Landscape fabric is laid in strips that overlap at the edges. Enter the size of the bed or path, the roll width and length and the overlap; the calculator gives the strips and rolls to buy.
Landscape fabric formula
Effective width = roll width − overlap Strips = area width ÷ effective width, rounded up Fabric length = strips × area length Rolls = fabric length ÷ roll length, rounded up
Worked example: a 30 × 10 ft bed, 3 × 50 ft rolls, 6 in overlap
- Effective width: 3 − 0.5 = 2.5 ft.
- Strips: 10 ÷ 2.5 = 4.
- Fabric: 4 × 30 = 120 ft; rolls: 3.
Tips
- Lay strips along the longest side to reduce the number of seams.
- Secure the fabric with landscape staples along the edges and seams; the package usually suggests a spacing.
- Cut X-shaped slits for plants rather than removing large pieces.
- Cover the fabric with mulch or stone; the mulch and river rock calculators estimate those.
Questions
How many rolls of landscape fabric for 500 sq ft?
About 4 rolls of 3 × 50 ft for a 50 × 10 ft area with 6 in overlap.
How much should strips overlap?
Follow the fabric maker’s instructions; 6 in is a common choice.
Should fabric go under gravel?
It is commonly used under gravel and stone to separate them from the soil.
Sources
- NIST Guide to the SI, Appendix B.8: Factors for units listed alphabetically, National Institute of Standards and Technology.
Used for: Foot and inch definitions.