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More footing drain clarification

Joe Norm | Posted in General Questions on

About to lay my footing drain. Level and at base of footer as recommended here.

I will use rigid PVC with the holes facing down. 

Question, does this pipe need a filter sock wrapped around it?

Also planning on gooping the foundation with waterproofing. Is it also a good idea to install dimple fabric in addition to this? If so, at what level does the dimple fabric start and stop?

Thanks

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Replies

  1. GBA Editor
    Brian Pontolilo | | #1

    Hi Joe,

    More important than the pipe having a filter fabric sock is that the crushed stone you set the pipe in is wrapped in filter fabric. The stone is there to promote drainage. You want to prevent it from getting clogged with soil.

    Here is an article that will help you decide if you need a dimple mat: https://www.greenbuildingadvisor.com/article/using-a-dimple-mat-to-keep-a-basement-wall-dry

  2. Expert Member
    Peter Engle | | #2

    The article Brian cited has a good overview. Adding a mat to a damp-proofed wall provides an extra layer of protection. Maybe not needed, but not terribly expensive insurance. If you do use a mat, it gets terminated at or near grade level and extends down to the footing drains. As Martin states in the article, if you do use a mat, it is very important to use a termination bar at the top to keep soil and other stuff out of the dimples.

  3. Jon R | | #3

    In this image, I would lap the under slab plastic (blue) in front of the wall foam - so that any water coming down the inside of the wall is directed under the plastic (vs potentially above the plastic where it can't drain).

    https://foundationhandbook.ornl.gov/handbook/images/Chapter%202/2-14F_no-cap.png

  4. Joe Norm | | #4

    Thanks All,

    So how exactly does the process go to install the rock, fabric and pipe? Does the fabric get put down, then rock, then drain pipe, then more rock around the pipe, then wrap the whole thing like a burrito, then backfill?

    thanks

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