A retaining wall is holding back soil and water, and it is almost always the water that takes it out. Drainage behind the wall is not an upgrade, it is the wall.
Gravel backfill, drain rock, filter fabric and a pipe that actually goes somewhere. Anything over four feet generally needs an engineer and a permit in this county, and we will tell you that rather than build it and hope.
Poured walls where the look matters or the height needs it, block where it suits the site and the budget.
Drainage
Drain rock, filter fabric and a pipe with an outlet
Over 4 feet
Engineering and a permit, generally required
Types
Poured concrete or segmental block
Backfill
Compacted in lifts, never dumped in one go
Where we do this work
Retaining Walls across the whole valley. If you are in one of these, Heath will come and look at it.