Retaining wall calculator

Set the first row on a level, compacted crushed-stone base and bury at least one full row unless the block guide requires more. Enter only the wall height that will remain visible above grade.

Plan a drain pipe for reinforced walls, walls over about 4 feet, poor-draining sites, paved areas, slopes, and tiered walls. Give the pipe a clear outlet and still use drainage stone behind the blocks.

Use clean, free-draining wall stone in the block cores and drainage zone, then compact approved soil behind it in shallow layers. Keep topsoil, organic material, and heavy wet clay out of the load-bearing backfill zone.

Use geogrid only when the block chart or wall design calls for it because of wall height, soil, slope, or weight above the wall. Follow that design for grid length and layer spacing instead of guessing.

Enter each tier separately, then compare the spacing with the lower wall height. As a starting check, tiers spaced less than twice the lower wall height apart should be reviewed as one wall system.

Check local permit rules before excavation. Get design help before ordering when the wall is tall, tiers interact, water has no clear outlet, soil is weak, or a slope, driveway, fence, structure, or property line is close.