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Weeping tile (French drain) access or cleanout?

neverperfect | Posted in General Questions on

I am installing a drainage mat in a small section around my foundation. While i am installing it, I am wondering if there is any real word advantage of creating a “clean out” or or inspection pipe that leads to the surface.


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  1. user-659915 | | #1

    Interesting question. I've never known it done, but foundation drains can and do get clogged over time and I could see the opportunity to blast them clear might be useful. The best protection though is to ensure through proper surface grading that silt-bearing water seldom if ever enters the system. Think of it more as a vent to prevent hydrostatic pressure on the foundation rather than as a drain for routine water intrusion.

    But why are you installing around only a small section of your foundation? In normal circumstances the whole perimeter should be so treated.

  2. neverperfect | | #2

    50 year old house
    i have a cold cellar (outside the cold cellar) which is very damp and has a garden in front of it. i figured, before planting the new garden, try to slow down the problem.
    i bought a drainage mat, not really sure if the surface needs new blueskin (there is tar from 50 yearso go.
    also considering putting a layer of 2" insulation

  3. GBA Editor
    Martin Holladay | | #3

    If you are talking about 4" perforated pipe installed alongside a footing (and leading to daylight): I have often seen cleanout tees installed, with risers to grade. This feature makes sense.

  4. neverperfect | | #4

    i just dug down, maybe 5-6 inches above the top lip. no weeping tile in this location. I know there are in other locations in the house, but not ouside the front porch which juts out. i guess no cleanout after all.

    I bought a drainage mat that that has no SPBO drainage channel in it. It's just a piece of PE
    With no drainage, i am concerned that installing a drainage mat will divert the water maybe to unwater areas. the soil was very mosit when i took it out.

    Should i not install the drainage mat?
    i also bought 2" XPS to install on the exterior. i don't even know if i should install that


  5. GBA Editor
    Martin Holladay | | #5

    If you have already gone to the trouble of digging down to the footing (or almost to the footing), you might consider installing perforated drainage pipe. However, you need to think about where to conduct the water -- whether to daylight, a sewer connection (if allowed by your municipality), a sump, or a dry well.

    There are advantages and disadvantages to installing rigid foam insulation on the exterior of a foundation wall. For more information on this topic, see How to Insulate a Basement Wall.

  6. neverperfect | | #6

    I managed to located the weeping tile that connects to the stormwater system only a few feet away. great!
    Should i buy 3/4" gravel for backfill the entire cavity exept the top 12 or 24" (ideal)?, or is reusing the old soil against the drainage mat sufficient (with gravel only at the bottom around the weeping tile? the biggest issue is what to do with the soil pile if i install the 3/4". some of the tar "stuck" to the clay, i don't want to spread it out over the lawn.

  7. GBA Editor
    Martin Holladay | | #7

    As you note, the ideal backfill material would be a granular, free-draining material like crushed stone or gravel. If you go that route, it's a good idea to install landscape fabric on top of the gravel to prevent clay particles from clogging the system.

    If you advertise "free fill" with a yard sign or a Craig's list ad, someone will probably come and take away your unwanted soil.

  8. neverperfect | | #8

    I have a questino about the connections.
    As you can see from this picture, in the yellow highlighed areas,
    should i be using a coupler? is that necessary?

  9. GBA Editor
    Martin Holladay | | #9

    The best type of coupling to use when connecting underground clay tiles and new plastic drain pipe is probably a no-hub coupling (a coupling using a black rubber sleeve that is held in position by stainless-steel clamps).

    When choosing what diameter coupling to buy, remember that a little too big is better than a little too small. For underground drainage of ground water, you don't need a watertight connection -- but you want a physical connection to keep the pipes aligned and to minimize the intrusion of clay and soil particles.

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