According to HUD soil removal standards, how deep below grade should soil be removed and what backfill depth should be used?

According to HUD soil removal standards, how deep below grade should soil be removed and what backfill depth should be used?

• A. Remove 4 inches below grade and backfill with 6 inches
• B. Remove 6 inches below grade and backfill with 6 inches
• C. Remove 5 inches below grade and backfill with 7 inches
• D. Remove 6 inches below grade and backfill with 8 inches

Answer: (D)

HUD soil removal standards aim to reduce lead exposure by removing the top layer of soil most likely to be contaminated and then restoring the area with a clean soil cover. The prescribed approach is to remove six inches below grade and backfill with eight inches of clean soil. Removing six inches targets the surface soil where lead from deteriorated paint and other sources tends to congregate, especially in a child-accessible area. Lifting only a smaller amount wouldn’t sufficiently lower surface lead levels, while going deeper than six inches adds cost and disruption without guaranteeing a proportionate benefit. Backfilling with eight inches provides a solid clean cap that helps prevent recontamination from shallow soil, maintains proper grade, and supports future landscaping or vegetation. A thinner backfill wouldn’t offer as much protection against re-exposure.

HUD soil removal standards aim to reduce lead exposure by removing the top layer of soil most likely to be contaminated and then restoring the area with a clean soil cover. The prescribed approach is to remove six inches below grade and backfill with eight inches of clean soil. Removing six inches targets the surface soil where lead from deteriorated paint and other sources tends to congregate, especially in a child-accessible area. Lifting only a smaller amount wouldn’t sufficiently lower surface lead levels, while going deeper than six inches adds cost and disruption without guaranteeing a proportionate benefit. Backfilling with eight inches provides a solid clean cap that helps prevent recontamination from shallow soil, maintains proper grade, and supports future landscaping or vegetation. A thinner backfill wouldn’t offer as much protection against re-exposure.