Page 1 of 1

Posted: Mon Mar 12, 2018 2:17 pm
by mbjg0788
I have a large patio in my back yard that continues around one side of my house. There is water intrusion in my laundry room. I intend to install a french drain under the pavers along the rear wall and adjacent to where the block meets the footers. So I will have to remove some of the existing pavers. My first question is whether I should remove all of the pavers or just the amount needed to install the french drain. If I just remove the pavers needed to install the french drain will it be easier to reset the pavers than if I removed them all?
Next, I plan on putting geo fabric in the french drain trench then lay two inches of stone on the fabric, then put in the pipe and cover the pipe with two inches of stones and wrap the fabric around the top of the stones so they are not exposed to any dirt or other substance. My next question is what should I lay on top of the fabric that covers the stones and pipe. Should I put more stones, then 1" of sand on top of the stones and then the pavers on top of the sand? Or, should I put the soil that came from digging the trench on top of the fabric with 1" of sand on top of the soil and then the pavers on top of the sand? Or should I use something else (like paver base) to go below the sand and on top of the fabric that is wrapped around the stones and pipe?
This is my first french drain. So any advice you can offer would be appreciated.
Thanks much,
John

Posted: Tue Mar 13, 2018 9:59 am
by Tony McC
That's not a French Drain (which were obsolete a century ago!) - it's a filter drain, or, possibly, a fin drain.

Have a look at the land drainage page for basic construction guidance.

If you are placing such a drain against the sub-surface masonry of the house, you can either leave it open, maybe with a decorative stone top dressing as shown on the page referenced above, or re-pave over it.

Leaving it open requires you to re-create a retaining edge away from the building, which isn't difficult, but is an additional, unnecessary task. Re-paving over it relies on you getting good consolidation of the filter drain (not difficult) and then using the building itself, once again, to provide the retaining edge.

I know which I'd choose!