We need to build a retaining wall near our pool area. We have not made final decisions on it, but it will be a minimum of 4' tall, and possibly 5' or more.
Many online tutorials recommend solid blocks with a back lip for walls up to 6'. These blocks don't require mortar or additional supports, and the lip makes placement very quick and easy. So I would love to use them.
However, when viewing these products on the websites of the two major home improvement retailers, the official response on all has been that these blocks should not be used for walls in excess of 2'. Said responses have also stated that any wall in excess of 2' tall should be engineered. So I'm unsure if they're saying their blocks cannot be used in a wall taller than 2', or if they're saying that they may work but are unwilling to take liability for that claim due to potentially poor installations.
So can these offset blocks be used to build a 4' - 6' tall wall if the wall is properly designed and constructed? Or would cinderblock with rebar supports be required?
In case these details are relevant:
- This wall will sit just off of our pool area patio, where there is currently a steep slope up to a gentle-sloping side yard
- The wall will likely be around 15' long, with a max height around 5' at one end and a height of 3' at the other end (the yard being held back is lower over there). There will be stairs at the short end leading up to the side yard
- I plan to dig 6" down for the first row of blocks, set on paver base
- I was not planning to pour concrete around the bottom row, but can if necessary.
- I plan to backfill behind the wall with 3/4" gravel over a 4" drain pipe, all enclosed in landscape fabric, with 3" of topsoil on top. Gravel filled and compacted after each row of blocks.