This video shows a sharp cliff near my house that leads down to a stream. The drop is about 20 feet. I would like to build a 4' high retaining wall right around where you see a stack of dead branches. We'll be about 10' away from the stream and about 6' up. The wall would be facing SW.

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I have consulted with a contractor and he advised me that it's a bad idea to use treated railroad ties in an under a canopy of trees for fear of rot. However, I have a neighbor with a beautiful railroad ties retaining wall that's been there for 30 years and looks pristine. Furthermore, the lumber steps that you see are 75 years old and for 30 of those years were covered with leaves and overgrowth and the steps are still in passable shape.

What's your take on it? Am I safe using treated lumber to build a wall there?

  • 3
    Can you find regulations regarding using treated lumber or construction near wet lands? You might need to keep a buffer from the stream. – Mike Marseglia Apr 14 '17 at 12:41
  • Railroads pass under trees all over the world. They don't spontaneously rot or melt into the landscape. That said, I share the environmental concerns expressed by others. Ties are nasty. – isherwood Apr 14 '17 at 13:29
  • Extra info following the response and the comments: – Wynne Apr 14 '17 at 15:44
  • 1. The wall would be about 10' from the stream. 2. The house is being undermined. At the 7sec mark in the video, on far left you can see the wall under the path separating. 3. The cliff is currently a falling risk I'm concerned about which I'm aiming to address with the retaining wall. – Wynne Apr 14 '17 at 17:35
  • Isherwood, yes, wooden ties are used to support railroad tracks "under trees all over the world" but in a single layer and in a bed of gravel or crushed rock. They rot and have to be replaced on a schedule even in this application. When used for retaining walls they are filled behind. Constantly damp, they rot, crumble, are pushed by the force of the fill behind them onto a place where they encroach. – Jim Stewart Apr 15 '17 at 9:37

Where are you? Where I am from (Dallas TX) railroad tie walls rot and shift. And due to the wood treatment chemicals in the ties there are environmental regulations which limit disposing of rotted ties.

I would not bring railroad ties onto my property, especially near a stream.

In Dallas "gabion walls" https://en.wikipedia.org/wiki/Gabion are used by the city to control erosion around streams. First rate private walls are of special concrete blocks (http://www.versa-lok.com/ or http://www.keystonewalls.com/).

I would do nothing to this property unless the house was getting undermined.

If you would make a tall retaining wall, you will have constructed a cliff from which people (especially children) and dogs could fall unless fenced at the top. It would be astoundingly expensive and unless constructed by someone with real expertise they can start to shift and lean.

EDIT Building a 4' high retaining wall down near the stream would make a 4' drop-off at the stream. That would accomplish nothing positive, but would make a hazard there and interfere with stream flow under high water conditions.

EDIT #2 It is my understanding that the railroad ties commonly employed for "retaining" walls are used ties and are classified as "non-structural". These ties were removed from railroad beds and are re-sold for home landscaping. http://www.homedepot.com/p/Used-Railroad-Tie-Cresote-Treated-Common-7-in-x-9-in-x-8-ft-Actual-96-in-5100000070908000/100023488

| improve this answer | |
  • In Philadelphia – Wynne Apr 15 '17 at 3:52

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