PDA

View Full Version : French Drain Estimating???


sclk0907
04-23-2007, 01:03 PM
How do you estimate a french drain? I have a customer that needs one installed and I don't know what to charge. How do you figure your materials if you have never put one in before?

mverick
04-23-2007, 02:00 PM
Depends on size and depth.

Had a company here quote $5000 7 years ago for the front of a home. I just did one across the front of a home for $10,000.

Depth ranged from 5 feet to 9 feet and 16in trench. 20 ton of 3/4 clean. It was 70 feet long with a 30foot dig to drain down a hill.

Now comes the bigger job of landscaping the front yard after I destroyed it with the excavator and bobcat. That should be another $18,000.

Coffeecraver
04-23-2007, 05:12 PM
If you dig this by hand
16-23 dollars a ft includes materials --stone---4"corr.pipe and labor

Mike33
04-23-2007, 10:13 PM
They can get more expensive than you think but i have never done 1 for 10k yet. First you need to know how long and deep. If its across average back yard let say 40' long 2 ' deep catching surface water now.
Excavate: 2 hours
Load and haul away dirt 2.5 hours
Pref. 4" pipe
8 ton 57's
Install pipe and stone 2.5 hours
Clean up and repair damage areas 3 hours
Seed and mulch damage area
This is my average formula you figure your rates for labor and stone in your area.
Mike

sclk0907
04-24-2007, 10:01 AM
Do any of you use the landscape fabric?
I may be wrong but i've read to put down landscape fabric, then coarse rock, pipe, more coarse rock, then small rock, cover with the remaining fabric and put down sand and seed.
Does this seem about right?

Mike33
04-24-2007, 09:45 PM
Do any of you use the landscape fabric?
I may be wrong but i've read to put down landscape fabric, then coarse rock, pipe, more coarse rock, then small rock, cover with the remaining fabric and put down sand and seed.
Does this seem about right?

I do when i put a thin layer ot topsoil over stone and seed. I dont like putting soil over the stone due to it restricts the water from going in
Mike

tjsquickcuts
04-24-2007, 10:01 PM
I had a few lawns with drainage problems, and did a pretty quick fix that helped them dry right up. I cut up the sod, excavated about 18inches, placed drainage rocks in my trench, filled over the top with sand, then a little top soil, and placed the sod back down. Was early last year, and havent had any problems since. Not sure if you are having the same problem, but I needed a fix because I laid the sod, but the builder did the grading and builders will be builders, and he wanted the cheapest fix he could get.

Scenic Shrubs
04-25-2007, 10:54 AM
Depends how wet of an area/ what type of soil etc. They do make a "sock" (like fabric) that will slip right over the 4" pipe. Works pretty well. If the area is real wet. Dig the trench, lay geofabric or landscape fabric down the side bottom and up the other side. Place some rock on the bottom, lay the pipe, fill with stone. Lastly cover the stone with more fabric top dress with loam /seed. This is the most effective way to remove/ collect large amounts of water.

mdvaden
04-25-2007, 11:46 AM
This may be the first post in which I've ever answered by saying that if you are asking this question about a simple drain line, you should go to the supplier, see the parts in person, and make your own diagram and parts list.

Without complications, is may be among the most streamlined of procedures.

This is one that you should be figuring out yourself.

Formulas don't work, because we don't know how hard, wet or soft the soil is, whether you need to haul it or build a mound with it, or how much rock costs there.

Let me give an example to explain....

I never did a paver project - ever - in 25 years, until two months ago.

It was a 300 sq. ft. area. So, I didn't ask anybody on here how to bid it. WHY?

Because I need to measure the area. I need to find out the size of block, how much it covers, how much the delivery fee is, how much the tractor cost, how much the gravel was.

