On Sunday, July 13, 2008 at 6:57:54 PM UTC-4, Percival P. Cassidy wrote:
Our railroad-tie retaining walls are collapsing after who-knows-how-many
years (here
they last in practice?

Perce

I recently made a trip to Los Angeles to see my daughter and her backyard was on about a 45 degree slope. It was torture to try to keep mowed and so she decided she wanted me to help her make stepped beds where she could use that land to grow her own vegetables, fruit trees and such. She'd already been to Home Depot and bought some of those cheap landscape timbers, the kind she thought were made of redwood but I assured her that they weren't. Anyhow, she had them stacked up on top of each other with a 3/8" rebar to hold them in place. I told her that I hated to hurt her feelings but that we'd have to tear out what she had done and start all over. She didn't really care since she was getting free labor.

So, we took down the first wall and I went to Home Depot and cut 10' sections of 5/8" rebar in half (5') and then drilled a hole with a new bit we had purchased at the end of each 8' long section of timber. Then I drove down to about 30" each of those rebars to hold them in place.

Next row I staggered the timbers so that I had a 4' section on each end with a 8' timber in the middles. This required that I drilled a new hole thru one end of each 4' section and on thru the first timbers thus glad I bought a drill bit that was about 24" long. Same thing with the next 8' long timber on the second row. Had to drill thru it and the timber up under it. Since there was already a rebar in the way I simply put the timber along beside the one that was already there and made a mark where to drill the existing rebar and did. When I was done all the way across there was 10 rebars for my 24' (3 timber) wall. We made it about 6 timbers tall and when we got them all on the rebars then I drove the rebars flush with the tops of the timbers and it's there for a good while. My only regret is I wish we would have used pressure treated landscape timbers instead of that stuff my daughter bought. In my experience, Yellow Wood sux but the kind of pressure treated lumber you can buy at Lowe's is great stuff. You can literally bury a piece of it for years and dig it up and clean it off and use it again. Only problem with their pressure treated is you need to put a proper sealer on it, otherwise it will start splintering and splitting and won't last too long because of that. Good luck!