CSLB C-27 Landscaping ContractorSite Preparation and DrainageHard
A C-27 contractor is preparing a site for a new synthetic turf installation. The subgrade must be precisely graded to ensure proper drainage and a consistent playing surface. What is the typical maximum allowable deviation in elevation (tolerance) for the finished subgrade of a synthetic turf field over a 10-foot straightedge?
- A± 1/4 inch
- B± 1 inch
- C± 1/2 inch
- D± 1/8 inch
Show answer & explanationAnswer & explanation
Correct answer: A. ± 1/4 inch
Synthetic turf installations require a very precise subgrade to ensure proper drainage and a smooth, consistent playing surface. The typical maximum allowable deviation in elevation for the finished subgrade is ± 1/4 inch over a 10-foot straightedge.
Why the other options are wrong
- B. ± 1 inch is far too large a deviation for a synthetic turf subgrade, which would lead to undulations and drainage issues.
- C. ± 1/2 inch is still considered too loose a tolerance for the critical subgrade of a synthetic turf field.
- D. ± 1/8 inch is an extremely tight tolerance that is often difficult and costly to achieve consistently over large areas, typically reserved for the final setting bed layer rather than the subgrade itself.
Synthetic Turf Subgrade Tolerance
The maximum permissible variation in elevation for the finished subgrade beneath a synthetic turf installation, crucial for drainage and playability.
- Very tight tolerances are required.
- Typically ± 1/4 inch over 10 feet.
- Ensures consistent surface and proper drainage.
Memory trick: A QUARTER inch is the perfect FLAT for turf.