Perforated Drainage behind retaining wal
I have heard mixed reviews on puting a perforated drain behind a retaining wall. I have heard that a soil sock should be used and the holes in the pipe should be down. But I have also had experienced subs tell me the holes in the pipe should be up, and that a sock isn’t necessary. I cannot find the answer in the UBC or in any other publication so far. Does anyone know what is best or is it a matter of preference? Thank you!
Replies
i use a sock.. i put the holes down ... and i lead the pipe to daylight
If you put the pipe in stone larger than the holes in the pipe, you don't need a sock. If you put the pipe in sand smaller than the holes in the pipe, you need a sock.
There are certain soils where a sock is bad. Some soils are so fine the will clog filter fabric. In those cases it's better to not use it. Your local soils person at cooperative extension can look up the characteristics for the soil where you are.
wayne.. what keeps the fines out of the stone.. or..
what keeps the fines from migrating thru the stone and clogging the pipe..
we do both.. we sock the pipe, put the pipe in stone... and cover the stone with filter fabric...
and .. lead the pipe to daylight.. pitching all the wayMike Smith Rhode Island : Design / Build / Repair / Restore
pitching all the way
how the heck do you do that ?
especially on a big home ?
flex or rigid pvc ?
carpenter in transition
Put the high point in the center, pitch both ways. Flex or rigid
tim.. when i started i would look at these diagrams of footing drains.. i could never figure them out..
i mean .. once the water got into the drain.. where was it going?
anyways.. i did what i was told..
sometimes we'd dig them up.. like if we were going to put an addition on or something. they'd be full of water.. and why not.. where was the water going to go?
so .. i stated putting my footing drains inside the foundation.. and if there was no grade change on the property that would allow draining.. i'd drain them to a sump .. and then pump the sump .
i have very dry basements.. and our town has very high watertables..
same thing with french drains.. and perimeter drains.. and retaining wall drains.. if the pipe can't pitch and drain.. it's useless....Mike Smith Rhode Island : Design / Build / Repair / Restore
I have a client that is insisting that the holes be placed up. I do not want to do it as I think it is a mistake. Is there a standard publication that I can reference? I do not want to put the holes up. Is there a problem with using gravel and rock all the way to the top?
Thanks again
Keith
keith.. tell him the holes are designed to allow water to RISE in the pipe and drain the pipe..
if the holes are on the top, the water first has to rise ABOVE the pipe so it can drain..
if he wants the pipe to function 4" AFTER it could.. then you'll be glad to do it his way..
after all, he's paying the bill...Mike Smith Rhode Island : Design / Build / Repair / Restore
I'm sure there are references, but I'm sorry I don't know of them.
Thank you for your response. It has really helped.
Keith