Here is a diagram of what I am trying to achieve My patio is pretty much flat. Due to settling the water collects near the wall Since it is too much work to grade properly the entire patio I think that it would be good to rest the areas where the water collects and to add a french drain between the patio and the wall. The wall is presenting efflorescence due to too much water at the base. The water goes up on the wall due to capillarity pressure.

So ..what sort of can be used between the french drain and the patio (see the picture, the edge pointed by the arrow)

enter image description here


Someone on another site suggested something like this

enter image description here

  • Are you looking for an answer like "gravel"?
    – wallyk
    Oct 25, 2014 at 19:28

1 Answer 1


Here is an idea that might work for you... enter image description here

Here is a revised drawing added to the first one, with the idea you had given to you and I added where the various barriers need to be. enter image description here

I forgot to note in the drawing that the gray line is the filter cloth.

The full wrap of the plastic membrane will keep the excess water from migrating back to the house. Just placing it against the wall and the bottom will allow it to get to the walls still. Remember it will be a LOT of water concentrated there.

The plastic liner will act as an in ground gutter to move the water, so be sure the bottom is accurately graded towards a place the water can flow that will do the house no harm.

  • It may be better to place the heavy plastic between the 2x and the side with the sand and brick, locking it in with the paver edge
    – Jack
    Oct 26, 2014 at 4:41
  • Thanks Jack! Someone on another site suggested the solution illustrated in the image posted above in my initial message..What do you think about that? Your solution is interesting too but I am not comfortable with the idea of having the wood in there not even treated wood
    – MiniMe
    Oct 26, 2014 at 5:10
  • The wood blocks between the wall and 2x could be temporary, they are only there to hold the border parts inline until the gravel for the drain is in place. You will need filter cloth between the sand bed and the gravel of the french drain, otherwise it will wash down into the french drain. Otherwise, that is a great idea. I wish I had thought of it myself.... Are you aware you can post and approve your own answer here?
    – Jack
    Oct 27, 2014 at 2:29
  • Hi Jack Yes I am but I don't know if it is a good idea to do that since: -I am not the one who found the solution -others of this discussion board might come with another solution. I also think that this is discouraged by the forum admins, some would just love to get points although I don;t see their point :-)
    – MiniMe
    Oct 27, 2014 at 2:42
  • my drawing is not very clear, but actually the patio and the french drain will share the same gravel in that area where they intersect. I should have used the same colour. However you have a good point, in that area the sand might migrate downward through the gravel. On the same note, I can't understand why that doesn't happen where there is only patio, sand and gravel (no french drain) Whater is still coming from above..and it will end up mixing the two layers ...does that really happen ?
    – MiniMe
    Oct 27, 2014 at 2:47

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