Replies

1. 
   BossHog | Oct 21, 2002 06:52pm | #1

   "do the two rows of holes orien up or down?"

   I've heard 2 schools of thought on this:

   First, you won't get as much sediment falling into the pipe if the slots are down.

   Second, the water will run faster on a smooth suface if the slots are up.

   Take your pick - I don't know which is right.

   The longest journeys start with the first step... and continue one step at a time.

1. 
   NormKerr | Oct 21, 2002 07:16pm | #3

   neither!

   use the perf pipe with the fabric sock on it.

   This way, silt that gets by the first line of defense is kept from clogging the pipe, and since there are holes all the way around the pipe water can get in any way it wants to.

   don't worry about the fact that the water that gets in at one point will 'leak out' before it gets to the drain because you are not trying to get a couple of cups of water away, you are providing a clear path for lots of water to get away so that it won't tend to go toward your house.

   Think of the whole french drain system as a big, dirty gutter, and the perf pipe in the bottom is the easiest way for the water to get out.

   I like to line the bottom of the french drain with plastic so that water won't tend to seep into the ground below it.

   the trench should ideally be filled as follows:

   - plastic to fill the entire trench (run it all the way up to the foundation and glue it to the house). Run this plastic all the way down the drain trench until you reach daylight.

   - perf pipe w/ sock

   - pea stone

   - silt fabric 'cover'

   - clay 'cap'

   - 4" top soil

1. 
   BillHartmann | Oct 21, 2002 08:05pm | #4

   How are you going to catch water run off if you cover the top of the trench with clay and dirt?

   Your design sounds right for a footing drain, but not where you want to capture surface water.

   After the top layer of fabric you can use some decorative rock or small gravel.

1. 
   user-178115 | Oct 21, 2002 09:09pm | #5

   Agree that in this instance, trying to intercept surface water coming from street, clay cap should be ommitted.  If pipe already purchased, then "typical" practice is to install with perforations facing down on top of a stone bed (with the 12" trench) already dug, you might be a bit tight for pitch here).  Admit, that an "up" versus "down" debate could probably become another "ridge" or "drip edge" wars...

   Regards,

   Rework

2. 
   EdJW | Oct 21, 2002 09:15pm | #6

   Bill, that's exactly what I did.  I filled the trench up with gravel then put some larger decorative river rock on the top.  I had a terrible surface water problem in front of my inground pool that was causing the pool liner to lift up.  When we would get a heavy rain the end of that 4 inch pipe looked like a fire hose.   I think puting any type soil on top would be a mistake.  -Ed

1. 
   NormKerr | Oct 21, 2002 10:58pm | #7

   oh, yeah.

   I forgot to mention that the surface should be sloped away from the foundation, with a good "swale" in the final grade to direct the majority of the surface water away naturally, to somewhere downhill and away from your building.

   Now, if your problem is that there is no "down hill" that you can direct such a swale to that you should keep the drain "open" on top (no clay / topsoil).

2. 
   ANDYSZ2 | Oct 22, 2002 01:50am | #8

   Don't use plastic it will hold up for about five years then start to disintagrate.I like using robber roofing that I get at home depots water garden  supply  area its expensive but it will last forever then I put about 4 inches of pea gravel on the bottom then my drain pipe wrapped in cloth sock then more gravel then landscape fabric then sand and soil mixed.

                                          ANDYSZ2

2. 
   EdJW | Oct 21, 2002 07:16pm | #2

   Judi, put the holes down. The water pressure in the trench will cause the water to go up through the holes in the pipe. You will also get less sediment in the pipe that may eventually clog. I have done this several times and it works well. -Ed

3. 
   gordsco | Oct 22, 2002 08:42am | #9

   I thought a french drain was just rocks, is there alot of water? Would just rocks take care of it?

   sometimes board sometimes knot

1. 
   NormKerr | Oct 22, 2002 06:51pm | #10

   I depends on what you are trying to do.

   just rocks will move a great deal of surface water, but eventually will collect surface debris

   covering with a clay cap and topsoil will allow you to grow grass, but as others have noted should be pitched to aid drainage of surface water

1. 
   JeffBuck | Oct 23, 2002 01:29am | #11

   down.....unless you used the all perf.......then make sure you cover the top with felt/fabric.......so the holes are still....down!

   plenty of gravel all the way around........and no plastic on the bottom!

   Jeff..............Al-ways look on......the bright......side of life.............