The corregated stuff is OK for agricultural drainage, which is what it was developed for. For intercepting and diverting water away from a structure you really should use rigid PE or PVC pipe with two lines of holes — installed at the 5 and 7 oclock positions in a filter of drain rock 12 inches wide and from 2 inches deeper than the pipe elevation all the way to the soil surface. Transfer to non-perforated pipe once past the structure and keep going downhill to lead the water to a suitable outlet.: What type of material should the pipe in the french drain consist of. Our french drain has a 4 black flexible perforated ribbed pipe. The holes are all the way around the pipe. Is this the way it should be? It seems that this will let the way out as easily as it lets it in, so what good is it? Help! My foundation wall is rising! Thanks
