A house sewer shall be laid in how many inches of grillage?

A house sewer shall be laid in how many inches of grillage?

• A. 2 inches
• B. 4 inches
• C. 6 inches
• D. 3 inches

Answer: (B)

Grillage under a house sewer provides a solid, uniform foundation that spreads the weight from the backfill and structure so the pipe doesn’t bear point loads or settle unevenly. Four inches of grillage is the standard thickness because it reliably distributes loads and protects the pipe from movement or damage without unnecessary material. If the grillage is too thin, the line can crack or settle; too thick is wasteful. So the correct practice is to lay the house sewer on a four-inch grillage.

Grillage under a house sewer provides a solid, uniform foundation that spreads the weight from the backfill and structure so the pipe doesn’t bear point loads or settle unevenly. Four inches of grillage is the standard thickness because it reliably distributes loads and protects the pipe from movement or damage without unnecessary material. If the grillage is too thin, the line can crack or settle; too thick is wasteful. So the correct practice is to lay the house sewer on a four-inch grillage.