Grade-change fill — fill-dirt body with a 4–6″ screened-topsoil cap, sloped away from the foundation
Don’t build a grade change out of topsoil. Bulk it 60–70% with compactable fill dirt, then cap the top 4–6″ with screened topsoil for a root zone. Grade must still fall away from the foundation — IRC R401.3 wants a 6″ drop over the first 10 ft (≈½″/ft).
What this diagram shows
A cross-section of a grade change built up next to a foundation wall. The bulk of the fill, about 60 to 70 percent of the depth, is compactable fill dirt built up above the existing subgrade. The top 4 to 6 inches is a screened-topsoil cap so grass and plants have a root zone, because topsoil is the organic, settling, expensive top layer and is not a structural fill. The finished grade slopes away from the wall, dropping 6 inches over the first 10 feet, about a half inch per foot, to shed water per IRC R401.3. The calculator routes the grade-fill project to fill-dirt density and reminds you to order a separate topsoil cap.
Topsoil Calculator
Free topsoil calculator with project depth presets for new lawns, garden beds & raised beds. Get cubic yards, tons, bags & a raised-bed blend split.