A E D Contractors
A| B| C10| C36DIAMOND BAR, CA 91765
(909) 374 2597View profileLicensed under Class A (General Engineering)
Find CSLB-licensed engineering and site work contractors in Diamond Bar, CA. Every listing shows an active licence number you can check yourself.
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Get matched with a licensed proGeneral engineering work in Diamond Bar sits upstream of almost every ground-up project. Grading, drainage, utility trenches and road cuts are not cosmetic decisions — they set the finished floor elevation, where stormwater goes, and whether a foundation can be poured at all. A site that drains toward the building will fight you for decades.
Ask any Class A (General Engineering) contractor what soils report they expect before quoting earthwork. Expansive clay, fill over old creek beds and shallow bedrock all change equipment choice and compaction requirements. The quote that assumes uniform dirt is the one that grows once the first bucket hits the ground. Request a walk of the lot with someone who has graded similar parcels nearby.
Utility trenches that cross property lines may need easements recorded before backfill. Ask whether the contractor coordinates with the surveyor when stakes conflict with an existing fence or driveway.
CSLB issues Class A (General Engineering) for fixed works requiring specialized engineering knowledge — grading, paving, drainage structures and utility installation fall squarely inside that scope. It is not the same licence as general building, and earthwork on a developed lot usually needs this classification.
Each contractor listed holds an active Class A (General Engineering) licence at a Diamond Bar address, with the number linked to the CSLB record. Check status and any disclosed disciplinary history before mobilization, because the first day of grading is expensive to undo.
The register records classification, not whether a firm has worked on hillside lots or tight urban infill in Diamond Bar. Ask how many grading plans they have taken through Building and Safety Division in the last two years and whether any required redesign after inspection. Specific answers beat generic assurances every time.
Every licence number below links to its record at cslb.ca.gov, where you can confirm status and expiry yourself.
14 registered in Diamond Bar · 1,973 active CLEAR licences across Los Angeles County · page 1 of 83
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Get matched with a licensed proEarthwork, paving and drainage that are the principal scope of the contract are Class A (General Engineering) work. A general building contractor may subcontract them, but the entity performing the grading typically holds Class A. Match the licence on the contract to the work described.
The register lists 14 with an active Class A (General Engineering) licence at a Diamond Bar address, and 1,973 across Los Angeles County. The figure covers grading, paving and related site work broadly.
Most cut-and-fill, driveway approaches and drainage changes need plan check through Building and Safety Division before equipment arrives. Requirements depend on disturbance area, slope and whether you are in a flood or hillside zone. Confirm with the authority before signing.
Soil conditions are unknown until excavation begins. Rock, unsuitable fill or groundwater can require over-excavation and engineered backfill. A contractor who prices without a soils assumption is guessing; one who names the assumption is easier to compare.
A licensed survey stakes property lines and finished grades. Earthwork contractors rely on those stakes; guessing the boundary risks encroachment disputes that cost more than the survey fee.