Retaining Wall Block & Geogrid Reinforcement Calculator
Calculate retaining wall concrete blocks, geogrid reinforcement roll layers, 3/4-inch drainage gravel backfill tons, and buried leveling pad depth.
Calculated Results
Frequently Asked Questions
When is geogrid reinforcement required for retaining walls?
Generally, any segmental gravity retaining wall exceeding 3 to 4 feet in height requires horizontal geogrid reinforcement layers embedded into compacted backfill soil to resist lateral earth pressure and prevent catastrophic wall overturning.
How deep must the retaining wall base course be buried?
As a rule of thumb, bury at least 1 inch of block for every 8 inches of wall height, with a minimum burial of 6 inches (one full block course) below finished grade to prevent toe blowout.
Why is clean 3/4-inch crushed gravel required behind retaining walls?
Clean gravel acts as an open drainage chimney that prevents hydrostatic water pressure buildup behind the blocks. Saturated clay soil expands and exerts thousands of pounds of pressure, which is the #1 cause of retaining wall failure.
How much geogrid embedment depth is necessary?
Geogrid length behind the wall face should extend at least 70% of the total wall height (e.g., a 4-foot wall requires geogrid sheets extending back at least 3.0 to 4.0 feet into the retained slope).