Oops, didn't realize this was a 6 year old thread. Good digging MariaD. For anyone else who may be interested, I just did about 14' of 8" retaining wall along with our 8" ICF basement wall pour(46 YDS total). I used 3/4" ply and 16"O.C. Crosstie spacing. Even with 3/4" I can see where it flexed/bulged with the Concrete pressure between the blocking. In hindsight, I should have used ICF. From a purely cost perspective to do the retaining wall in ICF, it would have cost me about $60 more. From a time perspective, with the ease of working with ICF, I coud have probably formed it up and added additional bracing to keep it in place with the main wall in probably 4+ hours. The wood formed wall took me the better part of 2 weeks working in the evenings and most of one weekend in the middle. Lots of cut and fit, lots of holes and lots of screws, and of course a bunch of tie wedges that I may never use again... The wood formed wall had the advantage of allowing me to gauge the consolidation of the concrete after the pour. I rolled used gegetable oil on the inside of the form the day before the pour. It didn't take very much oil and the forms came right off. This forum engine won't take my ipad photo format. Here is a link/address to a pic of the formwork on photobucket. http://i270.photobucket.com/albums/jj85/rmarlett/41715b9a1a8be766760342304ae8a421.jpg