Replies

1. 
   hammer1 | Oct 29, 2004 05:23am | #1

   In my area we use 3/4" crushed stone as a bed and back fill. Flexible, black, perforated 4" pipe with silt cover. It comes in big rolls. If additional gravel fill is used on top of the stone, we use a geo-textile to help keep materials separate.

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1. 
   Toolfool | Oct 29, 2004 03:37pm | #3

   Thanks for the response... help a simple man know what a geo textile is?  I was going to have a slight bed of stone the pipe and cover with the same stone, like a burito.... all in a ditch about 1 foot wide just inside the foundation wall.  Do I need to be real accurate on my pitch to sump

1. 
   hammer1 | Oct 29, 2004 06:44pm | #4

   Geo-textiles are fabrics that are made for various landscaping and construction jobs. There are a wide variety from the black fabric fences you commonly see surrounding the edge of construction sites to weed blockers for the garden.

   French drains don't need a whole lot of pitch. Generally we start at the far end from the collection box. The depth of the box or the connection to the positive drain is the low point. If I can get an inch of pitch in 40 feet that's fine. Just make sure there are no sags or low spots in the pipe. It should be straight.

   Over time, fine particles wash down and can accumulate in the drains and block them. That is why we use a silt cover on the pipe. The same thing happens to the crushed rock. The fabrics can be expensive so I'll use what ever I have on hand. Used silt fence, if in good shape, will work fine. You may be able to get it for free if you pick it up for the contractor after a job. Not everyone uses a fabric over the stone. It would take many years for this to become a problem, if ever, but that also depends on the soil.

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1. 
   Toolfool | Oct 29, 2004 08:50pm | #5

   Thanks so much for all your advise.  Any specifics on the catch basin where the sump pump goes.  There happened to be something that looks like a bottomless bucket with a bunch of holes in it.... it was just sitting down in my crawl space.  I figured just surrond that with gravel and exit the corrugated pipe into it.  ANy advise there or better strategy

1. 
   gdavis62 | Oct 29, 2004 10:57pm | #6

   The places that sell drainage tile usually can offer it socked with the filter fabric.  That gives you a total wrap.

2. 
   hammer1 | Oct 30, 2004 01:21am | #7

   Over time french drains can get a little stinky. Most pipe supply houses sell specially made plastic basins with covers. They have holes for a sump pump. I like to keep the pumps off the bottom a little so they don't suck any sand. Makes for a neat job. The bucket is placed to come flush with the slab. Some have holes for your drain pipe, some you have to cut. You can position to suit site conditions. It's hard to collect unwanted water if the bucket has no bottom. In some critical situations we use a battery back up sump pump. There can be some sites that always have water running and a power failure would mean flooding. I guess you must have some water problems or you wouldn't be putting in drains.

   A positive drain, one that can deposit collected water to a lower part of the property by gravity, is usually a better choice than a pump. If you have a place that is lower than the french drains nearby you can pipe there. In this case we run solid pipe from the collection box to the location. No need for rock or silt covers on the solid pipe. Some zoning laws are strict about where water can be pumped or drained.

   The fabric I mentioned before, over the crushed stone, is for exterior french drains. You won't have soil washing down through the backfill on interior drains. I would still use the pipe with the silt cover.

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3. 
   Toolfool | Nov 01, 2004 03:41pm | #8

   Thanks again for all your help.  I knocked the job out this weekend.  Took me all day saturday and half sunday.  Plenty sore back muscles and bruised knees. Still have to hook up the sump pump and put back down the vapor barrier.  Any other advise to getting the moldly smell out?  I've heard bad things about sreading lime.  I'm hoping vapor barrier will help as well as dryer overall crawl space.   I have noticed small amounts of mold growing in various places on the floor joists, any pointers there?  Truly grateful!

4. 
   hammer1 | Nov 03, 2004 04:38pm | #9

   Nothing like a weekend on the business end of a shovel. There have been a few posts concerning french drains lately and I forget your specific circumstances. There are several factors to look at when abating moisture. In my area we build on full foundations with concrete basement floors. French drains are placed around the perimeter of the building both inside and out. We slope the landscape to drain away from the house and gutters with downspouts direct collected water away. With gutters you also need to have good insulation and ventilation in the attic to prevent ice dams and damage to the gutters.

   You should try to kill existing mold. Wear full protective gear, goggles, gloves, disposable clothing. Fill a garden sprayer with 1 cup of chlorox, 2 gal water. Spray everything down as needed and carefully rinse with clear water. You have to be easy on the water if treating wood. Get the air circulating with fans. You can also pour some chlorox in the drain but it is very corrosive so make you don't get it on or in the pump. There are all kinds of desiccants that can be placed to absorb odor. Kitty litter, baking soda, coffee grounds as well as open pans of vinegar are some home remedies. Boat supply houses sell absorbers and there are many different types and brands.

   In dirt floor craw spaces, heavy plastic is often used to seal moisture from permeating up through and making it's way to your floor. The site below has some good info and some links that are advertising but also have good info.

   http://nyny.essortment.com/odorcontrol_rdjx.htm

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2. 
   JeffBuck | Oct 29, 2004 05:31am | #2

   btw ... those holes in the pipe ...

   they go down ...

   not up.

   Jeff