1. What is Gravel for French Drain?

Gravel is essential for proper drainage in French drain systems. It provides structural support, prevents soil from clogging the drain pipe, and facilitates water flow to the pipe.

2. How Does the Calculator Work?

The calculator uses the following formula:

Where:

• Length — Length of the French drain trench in feet
• Width — Width of the trench in feet
• Depth — Depth of gravel needed in feet
• 27 — Conversion factor (1 cubic yard = 27 cubic feet)

Explanation: The formula calculates the volume in cubic feet and converts it to cubic yards, which is the standard measurement for gravel.

3. Importance of Proper Gravel Calculation

Details: Accurate gravel calculation ensures proper drainage function, prevents water pooling, and avoids unnecessary material costs.

4. Using the Calculator

Tips: Measure the length, width, and planned depth of your French drain trench in feet. Typical French drains use 6-12 inches of gravel (0.5-1 foot).

5. Frequently Asked Questions (FAQ)

Q1: What size gravel is best for French drains?
A: 1/2" to 1" washed gravel (often called "drainage rock") is ideal as it provides good drainage while preventing soil from washing into the system.

Q2: How deep should the gravel layer be?
A: Typically 6-12 inches, with at least 2 inches below and 2 inches above the drain pipe.

Q3: Should I use landscape fabric with the gravel?
A: Yes, wrapping the gravel in landscape fabric helps prevent soil from mixing with the gravel over time.

Q4: Can I use sand instead of gravel?
A: No, sand can compact and impede drainage. Gravel maintains voids for water flow.

Q5: How much extra gravel should I account for?
A: Add 10-15% to your calculation to account for compaction and irregularities in the trench.