French Drain Specifications
French Drain Specifications
(OP)
Do civil engineering handbooks have basic french drain specifications? I would like to create a drawing to submit to San Diego City with a section view of the elements of a french drain. Any documentation available or a pointer to where I can find one would be greatly appreciated.
Cheers
Cheers





RE: French Drain Specifications
RE: French Drain Specifications
I specify a "socked" perforated pipe, AND lining the trench with filter fabric.
RE: French Drain Specifications
If you can avoid using filter fabric the French drain will perform better for a longer period of time. Ideally you want to use a sand/rock that will serve as a filter for the natural soil that you are draining. The permeability of the sand/rock should be at least double that of the natural soil. Second the holes in the pipe must be small enough not to allow the sand/rock to pass into the pipe.
With all of that said, yes you can just use a non-woven filter fabric between the natural soil and the sand/rock and between the sand/rock and the pipe. Good Luck.
RE: French Drain Specifications
On one of my parking lot projects we installed six (6)large french drains made from perforated precast pipe with a manhole cone section on top. Each drain is approximately 5' in diameter and 15'deep. They have been working for 20 years now and with some annual maintenence should continue to do so.
RE: French Drain Specifications
RE: French Drain Specifications
http://www.transit.govt.nz/technical_information/content_files/Specification8_pdfFile.pdf
RE: French Drain Specifications
Thanks for the help.
Al