No formula needed. And no need to ask anybody. Because I have to make my own materials list and price-out each item.

forestfireguy
04-26-2007, 07:51 AM
We call these "curtain drains" and after the big noreaster a couple weeks ago demand for this kind of work has gone through the roof. We typically trench anywhere from 2 feet for a slab home to 8 or 9 feet for home with a basement. We line all trenches with fabric, then lay pipe. We also tie all of the downspouts from the gutters into this pipe. Water will follow the path of leastesistance and thus when ground water, or surface water hits the "curtain" (free draining 3/4 clean or larger stone) it drops to the pipe and flows where we want it to. The fabric is essential to the useful life of this type of drain, in certain soil types soil work its way into the stone and clog it, (same principle behind stone and fabric behind an SRW)we have removed old drains with out fabric lining to find them completely clogged with soil. We have seen this most in areas with a lot of shale, which around here is almost always mixed with very poor draining soil. Anyway for the cost fabric is worth its weight in gold.

mdvaden
04-26-2007, 12:35 PM
We call these "curtain drains" and after the big noreaster a couple weeks ago demand for this kind of work has gone through the roof. We typically trench anywhere from 2 feet for a slab home to 8 or 9 feet for home with a basement. We line all trenches with fabric, then lay pipe. We also tie all of the downspouts from the gutters into this pipe. Water will follow the path of leastesistance and thus when ground water, or surface water hits the "curtain" (free draining 3/4 clean or larger stone) it drops to the pipe and flows where we want it to. The fabric is essential to the useful life of this type of drain, in certain soil types soil work its way into the stone and clog it, (same principle behind stone and fabric behind an SRW)we have removed old drains with out fabric lining to find them completely clogged with soil. We have seen this most in areas with a lot of shale, which around here is almost always mixed with very poor draining soil. Anyway for the cost fabric is worth its weight in gold.

Glad you mentioned that.

I wrote about clogging on my drainage page, but rarely need fabric due to the way I angle the trench walls. But I never needd to go very deep.

For what you are mentioning, it makes a lot sense to use fabric to prevent the soil from disloding into the rock - rendering it almost useless.

I find that lime will do wonders too.

mverick
04-26-2007, 03:02 PM
:cool2: We call these "curtain drains" and after the big noreaster a couple weeks ago demand for this kind of work has gone through the roof. We typically trench anywhere from 2 feet for a slab home to 8 or 9 feet for home with a basement. We line all trenches with fabric, then lay pipe. We also tie all of the downspouts from the gutters into this pipe. Water will follow the path of leastesistance and thus when ground water, or surface water hits the "curtain" (free draining 3/4 clean or larger stone) it drops to the pipe and flows where we want it to. The fabric is essential to the useful life of this type of drain, in certain soil types soil work its way into the stone and clog it, (same principle behind stone and fabric behind an SRW)we have removed old drains with out fabric lining to find them completely clogged with soil. We have seen this most in areas with a lot of shale, which around here is almost always mixed with very poor draining soil. Anyway for the cost fabric is worth its weight in gold.

It's a little different here. The ones with the fabric block the fabric and you don't get drainage in them anymore. Rock is clean but the fabric is blocked so no flow. Even with fabric on a 8ft wall. Takes a couple years but that's what happens.

I dig them from 6-9ft slant so they have a down hill slope. Put in 2- 4in pipes and angle them out the back on walk outs or put in 2 sump pumps for in ground. One a little higher then the other in case one dies.

Curtain drain or French drain. They both work great. Keeps the water from getting close to the basement walls.

We incorperate it into our landscaping. Close to the house we use plastic and run it on top of those curtains with a pipe in it also. So no surface water gets into them. Surface water has it's own path. Curtain is just for the under ground water.

Our downspouts are in another solid pipe. I don't run anything into that trench.

They cost a lot of money though...:cool2:

sclk0907
04-27-2007, 08:23 AM
In West TN we have a lot of clay in our soil. Would it still be best to use the fabric?

mverick
04-27-2007, 08:37 AM
In West TN we have a lot of clay in our soil. Would it still be best to use the fabric?

Where I'm putting them it's all clay pretty much. Hard to dig once you get past 6 feet.

mdvaden
04-29-2007, 12:27 PM
In West TN we have a lot of clay in our soil. Would it still be best to use the fabric?

Do you think that the soil would collapse under weight over time?

Most of mine are shallow, and angle walled, so there is almost no collapse. If you go deep, it's hard to angle the walls without having a huge opening to fill.

About the only reason anybody needs to go deep, is to get through a small hill. But, in that case, there is no need for rock fill, nor perforated in the hill. I go through high areas with solid pipe many times, so fabric is irrelevant. And the rock would be irrelevant in the hill area. Soil backfill works in those areas if the pipe is solid or has a fabric sock.

Unless I'm trying to allow deposit of water in the trench itself.

In general, I only need to gather in shallow areas. And a French drain need only be 12" deep to do the job if its not clogged. The deeper a trench is, the more likely it is for some problems to occur.