Drainage Stone Calculator
Calculate the right amount of stone for effective drainage systems.
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Plan Your Project with the Drainage Stone Calculator
Proper water management is key to protecting your home's foundation and maintaining a healthy landscape. Our drainage stone calculator helps you estimate the amount of clean gravel or crushed stone needed for projects like French drains, dry wells, or backfilling behind retaining walls.
The key to good drainage is using a 'clean' stone—one that has been washed to remove fine particles and dust. This creates voids between the stones, allowing water to percolate through freely. This calculator is the perfect tool for ensuring your drainage system has the capacity it needs to be effective.
Frequently Asked Questions
What is the best stone for a French drain?
The ideal stone for a French drain is clean, uniformly sized crushed stone or gravel, typically in the 3/4 inch to 1.5-inch range. #57 crushed stone is a very common and effective choice.
How much stone do I need for a French drain?
A typical French drain trench is 1 foot wide and 1.5 feet deep. For every 10 feet of length, you would need about 0.56 cubic yards of stone. Use our stone calculator for French drain with your exact trench dimensions for a precise number.
Do I need to wrap my French drain pipe?
Yes, the perforated drain pipe should be wrapped in a geotextile filter fabric 'sleeve' to prevent silt and soil from clogging the pipe's holes.
What does 'clean' stone mean?
'Clean' or 'washed' stone means the aggregate has been rinsed to remove small particles, sand, and dust. This is essential for drainage applications, as the fines would otherwise clog the spaces between the stones and impede water flow.
How deep should a French drain be?
The depth depends on what you are trying to achieve. For surface water, 18-24 inches is common. To drain groundwater away from a foundation, the drain must be at least as deep as the foundation's footing.
Can I use pea gravel for drainage?
While pea gravel allows for water flow, its rounded shape is not ideal for locking in place. An angular crushed stone provides more stability and is generally preferred for drainage systems around foundations and retaining walls.