#57 Stone (Crushed Granite) raised-bed Screened loam (the mineral base)

Screened loam (the mineral base)

but no surprise rocks or organic chunks that would interfere with seed germination or sod installation

and most insurance-rated playgrounds

5" Riverbed as the bottom layer with stones piled into shallow mounds at 4–6" depth

drains fast enough to play after a rain delay

#57 Stone (Crushed Granite) raised-bed Screened loam (the mineral base)#57 Stone (Crushed Granite) The Industry Spec Drainage & Concrete Stone #57 Stone is the named spec crushed stone every drainage installer, septic contractor, and ready mix concrete crew calls out by number. Quarried from native Boston area granite, angular, washed, and gradationally clean of fines, it drains fast, locks under load, and meets the ASTM C33 AASHTO M43 No. 57 standard called out on engineered drawings. If a plan sheet says "57 stone,"