

Hmmm, while I agree a big machine might wack the foundation... and that can't be good for anyone, I have not considered back pressure.

Specifically if the backfill isn't ... er, what? Right weight? If I'm removing heavy clay and putting back river rock and just a half a foot of sod/dirt, what additional pressure is achieved?...

The damage usually comes from bad technique during back filling when its close to a foundation-- dump the fill back in the trench carefully with the bucket vice pushing it with the machine.

 

[dodge man]

A couple of thoughts.

1. If it is dringking water, you can figure that out. All drinking water that I know of has chlorine in it. This can be tested for and you should be able to figure it out. If it is a major leak, it costs a lot of money to treat and pump water, so they should want to fix it.

2. Groundwater is a weird thing, it can follow different layers of the soil and pop out in strange places, so your situation isn't unusual. French drains do work well, but you have to have a place to outlet them.

3. I am a land surveyor and work for a civil engineering and land surveying company. When we design subdivisions, we always perform a topographic survey of the area before we start. We use this to design the roads and layout the lots. Like someone else suggested, this may help you see what the land looked like before hand.

4. I worked on a project this last fall, and it was houses that were sliding down a hill due to too much groundwater. A french drain was installed to help this situation. I don't know if we will know if it helps or not for several years. We had a wet spring, and that caused the problem, like it has in the past. We won't know the results until we have another wet year. I don't see why a french drain needs to be installed that close to the house, but I'm not an expert in the area.

5. Like someone else mentioned, one engineer said adding water during dry times may help. I know you don't like the answer he gave you, and it goes against your gut instinct and what the neighbors are doing, but don't dismiss his findings. He is suppose to be an expert and maybe he knows what he is talking about. It's also a very cheap solution.

6. The important thing to me seems to figure out where the groundwater is coming from. If its natural,you have to deal with it. If its coming from a watermain, you shouldn't have to deal with it. The water company should deal with it. The project I worked on the homes had severe displacement, several inches. During wet years it kept reappearing. I would think your situation is similar, it won't get better unless action is taken. Our bill for the surveying was over $1000. I'm guessing the bills to fix the homes and put in the french drain was over $100,000. Not all the owners participated, so I'm curious what will happen the next wet year, if the french drain will help some of the other owners or not. They drilled wells, took soil borings, and had some soils experts and geologist look at the problem. A $400 report might not cut it.

Good luck and I hope I helped a little bit.

 

[mancho]

A couple of thoughts.

1. If it is dringking water, you can figure that out. All drinking water that I know of has chlorine in it. This can be tested for and you should be able to figure it out. If it is a major leak, it costs a lot of money to treat and pump water, so they should want to fix it.

2. Groundwater is a weird thing, it can follow different layers of the soil and pop out in strange places, so your situation isn't unusual. French drains do work well, but you have to have a place to outlet them.

3. I am a land surveyor and work for a civil engineering and land surveying company. When we design subdivisions, we always perform a topographic survey of the area before we start. We use this to design the roads and layout the lots. Like someone else suggested, this may help you see what the land looked like before hand.

4. I worked on a project this last fall, and it was houses that were sliding down a hill due to too much groundwater. A french drain was installed to help this situation. I don't know if we will know if it helps or not for several years. We had a wet spring, and that caused the problem, like it has in the past. We won't know the results until we have another wet year. I don't see why a french drain needs to be installed that close to the house, but I'm not an expert in the area.

5. Like someone else mentioned, one engineer said adding water during dry times may help. I know you don't like the answer he gave you, and it goes against your gut instinct and what the neighbors are doing, but don't dismiss his findings. He is suppose to be an expert and maybe he knows what he is talking about. It's also a very cheap solution.

6. The important thing to me seems to figure out where the groundwater is coming from. If its natural,you have to deal with it. If its coming from a watermain, you shouldn't have to deal with it. The water company should deal with it. The project I worked on the homes had severe displacement, several inches. During wet years it kept reappearing. I would think your situation is similar, it won't get better unless action is taken. Our bill for the surveying was over $1000. I'm guessing the bills to fix the homes and put in the french drain was over $100,000. Not all the owners participated, so I'm curious what will happen the next wet year, if the french drain will help some of the other owners or not. They drilled wells, took soil borings, and had some soils experts and geologist look at the problem. A $400 report might not cut it.

Good luck and I hope I helped a little bit.

Yes, this is good info. Every bit helps! I have talked with several other neighbors here and it comes to down to this:

- The 14 french drains across the street did NOT level the house. wow

Spending 60K on 14 foot french drains doesn't level the home... nothing will but piering it up IMHO.

They have now had 3 years (this april) and still have heaving.

We KNOW NOW that it's NOT utility water, so thats out of the question.

I also now realize, I need VERY SPECIFIC water mapping to determine exactly where the water source it, and it's UNDER THE HOUSE, not from topsoil/rain water coming down the slight hill ... yes, I do want to correct the poor grading around my house, but that's now a secondary issue.

So, I will hire a company that has been recommended by a good neighbor and we will get the exact testing by engineers to determine:

- the soil type (backfill, clay, etc)

- the "potential" maximum expansion of the soil under the house.

- the predominate water source that is causing the extreme heaving on the NORTH side of the home/property.

I have heard from several neighbors as I continue to investigate, some folks piered the entire home, only to find the clay kept expanding and still heaved up the home, and they have to pier it even higher.

The neighbor across the street with 14 feet drains, actually had piers too on the "non heaving side", but didn't lift the house high enough... the piers as she recalled, were over 22 feet deep to hit something solid. Also, she told me as the french drain company keeps coming out year after year to continually work on the never ending problem, they discovered that some of their under-house water was moving UPHILL, ... so that is a factual process, not something made up.

I do like the concept of going back to the surveyor, (I identified him) but thats 15 years back, and while he can provide the topology mapping, it's just "cute" information, as it might or might not be inline with my heaving area. Not sure how much insight seeing 100 year old tributaries on a map is going to really confirm or just entertain me to a limited extent.

So, what I'm faced with is simply getting to the source of the water, which at this point rules out water from up a hill. Stand by french drain companies.

I think I would love to purchase a "horizontal drilling" machine (on craigs list for only 25K! at 4000 hours!) and I could just drill horizontal tubes under my house every 4 feet... and let those drain all and any future water. Of course this is a fantasy, but it would ideally make a "drainage" grid that would catch a big part of any water coming up from the ground. Ahhh the mind has a powerful imagination!

So, onward, I'm getting the engineering firm out in a week or so to start a real-deal analysis of the situation.

The french drain folks will have to wait until I get "rock solid" evidence of what is happening. No pun intended!

Thanks for reading my long posts and keeping up on thoughts and opinions. Every bit helps. That engineer / foundation forum I posted on has no responses, so I'm getting much more insight on this board.

 

[Egon]

Have you considered selling?