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Mortarless retaining wall - how big is necessary?

kyrral's picture

I am building a 4' tall, 45' long retaining wall out of mortarless block (the kind with the ridge along the back so they fit and taper gradually back). I am trying to find out if the smaller block would be ok for this purpose. Large block are about 16x12x6 and small 12x7x4. I think the only relevant variable would be the depth of 12" vs. 7". Big blocks are 68 lbs and small 22 lbs. I can handle the small but maybe not the big. The purpose is to backfill some some cabin land to gain more usuable space. San Bernardino county only allows a wall 4' tall to be built without a permit. After I build the 4' wall I intend to build another 2' wall a foot or so inside the first wall because I really need about a 6' wall to level out my land. The wall will run about 2' away from a paved county road.

Question about a footing. I don't think I need a deep one. I was planning on building about a 4" high footing about 2" into the dirt mainly to make sure the first course is level. Anyone see any prolbems here? Thanks in advance.

retaining wall (post #215533, reply #1 of 2)

Anyone see any problem here?

The biggest problem would be clearing it off the paved county road.

Get some real professional advice. Could be a bargin in the long run.

Keystone walls (post #215533, reply #2 of 2)


If you are talking blocks like those made by Keystone, the little ones with the ridge along the back are garden blocks and will not do for a 4' wall let alone a 6' wall. You will need blocks that lock together with pins and for 6' you will most likely need a geogrid fabric. No footing is necessary, but you need a compacted gravel base. If you study their literature you will find out exactily how to use these blocks. There are various options as far as size and weight. If you build 4' without a permit and then add 2' on top you will need a permit anyway. Get one. It shouldn't be too hard with the keystone literature.