FranklyVerify the C-39 licence yourself
Take the licence number from the written estimate and look it up at cslb.ca.gov. Confirm it is active, holds the C-39 roofing classification, and that the business name matches your paperwork. Salespeople sometimes represent a licence they do not hold; the board's record settles it in a minute.
Insist the scope is written, not described
A contractor who explains the job well in your driveway and writes three lines on the estimate has given you nothing enforceable. Tear-off layers, underlayment, flashing, ventilation, and decking allowance belong on paper. In LA's spread-out market, that written scope is also the only fair way to compare bids from different parts of the county.
Use the protections California already wrote
Home improvement contracts over $500 must be written, the down payment is capped at $1,000 or 10 percent of the price — whichever is less — and you have three days to cancel. Those are not negotiating chips; they are the baseline.
Ask about crews and supervision
Larger LA companies often sell centrally and dispatch subcontracted crews across the county. Ask who supervises the tear-off, who returns for warranty work, and whether the workmanship warranty is issued by the company on your contract.