Hi all,
I have grade that draws surface water towards one side of the home. The asphalt on the right of the picture is sloped slightly towards the house. The left side (below the black geotextile) is a mix of dirt and crushed stone. At the left edge of the asphalt there is a shallow french drain (red line in pic) that goes to the ditch. I put the geotextile down with the plan of putting 0-3/4″ crushstone over it sloped towards the drain/asphalt, away from the house. After getting a bit of rain just now, I notice that it’s less permeable than I expected and I worry that any water that seeps through the (to be added) crushstone will settle on the fabric and run towards the house.
Do you think this is a real concern? Building up before geotextile would be challenging since the layer will be only 1-6″ thick and I’d likely end up with exposed fabric.
Replies
Lower the drain to ditch?
Hi, thanks for the response, but I think I got the drain as low as possible while maintaining a 2% slope all the way. I think I might have not properly explained my concern, see the image I attached to this comment: blue line is the 0-3/4 I plan to put in, sloped away from house to the drain. Yellow line is to show the geotextile's slope towards the house. I think the real question is "how much water will get through the compacted 0-3/4 and sit on the geotextile to eventually drain to the house?".
Do you know which kind of geotextile fabric you have? There are 2 (at least 2, but I only know about 2), non-woven and woven. The non-woven allows water to drain through, the woven type, not so much. Here's one explanation: https://www.eastgatesupply.com/blogs/articles/what-s-the-best-geotextile-landscape-fabric-for-draining-water-1
It's definitely woven just by looking at it, and we've gotten a bit more rain which accumulates a bit. I guess the real question is how much water will leak through the packed 0-3/4" gravel that will be over it, sloped towards the drain.
If it’s 0-3/4” gravel (or crushed stone, there can be a big difference between the 2 for drainage when it includes the very small fine dust, fines), I would say you may get run off on top. You can get whatever size screened stone or gravel you want. Personally, I would get a size that didn’t include fines. That dust is what will prevent drainage.
Do you see where you have the red line drawn? I would put in a deeper trench there with the geotextile, perforated schedule 40 4 inch diameter PVC pipe and clean crushed stone or crushed concrete with no more than 2% passing the 1/2 inch sieve. Slope from the house to the drain even if it is lower than the asphalt covered area. Overlap the geotextile and back fill so that you have at least 3 inches of cover. Then add grass or simply crushed material three or 4 inches thick. If you want to control weeds, put down a fuzzy geotextile that is thick. The home supply stores have material that is much too thin. Amazon has some expensive but thick free draining black geotextile that I used to retain sand fill while the jasmine ground cover takes over.
Stuff I got on Amazon, Very strong material.
Sandbaggy Non Woven 4 oz Geotextile Landscape Fabric
Thanks for the response! The red line is a drain similar to what you described (clean 3/4 within high quality geotextile surrounding a perforated pipe - I uses the corrugated for this though). I think I didn't explain my question well enough... See in the image I attached to this comment. The blue line is the sloped (away from house) layer of 0-3/4" I plan on installing. My concern is the slope of the geotextile (yellow line) drawing any water that leaks through the layer of 0-3/4 (to be installed) to the house.