Joined: July 2004
||Posted: 13 Mar. 2018,10:59
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!
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