Beginner Gardening: treated wood retaining wall, 1 by DaleTheGardener

DaleTheGardener wrote:
Good news and bad news.

A 3 foot tall retaining wall of any kind is probably going to fail (eventually) because of the soil pressing from behind (unless it is engineered-meaning expensive!). It will, however, take a few years to fail if you put gravel behind the new wall. That's the bad news.

If you build two smaller walls (18" to 24") and place one behind the other, in a step up fashion, they will last a long time if constructed with a good foundation and good drainage. This will require a lot of fill and truck loads of gravel for a 130' wall. The walls need to be 3' apart.

I got out the calculator and that is 29 yds (or 5 dump trucks) of soil to back fill a two wall set up. I won't scare you with the gravel figures, but, it would be less.

As I said above - you can go ahead with the block wall backfilled with gravel as you mentioned in your post. Just remember to give the new wall a good base and it should last you 15 or more years.

Here is a $16,000 set of walls with steps that I built in 2000 (I had a helper :-)