# Do I need drainage behind my retaining wall



## rakaschm (Aug 18, 2009)

I'm building a stacked block retaining wall. Wall will be about 14" high (3 4" courses plus 2" wall cap) above grade, with base course below grade, and about 60ft wide across the back of my yard. Wall isn't retaining a hill, just a raised level planter area with fence on top between us and the neighbor in the back. Wall is about 3 1/2 ft from the fence on my side. Similar situation on the neighbor's side. Also, we don't get a lot of rain here, something like 18"/yr. Do I need to bother with installing a drain pipe behind the wall, or is gravel backfill next to the wall and some landscape fabric to keep silt from coming through the wall adequate? If I need a drain pipe, what is recommended?

Thanks for your suggestions.


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## joetab24 (Apr 10, 2009)

what does the manufacturer's website say?

by no means am I an expert on this, but I don't think you do. my wall was 16" high and I am using 3/4" crushed stone.


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## Scuba_Dave (Jan 16, 2009)

Usually gravel back fill will do the job
Unless there is clay that will trap water
OR if you have a lot of rainwater run-off 

See this thread & Pic just posted
http://www.diychatroom.com/f16/major-flooding-51308/#post317080


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## TooledUp (Jul 7, 2009)

I dont think you would need any tile if you are not retaining a hill. The gravel backfill should work, but I would definately put the fabric in there. 
We have a boulder retaining wall and have been fighting the washout--we did not put any drain tile in(I recommended it to the landscaper and he didnt think it would be a problem). We however are holding up a hill. The landscaper did come back and put some fabric down and it helped considerably.


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