Retaining wall questions (construction, contractor, yard)

[GMS99]

We are thinking about installing a small retaining wall (2 to 3 feet high and 30 to 40 feet long) on our property. Our yard is at a fairly decent grade and we already have two higher retaining walls installed by the previous owner. This new one would be in a damp location (not swampy but shady and continually moist).

I'm toying with making this a DIY project but I'm also open to hiring a contractor. Any ideas on cost, construction, and time to complete? I'd prefer the wall to be masonry since even treated lumber has rotted out and been susceptible to insect damage in this area. The previously installed masonry retaining walls are over 10 yrs old and have held up very well with no apparent movement and no insect damage (like burrowing wasps).

[Kbinspections]

Use engineered retaining wall blocks and hire a mason.

[Mr.Malakalot]

If you don't know what the term "dead man" means in regards to retaing walls hire someone.

In my younger days I built many a reatining wall for Joe Graz construction. 5 feet high, 3 or four tiers.

if you removed some of your mason block wall you will probably find treated wood behind.