[gtomseeley]

We have a small backyard bldg we call the garden center, since I built it from a kit and I refuse to let my wife call it a shed, even though that’s what it is. It’s on a gently sloping grade, with one side on its foundation almost at grade and the back diagonal corner level with the entire floor, of course, but now about 12” above grade. So, there is plenty of slope for runoff.

Trouble is, surface runoff and/or groundwater is still causing the foundation and floor at grade to rot, over about ten years. So I need to redo part of the inside floor and I also plan to install a simple gravel free French drain around two sides, to the lowest point at the back corner. I can do the carpentry and I know how to dig and install the French drain. There’s plenty of room on our property for me to run the line well away from the back of the garden center and terminate it where outflow would not do any damage.

My question is: what sort of outlet should I put on the end of the drain? Should I use one of those green popup gizmos like my downspouts end in? Or something else?

 

[AllanJ]

Having the drain pipe come to the surface (while still sloping down towards the outlet) with no accessory cover is best. The opening must never be obstructed which a popup could do if it got stuck closed. The French drain pipe or weeping tile must maintain an air pocket of at least a third of the bore (cross section) area inside.

Another alternative is for the drain pipe to dump into a dry well but with a sump pump or gravity overflow so the the French drain does not overfill as described above.

Rain water on the surface should drain away of its own accord. It may be necessary to regrade the land around the foundation to achieve this flow.

 

[John in NC]

Run it out around the corner to the back, and if you have enough slope just an open pipe is OK. You can 'tail it off' so to speak with gravel around the pipe a foot or so before the end of the pipe and a couple feet beyond.
Watch the "French Drain Man" on youtube, pretty good stuff. Apple Drains will pop up too as a counterpoint of what not to do, in most cases.

At the end of the open pipe there are some critter guards if that's a concern.
Pop up is a no for me.

Nice wide trench, line the trench with non-woven geotextile fabric, put the corrugated drainage pipe in, at or near the bottom, lots of stone, wrap the fabric around the top, pin it down, add some soil if you want over the top layer of fabric or just more stone or mulch.

Around that back corner low spot when the pipe comes to daylight that's where you can 'tail it off' which isn't a true technical term, but the pipe surrounded by gravel, pipe continuing it's downward trajectory/ slope, going to daylight is the best way to assure the water is removed, again assuming you have enough fall.
I have a flat yard, I'd pay good money for 4 feet of elevation around the house to the back and front property lines (100x200 lot), I probably have 10 inches of fall if that, a big problem. Crawlspace dug below grade too, fun! 1968 brick ranch.

Street holds water out front, drainage ditch holds water out back- limits my options bigtime!


PS in your case gutters along the front (high) 2 sides would be cool running to a rain barrel with an overflow going out to the low spot.

 

[3onthetree]

Either pop-up emitter or screened cap. I like the emitters because if there are any leaves/junk (although just a french drain you shouldn't have to worry about that) they just wash out of the end without getting caught on the screen. If it's on level grade it's ok to inadvertently step on it, or keep kids from jamming sticks through a screen.

On a daylight with a good slope, I install a 22.5d or 45d EL to better match the slope.