Site grading + drainage: 6 in fall in first 10 ft, swales OR drains at uphill side, downspouts ≥ 5 ft from foundation

Description

Site grading rules: positive slope away from foundation on all sides — minimum 6 in fall in the first 10 ft (5% slope), continuing at least 2% beyond. Uphill sides of buildings should have a swale or French drain to divert surface water around the structure. Downspouts should discharge ≥ 5 ft from the foundation (preferably 10+ ft) — via splash blocks, extensions, or storm-sewer connection. Plantings ≥ 12 in from foundation walls (prevents root + moisture issues).

Why this exists

Site grading sets up everything else in the foundation moisture story. Architects working with civil engineers should review the grading plan against the foundation plan to confirm every side drains away — most lot drainage failures come from a single low corner that ponds water against the foundation.

Categories

Source

Solver enforcement

Browsable only — the solver does not currently enforce this directive (no spec-level data to check against). This entry exists so the architect personas can cite it in conversation and the user can read what the rule says.

Related directives

• Continuous load path from roof to foundation · HUD RSDG §2.4
• Residential structural reliability targets 1-in-100 to 1-in-1000 annual probability of failure · HUD RSDG §2.5
• Residential floor live load: 40 psf minimum (30 psf sleeping rooms) · HUD RSDG §3.4
• Wind load design uses ASCE 7 basic wind speed for the locality · HUD RSDG §3.6
• Ground snow load for Virginia: 25 psf eastern, up to 40 psf western mountains · HUD RSDG §3.7